The modern pharmacology of paracetamol: therapeutic actions, mechanism of action, metabolism, toxicity and recent pharmacological findings

Acetaminophen effects upon formalin-evoked flinching, postformalin, and postincisional allodynia and conditioned place preference

Introduction

We explored in mice, the analgesic, tolerance, dependency, and rewarding effects of systemic acetaminophen (APAP).

Methods

Studies employed adult mice (C57Bl6). (1) Intraplantar formalin flinching + post formalin allodynia. Mice were given intraperitoneal APAP in a DMSO (5%)/Tween 80 (5%) or a water-based formulation before formalin flinching on day 1 and tactile thresholds assessed before and after APAP at day 12. (2) Paw incision. At 24 hours and 8 days after hind paw incision in male mice, effects of intraperitoneal APAP on tactile allodynia were assessed. (3) Repeated delivery. Mice received daily (4 days) analgesic doses of APAP or vehicle and tested upon formalin flinching on day 5. (4) Conditioned place preference. For 3 consecutive days, vehicle was given in the morning in either of 2 chambers and in each afternoon, an analgesic dose of morphine or APAP in the other chamber. On days 5 and 10, animals were allowed to select a "preferred" chamber.

Results

Formalin in male mice resulted in biphasic flinching and an enduring postformalin tactile allodynia. Acetaminophen dose dependently decreased phase 2 flinching, and reversed allodynia was observed postflinching. At a comparable APAP dose, female mice showed similarly reduced phase 2 flinching. Incision allodynia was transiently reversed by APAP. Repeated APAP delivery showed no loss of effect after sequential injections or signs of withdrawal. Morphine, but not APAP or vehicle, resulted in robust place preference.

Conclusions

APAP decreased flinching and allodynia observed following formalin and paw incision and an absence of tolerance, dependence, or rewarding properties.

Tooth Loss and Systemic Diseases in the Slovenian Elderly Population: A Cross-Sectional Study of the Associaton Between Oral and Systemic Health

Introduction

This study aimed to assess the prevalence of edentulism and tooth loss in the Slovenian elderly population, along with the associated risk factors, and investigate the association between systemic and oral health.

Methods

The study included 445 individuals aged 65 or older (average age: 79.7±8.9 years). Data on preserved teeth, dental history, chronic diseases, and medications were collected through clinical examinations. Height and weight were recorded in order to calculate body mass index (BMI), and the education level was also collected. Chronic systemic diseases and medications were categorized. Statistical analysis was conducted using linear regression and nonparametric tests.

Results

Participants had an average of 4.7±7.7 teeth, with no significant gender differences. Higher age (β=-0.185, p<0.001) and lower education level (p<0.001) were associated with fewer teeth, while higher BMI showed no correlation (β=-0.085, p=0.325). Diabetes mellitus (p=0.031), cardiovascular diseases (p=0.025), and thyroid diseases (p=0.043) were inversely related to retained teeth. This inverse relationship also applied to individuals who recovered from malignancies, not including head and neck malignancies (p=0.019). No significant relationship was found between osteoporosis and the number of teeth (p=0.573). Notably, antidiabetic drug use was inversely related to the number of teeth (p=0.004), while analgesics showed a positive relationship (p=0.022).

Conclusions

This study highlights the association between specific sociodemographic factors, chronic diseases, and retained teeth among elderly individuals in Slovenia. High edentulism rates among the elderly emphasize the need for enhanced preventive measures and risk factor management, particularly for high-risk groups like the elderly.

Crossover effect of knee and ankle joint training on knee mechanics after ACL reconstruction: A randomized controlled trial

BACKGROUND

Anterior cruciate ligament (ACL) rehabilitation is a common intervention after ACL reconstruction. Since different types of exercise can influence muscle and kinematic parameters in diverse ways, the training order between the knee and ankle joints may also change gait parameters.

PURPOSE

This study aimed to investigate whether the training sequence of the knee and ankle joints (knee followed by ankle training or vice-versa) in an ACL reconstruction (ACLR) rehabilitation program has any effects on knee extension and flexion torques.

METHODS

Forty-two men (aged 20-30 years) with ACLR participated in this study. They were randomly allocated to receive one of two interventions: (A) knee joint training followed by ankle training or (B) ankle joint training followed by knee training. After five weeks (four weeks of intervention and one-week washout), participants crossed from one group to another for an additional four weeks. Knee extension and flexion torques were assessed during the stance phase of the gait cycle before and after the intervention program.

RESULTS

Two-way Mixed-design MANOVA showed that knee extension torque improved significantly in both groups after training (p = 0.001, Cohen's D = 0.65), while the knee flexion torque increased significantly only in group B (p= 0.001, Cohen's D = 0.97). When comparing both groups, patients of group B presented significant improvements in the post-training mean values of all tested variables compared with group A.

CONCLUSION

Starting a post-ACLR rehabilitation program with ankle training followed by knee training is better to improve knee flexion and extension torques during the stance phase of the gait cycle than starting the program by training the knee first, followed by the ankle. Future studies using a mixed-gender sample and different types of ACLR operations are necessary to examine whether similar improvements will happen as well as to test their effects on many sports activities.

Association between acetaminophen administration and outcomes in critically ill patients with gout and hypertension

Background

Acetaminophen is a commonly used medication, yet its recommendation for patients with comorbid conditions of gout and hypertension is contradictory, and the impact of its usage on clinical outcomes in real-world practical settings remains uncertain. The aim of this study was to investigate the association between acetaminophen administration and clinical outcomes in critically ill patients with gout and hypertension, utilizing real-world data.

Methods

A retrospective cohort study was conducted based on the MIMIC-IV (Medical Information Mart in Intensive Care-IV) database. Adult critically ill patients with gout and hypertension were included in the analysis. The exposure was acetaminophen use during ICU stay. The primary outcome was in-hospital mortality. The secondary endpoints were frequent hospitalization, 30-day, and 60-day all-cause mortality, and incidence of hypertensive emergencies. Propensity score matching (PSM) was conducted at a 1:1 ratio. Multivariable analyses were used to adjust for confounders.

Results

The pre-matched and propensity score-matched cohorts included 2448 and 1012 patients, respectively. In the PSM analysis, in-hospital mortality was 9.7% (49/506) in the acetaminophen use group and 12.1% (61/506) in the no use group. Acetaminophen use was associated with a decrease in-hospital mortality (hazard ratio [HR], 0.62; 95% CI, 0.41-0.92; P = 0.018). In terms of secondary endpoints, after PSM, there was no statistically significant difference for both 30-day and 60-day all-cause mortality reductions in the acetaminophen use group, and HRs were 0.78 (95% CI 0.55-1.11; P = 0.175), and 0.75 (95% CI 0.55-1.02; P = 0.069), respectively. According to the analysis of dosage and treatment group, the use of APAP within the dosage range of 2-4 g and within 3-5 days of treatment significantly reduced the mortality rate of the entire cohort and PSM cohort, with statistical differences. Subgroup analysis demonstrated that lower in-hospital mortality was consistent across different baselines (age, gender, BMI, liver disease, and renal disease), with no interactions in all subgroups (interaction p-values >0.05), thereby affirming the robustness and reliability of the findings.

Conclusion

Acetaminophen use was associated with lower in-hospital mortality in critically ill patients with gout and hypertension. Prospective studies are needed to verify this finding.

Methotrexate-Loaded Surface-Modified Solid Lipid Nanoparticles Targeting Cancer Expressing COX-2 Enzyme

Cancer is a major public health problem worldwide, and it is the second leading cause of death of humans in the world. The present study has been directed toward the preparation of methotrexate-loaded surface-modified solid lipid nanoparticles (SLNs) for potential use as a chemotherapeutic formulation for cancer therapy. A lipid (C14-AAP) derived from myristic acid (C14H30O2) and acetaminophen (AAP) was employed as a targeting ligand for human breast and lung cancer cells that overexpress the cyclooxygenases-2 (COX-2) enzyme. The SLNs consisting of stearic acid and C14-AAP were characterized by several methods, including dynamic light scattering (DLS), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), ultraviolet-visible (UV-vis) spectroscopy, high-resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM) techniques. An in vitro cell cytotoxicity study was done by carrying out an MTT assay and flow cytometry study in the human breast cancer (MCF7) and human lung cancer cell line (A549). The expression level of COX-2 enzyme in MCF7 and A549 cell lines was examined by reverse transcription polymerase chain reaction (RT-PCR). A high level of COX-2 expression was observed in both cell lines. In vitro cell cytotoxicity study in MC7 and A549 cell lines showed the surface-modified, methotrexate-loaded SLN is more effective in cell killing and induction of apoptotic death in both the cell lines than free methotrexate in MTT, flow cytometry, clonogenic assay, and Western blot studies. The surface-modified SLN was radiolabeled with 99mTc with %RCP greater than 95%. In vivo biodistribution study of the 99mTc-labeled SLN in melanoma tumor-bearing C57BL6 mice showed moderate tumor uptake of the radiotracer at 3 h post injection. The SPECT/CT image aligns with the biodistribution results. This study shows that AAP-modified SLNs could be a potential chemotherapeutic formulation for cancer therapy.

Maternal administration of APAP induces angiogenesis disorders in mouse placenta via SOCS3/JAK1/STAT3 pathway

Acetaminophen (APAP, also known as paracetamol) is a commonly used antipyretic and analgesic that is considered safe to use during pregnancy. However, a growing body of research indicates that gestational administration of APAP increased the risk of neurodevelopmental, reproductive and genitourinary disorders in offspring, alongside impairments in placental development. Notably, over-dosed APAP exhibits direct toxicity to endothelial cells, but there is very limited research investigating the impact of APAP on placental angiogenesis, a gap we aim to address in this study. Pregnant mice were gavaged with APAP (15, 50 and 150 mg/kg/d) from embryonic day 11.5 (E11.5) to E13.5. Administration of 150 mg/kg/d APAP leads to low birth weight (LBW) of the offspring and disordered vascular structures within the labyrinthine (Lab) layer of the placenta. This disruption is accompanied by a significant increase in Suppressor of Cytokine Signaling 3 (SOCS3) level, a negative regulator of the Janus kinase signal transducer 1 and activator of the transcription 3 (JAK1/STAT3) signaling. Meanwhile, Human umbilical vein endothelial Cells (HUVECs) with the treatment of 3 mM APAP exhibited reduced cell viability, whereas 1 mM APAP significantly affected the proliferation, migration, invasion and angiogenic capacities of HUVECs. Further, SOCS3 was up-regulated in HUVECs, accompanied by inhibition of JAK1/STAT3 pathways. Knocking-down SOCS3 in HUVECs restored the nuclear translocation of STAT3 and efficiently promoted cellular capacity of tube formation. Overall, short-term maternal administration of overdosed APAP impairs angiogenic capacities of fetal endothelial cells via SOCS3/JAK1/STAT3 pathway in the mouse placenta. This study reveals that overdose of APAP during pregnancy may adversely affect placental angiogenesis, emphasizing the importance of adhering to the safe principles of smallest effective dose for the shortest required durations.

Evaluation of the mechanism of action of paracetamol, drotaverine, and peppermint oil and their effects in combination with hyoscine butylbromide on colonic motility: human ex-vivo study

Introduction

Drotaverine, paracetamol, and peppermint oil are often prescribed for the treatment of gastrointestinal spasm and pain. This study aimed to evaluate the effect of these drugs alone and combined with the well-known antispasmodic hyoscine butylbromide on the human colon.

Methods

Colon samples were obtained from macroscopically normal regions of 68 patients undergoing surgery and studied in muscle bath. Drotaverine, paracetamol, and peppermint oil were tested alone and in combination with hyoscine butylbromide on (1) spontaneous contractility induced by isometric stretch (in the presence of 1 µM tetrodotoxin) and (2) contractility induced by 10-5 M carbachol and after (3) electrical field stimulation-induced selective stimulation of excitatory (in the presence of 1 mM Nω-nitro-L-arginine and 10 µM MRS2179) and (4) inhibitory (under non-adrenergic, non-cholinergic conditions) pathways. (5) Drotaverine alone was also tested on cAMP-dependent pathway activated by forskolin.

Results

Compared with the vehicle, drotaverine and paracetamol (10-9-10-5 M) did not modify spontaneous contractions, carbachol-induced contractions, and responses attributed to selective activation of excitatory pathways. The addition of hyoscine butylbromide (10-7-10-5 M), concentration-dependently reduced myogenic contractions and carbachol- and electrical field stimulation-induced contractile responses. The association of paracetamol (10-4 M) and hyoscine butylbromide (10-7-10-5 M) was not different from hyoscine butylbromide alone (10-7-10-5 M). At higher concentrations (10-3M-3*10-3 M), paracetamol decreased myogenic and carbachol-induced contractions. The adenylate cyclase activator, forskolin, concentration-dependently reduced contractility, leading to smooth muscle relaxation. The effect of forskolin 10-7 M was concentration-dependently enhanced by drotaverine (10-6M-10-5M).

Discussion

Peppermint oil reduced myogenic activity and carbachol- and electrical field stimulation-induced contractions. The association of hyoscine butylbromide and peppermint oil was synergistic since the interaction index measured with the isobologram was lower than 1. No effect was seen on the neural-mediated inhibitory responses with any of the drugs studied although peppermint oil reduced the subsequent off-contraction. Drotaverine and hyoscine butylbromide have a complementary effect on human colon motility as one stimulates the cAMP inhibitory pathway and the other inhibits the excitatory pathway. Peppermint oil is synergic with hyoscine butylbromide suggesting that a combination therapy may be more effective in treating patients. In contrast, at therapeutic concentrations, paracetamol does not modify colonic contractility, suggesting that the association of paracetamol and hyoscine butylbromide has independent analgesic and antispasmodic properties.

Evaluation of the anti-inflammatory, antinociceptive, and antipyretic potential of ethanolic extract of Aristida depressa Retz through in vitro, in vivo, and in silico models

Uncontrolled inflammation is a crucial factor in the development of many diseases. Anti-inflammatory molecules based on natural sources are being actively studied, among which Aristida depressa Retz (Ar.dp) has been traditionally used as a paste to heal inflammation. The present study aimed to evaluate the anti-inflammatory, analgesic, and antipyretic potential of an ethanolic extract of A. depressa through a battery of in vivo and in vitro models. The ethanolic extract of A. depressa was prepared by maceration and chemically characterized using high-performance liquid chromatography, which revealed the presence of quercetin, vanillic acid, chlorogenic acid, p-coumaric acid, m-coumaric acid, ferulic acid, cinnamic acid, and sinapic acid; its antioxidant capacity was then screened with the DPPH in vitro assay, which indicated moderate scavenging capacity. A protein denaturation assay was next performed to evaluate the in vitro anti-inflammatory potential of Ar.dp, which showed significant inhibition (44.44%) compared to the standard drug (diclofenac sodium), with 89.19% inhibition at a concentration of 1 mg/mL. The in vivo safety profile of Ar.dp was evaluated in accordance with the OECD-425 acute toxicity guidelines and found to be safe up to 5 g/kg. The in vivo anti-inflammatory potentials of Ar.dp were evaluated at three different doses (125, 250, and 500 mg/kg) in acute (carrageenan-induced edema: 84.60%, histamine-induced paw edema: 84%), sub-chronic (cotton-pellet-induced granuloma: 57.54%), and chronic (complete-Freund's-adjuvant-induced arthritis: 82.2%) models. Our results showed that Ar.dp had significant (p < 0.05) anti-inflammatory effects over diclofenac sodium in the acute and chronic models. Histopathology studies indicated reduced infiltration of paw tissues with inflammatory cells in Ar.dp-treated animals. Similarly, Ar.dp showed significant (p < 0.05) analgesic (yeast-induced-pyrexia model: 23.53%) and antipyretic (acetic-acid-induced writhing model: 51%) effects in a time-dependent manner. In silico studies on the interactions of COX-1 and COX-2 with the eight ligands mentioned earlier confirmed the inhibition of enzymes responsible for inflammation and fever. Based on the findings of the present study, it is concluded that Ar.dp has anti-inflammatory, analgesic, and antipyretic properties that are likely linked to its pharmacologically active phenolic bioactive molecules.

Teratogenicity is more likely a function of primary and secondary pharmacology than caused by chemically reactive metabolites: a critical evaluation of 40 years of scientific research

The number of therapeutic drugs known to be human teratogens is actually relatively small. This may reflect the rigorous animal testing and well defined labelling. Some of these drugs were identified to have reactive metabolites and this has been postulated, historically, to be their teratogenic mechanism. These drugs include thalidomide, various anticonvulsants and retinoic acid derivatives.Many of these experiments were conducted in a period where chemically reactive metabolites were being intensely investigated and associated with all forms of toxicity. The legacy of this is that these examples are routinely cited as well established mechanisms.Examination of mechanism leads to the conclusion that the teratogenicity in humans of these compounds is likely due to the primary and secondary pharmacology of the parent drug and stable circulating metabolites and that association of reactive metabolites to this toxicity is unwarranted.

Maternal Administration of Acetaminophen Affects Meiosis Through its Metabolite NAPQI Targeting SIRT7 in Fetal Oocytes

Aim: Acetaminophen (APAP) is clinically recommended as analgesic and antipyretic among pregnant women. However, accumulating laboratory evidence shows that the use of APAP during pregnancy may alter fetal development. Since fetal stage is a susceptible window for early oogenesis, we aim to assess the potential effects of maternal administration of APAP on fetal oocytes. Results: Pregnant mice at 14.5 dpc (days post-coitus) were orally administered with APAP (50 and 150mg/kg.bw/day) for 3 days; meanwhile, 14.5 dpc ovaries were collected and cultured with APAP or its metabolite N-acetyl-p-benzoquinone imine (NAPQI; 5 and 15 μM) for 3 days. It showed that APAP caused meiotic aberrations in fetal oocytes through its metabolite NAPQI, including meiotic prophase I (MPI) progression delay and homologous recombination defects. Co-treatment with nicotinamide (NAM) or nicotinamide riboside chloride (NRC), nicotinamide adenine dinucleotide (NAD+) supplements, efficiently restored the MPI arrest, whereas the addition of the inhibitor of sirtuin 7 (SIRT7) invalidated the effect of the NAD+ supplement. In addition, RNA sequencing revealed distorted transcriptomes of fetal ovaries treated with NAPQI. Furthermore, the fecundity of female offspring was affected, exhibiting delayed primordial folliculogenesis and puberty onset, reduced levels of ovarian hormones, and impaired developmental competence of MII oocytes. Innovation: These findings provide the first known demonstration that NAPQI, converted from maternal administration of APAP, disturbs meiotic process of fetal oocytes and further impairs female fecundity in adulthood. The concomitant oral dosing with NAM further supports the benefits of NAD+ supplements on oogenesis. Conclusion: Short-term administration of APAP to pregnant mouse caused meiotic aberrations in fetal oocytes by its metabolite NAPQI, whereas co-treatment with NAD+ supplement efficiently relieves the adverse effects by interacting with SIRT7.

Acute ingestion of acetaminophen improves cognitive and repeated high intensity short-term maximal performance in well-trained female athletes: a randomized placebo-controlled trial

This study examined the effect of acute acetaminophen (ACTP) ingestion on physical performance during the 5 m shuttle run test (5mSRT), attention, mood states, and the perception of perceived exertion (RPE), pain (PP), recovery (PRS), and delayed onset of muscle soreness (DOMS) in well-trained female athletes. In a randomized, placebo-controlled, double-blind, crossover trial, fifteen well-trained female athletes (age 21 ± 2 years, height 165 ± 6 cm, body mass 62 ± 5 kg) swallowed either 1.5 g of ACTP or 1.5 g of placebo. The profile of mood states (POMS) and digit cancellation (DCT) were assessed 45 min postingestion, and 5mSRT was performed 60 min postingestion. The RPE and PP were determined immediately after each 30-s repetition of the 5mSRT, and the PRS and DOMS were recorded at 5 min and 24 h post-5mSRT. For the 5mSRT, ACTP ingestion improved the greatest distance (+ 10.88%, p < 0.001), total distance (+ 11.33%, p = 0.0007) and fatigue index (+ 21.43%, p = 0.0003) compared to PLA. Likewise, the DCT score was better on the ACTP (p = 0.0007) than on the PLA. RPE, PP, PRS, and DOMS scores were improved after ACTP ingestion (p < 0.01 for all comparisons) compared to PLA. POMS scores were enhanced with ACTP ingestion compared to PLA (p < 0.01). In conclusion, this study indicates that acute acetaminophen ingestion can improve repeated high intensity short-term maximal performance, attention, mood states, and perceptions of exertion, pain, recovery, and muscle soreness in well-trained female athletes, suggesting potential benefits for their overall athletic performance and mood state.

Beyond Traditional Pain Relief: A Review of Alternative Analgesics in Myocardial Infarction Patient Management

While morphine is the recommended first-line treatment for pain management in patients with acute coronary syndrome, recent studies have raised concerns about its association with adverse outcomes. Morphine has been found to cause delayed antiplatelet effects, decreased ticagrelor absorption, increased platelet reactivity, and compromised efficacy of dual antiplatelet therapy (DAPT). Alternative analgesics, such as lidocaine, fentanyl, and acetaminophen, have begun to emerge as viable alternatives, each with unique mechanisms and potential benefits. Lidocaine is demonstrated to have superior effects in reducing microvascular obstruction and fewer adverse events compared to fentanyl, despite being less effective in pain reduction. Fentanyl, which shows rapid onset and powerful analgesic properties, may interfere with ticagrelor absorption, potentially affecting platelet inhibition. Acetaminophen, a centrally acting analgesic, emerges as a safer alternative with comparable pain relief efficacy and minimal side effects. The results of multiple clinical trials emphasize the significance of customizing pain management approaches to match individual patient profiles and achieving the optimal balance between pain relief and potential adverse outcomes.

Silicon-Based Piezo Micropumps Enable Fully Flexible Drug Delivery Patterns

Drug release plays a crucial role in drug delivery. While current formulation approaches are capable of coarse-tuning the release profile, their precision and reproducibility are limited by the physicochemical properties of the excipients and active pharmaceutical ingredient (API). Innovative and advanced approaches are urgently needed, especially for site-specific targeting of drugs and to address their pharmacological requirements for optimal therapy. The 5 × 5 × 0.6 mm3 piezoelectric micropump developed by Fraunhofer EMFT was designed to enable precise drug delivery in a low volume format. In this study, we investigated the ability of the micropump to deliver solutions of highly soluble APIs using a wide range of customized pump profiles. Additionally, we examined the ability of the micropump to deliver suspensions containing various defined particle sizes. While results for suspensions indicate that pumping performance is highly dependent on the size and concentration of the suspended particles, results with API solutions demonstrate high precision and reproducibility of release, coupled with maximum flexibility in the release profile of the API. The piezoelectric micropump thus lays the cornerstone in the development of a wide range of innovative drug delivery profiles, enabling customized release profiles to be programmed and thus paving the way to fully personalized medicine.

Causal relationship between anti-inflammatory drugs and cancer: a pan-cancer study with Mendelian randomization

Background

Numerous epidemiological studies have elucidated the intricate connection between inflammation and cancer, highlighting how sustained inflammatory responses can fuel carcinogenesis by fostering proliferation, angiogenesis, and metastasis, while dampening immune responses and sensitivity to chemotherapy. Previous clinical investigations have underscored the potential of anti-inflammatory medications in either preventing or mitigating tumor formation. Here, the causal relationship between anti-inflammatory drugs and cancer was further explored through Mendelian randomization studies.

Methods

Employing Mendelian randomization, we scrutinized the causal links between three anti-inflammatory drugs-NSAIDs, Aspirin, and Anilide-and 37 types of cancer. We primarily utilized inverse variance weighting (IVW) as the primary analytical approach to delineate the causal association between these drugs and cancer types. Concurrently, sensitivity analyses were conducted to ascertain the absence of horizontal pleiotropy and heterogeneity.

Results

Our investigation revealed a discernible causal relationship between certain anti-inflammatory drugs and a subset of cancers, albeit without a pervasive impact across all cancer types. Specifically, NSAIDs exhibited a risk-reducing effect on non-small cell lung cancer (OR: 0.76, 95% CI: 0.59-0.97, p-value: 0.03) and gastric cancer (OR: 0.57, 95% CI: 0.34-0.98, p-value: 0.04). Conversely, aspirin was associated with an increased risk of oral malignant tumors (OR: 2.18, 95% CI: 1.13-4.21, p-value: 0.02). Notably, no statistically significant findings were observed for anilide drugs (p < 0.05).

Conclusion

We identified several cancers with potential causal links to NSAIDs, including non-small cell lung cancer and gastric cancer. Despite our extensive analysis, we did not identify a substantial causal relationship between the use of anti-inflammatory drugs and the development of various cancers.

Assessing the impact of COVID-19 era drug combinations on hepatic functionality: A thorough investigation in adult Danio rerio

Current and thorough information on the ecotoxicological consequences of pharmaceuticals is accessible globally. However, there remains a substantial gap in knowledge concerning the potentially toxic effects of COVID-19 used drugs, individually and combined, on aquatic organisms. Given the factors above, our investigation assumes pivotal importance in elucidating whether or not paracetamol, dexamethasone, metformin, and their tertiary mixtures might prompt histological impairment, oxidative stress, and apoptosis in the liver of zebrafish. The findings indicated that all treatments, except paracetamol, augmented the antioxidant activity of superoxide dismutase (SOD) and catalase (CAD), along with elevating the levels of oxidative biomarkers such as lipid peroxidation (LPX), hydroperoxides (HPC), and protein carbonyl content (PCC). Paracetamol prompted a reduction in the activities SOD and CAT and exhibited the most pronounced toxic response when compared to the other treatments. The gene expression patterns paralleled those of oxidative stress, with all treatments demonstrating overexpression of bax, bcl2, and p53. The above suggested a probable apoptotic response in the liver of the fish. Nevertheless, our histological examinations revealed that none of the treatments induced an apoptotic or inflammatory response in the hepatocytes. Instead, the observed tissue alterations encompassed leukocyte infiltration, sinusoidal dilatation, pyknosis, fatty degeneration, diffuse congestion, and vacuolization. In summary, the hepatic toxicity elicited by COVID-19 drugs in zebrafish was less pronounced than anticipated. This attenuation could be attributed to metformin's antioxidant and hormetic effects.

Acetaminophen influences musculoskeletal signaling but not adaptations to endurance exercise training

Acetaminophen (ACE) is a widely used analgesic and antipyretic drug with various applications, from pain relief to fever reduction. Recent studies have reported equivocal effects of habitual ACE intake on exercise performance, muscle growth, and risks to bone health. Thus, this study aimed to assess the impact of a 6-week, low-dose ACE regimen on muscle and bone adaptations in exercising and non-exercising rats. Nine-week-old Wistar rats (n = 40) were randomized to an exercise or control (no exercise) condition with ACE or without (placebo). For the exercise condition, rats ran 5 days per week for 6 weeks at a 5% incline for 2 min at 15 cm/s, 2 min at 20 cm/s, and 26 min at 25 cm/s. A human equivalent dose of ACE was administered (379 mg/kg body weight) in drinking water and adjusted each week based on body weight. Food, water intake, and body weight were measured daily. At the beginning of week 6, animals in the exercise group completed a maximal treadmill test. At the end of week 6, rats were euthanized, and muscle cross-sectional area (CSA), fiber type, and signaling pathways were measured. Additionally, three-point bending and microcomputer tomography were measured in the femur. Follow-up experiments in human primary muscle cells were used to explore supra-physiological effects of ACE. Data were analyzed using a two-way ANOVA for treatment (ACE or placebo) and condition (exercise or non-exercise) for all animal outcomes. Data for cell culture experiments were analyzed via ANOVA. If omnibus significance was found in either ANOVA, a post hoc analysis was completed, and a Tukey's adjustment was used. ACE did not alter body weight, water intake, food intake, or treadmill performance (p > .05). There was a treatment-by-condition effect for Young's Modulus where placebo exercise was significantly lower than placebo control (p < .05). There was no treatment by condition effects for microCT measures, muscle CSA, fiber type, or mRNA expression. Phosphorylated-AMPK was significantly increased with exercise (p < .05) and this was attenuated with ACE treatment. Furthermore, phospho-4EBP1 was depressed in the exercise group compared to the control (p < .05) and increased in the ACE control and ACE exercise group compared to placebo exercise (p < .05). A low dose of ACE did not influence chronic musculoskeletal adaptations in exercising rodents but acutely attenuated AMPK phosphorylation and 4EBP1 dephosphorylation post-exercise.

Polymorphism Dependent Cytotoxicity, Cellular Uptake, and Live Cell Imaging Studies on Napthalimide-Vinyl-Phenothiazine Conjugate

Polymorphism-dependent cytotoxicity and cellular uptake of drug molecules have been studied for the past two decades. However, the visualization of polymorph-dependent cellular uptake and cytotoxicity using microscopy imaging techniques has not yet been reported. The luminescent polymorph is an ideal candidate to validate the above hypothesis. Herein, we report the polymorph-dependent cellular uptake, cytotoxicity, and bio-imaging functions of polymorphs 1Y and 1R of a naphthalimide-phenothiazine dyad. These polymorphs show different luminescence colors in the solid state and exhibit aggregation-induced enhanced emission (AIEE) in the DMSO-Water mixture. Bioimaging, cytotoxicity assay, and fluorescence-activated cell sorting (FACS) studies revealed that these polymorphs show different levels of cytotoxicity, cellular uptake, localization, and imaging potential. Detailed photophysical, morphological, and biological studies revealed that the difference in molecular conformation in these polymorphs enables them to form aggregates of different sizes and morphology, which leads to the differential uptake of these into the cells and consequently shows different cytotoxicity and imaging potentials.

Preemptive use of ibuprofen and desensitizer decreases immediate tooth sensitivity after in-office bleaching: A triple-blind, randomized, placebo-controlled clinical trial

BACKGROUND

The authors evaluated the synergistic analgesic effect of preemptive administration of 400 mg of ibuprofen (IBU) and potassium fluoride 2% (KF2), both in isolation or combination, on the painful perception of tooth sensitivity after tooth bleaching.

METHODS

Fifteen patients participated in this triple-blind, randomized, placebo-controlled clinical trial. The study used a crossover design for drug administration and a split-mouth design for desensitizer agent. Four paired groups were formed: IBU plus KF2 (IBU + KF2); IBU (IBU + placebo KF); KF2 (placebo IBU + KF2), and placebo (placebo IBU + placebo KF). The outcome measure was the perception of tooth sensitivity, assessed using a visual analog scale. Data were collected at 4 different times: immediately after tooth bleaching (baseline) and after 6, 30, and 54 hours. Statistical analysis was performed using the Friedman test and relative risk.

RESULTS

IBU plus KF2 was found to be more effective in reducing tooth sensitivity immediately after bleaching (baseline) compared with the placebo group (P < .05). The risk of experiencing moderate or severe tooth sensitivity was approximately 4 times higher in the placebo group than in the IBU plus KF2 group (relative risk, 4.00; 95% CI, 1.01 to 15.81; P = .025).

CONCLUSIONS

The combined use of 400 mg of IBU and KF2 appears to be beneficial in managing postbleaching tooth sensitivity. It provides a superior analgesic effect compared with placebo.

PRACTICAL IMPLICATIONS

The preemptive administration of IBU plus KF2 reduces tooth sensitivity after tooth whitening when compared with placebo. This clinical trial was registered in the Brazilian Clinical Trials Registry Platform. The registration number is U1111-1249-8191.

Exploring acetaminophen prodrugs and hybrids: a review

This critical review highlights the advances in developing new molecules for treating pain syndrome, an important issue for human health. Acetaminophen (APAP, known as paracetamol) and nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in clinical practice despite their adverse effects. Research is being conducted to develop innovative drugs with improved pharmaceutical properties to mitigate these effects. A more practical way to achieve that is to study well-known and time-tested drugs in their molecular combinations. Accordingly, the present work explores APAP and their combined chemical entities, i.e., prodrugs (soft drugs), codrugs (mutual prodrugs), and hybrids. Due to their molecular structure, APAP prodrugs or codrugs could be considered merged or conjugated hybrids; all these names are very fluid terms. This article proposed a structural classification of these entities to better analyze their advances. So, the following: carrier-linked O-modified APAP, -linked N-modified APAP derivatives (prodrugs), and direct- and spacer-N,O-linked APAP hybrids (codrugs) are the central parts of this review and are examined, especially ester and amide NSAID-APAP molecules. The C-linked APAP and nitric oxide (NO)-releasing APAP hybrids were also briefly discussed. Prime examples of APAP-based drugs such as propacetamol, benorylate, acetaminosalol, nitroparacetamol, and agent JNJ-10450232 weave well into this classification. The proposed classification is the first and original, giving a better understanding of the SAR studies for new pain relievers research and the design development for the analgesic APAP-(or NSAID)-based compounds.

What a pain in the … back: a review of current treatment options with a focus on naproxen sodium

Non-specific low back pain (LBP) represents a challenging and prevalent condition that is one of the most common symptoms leading to primary care physician visits. While established guidelines recommend prioritizing non-pharmacological approaches as the primary course of action, pharmacological treatments are advised when non-pharmacological approaches are ineffective or based on patient preference. These guidelines recommend non-steroidal anti-inflammatory drugs (NSAIDs) or skeletal muscle relaxers (SMRs) as the first-line pharmacological options for acute or subacute LBP, while NSAIDs are the exclusive first-line pharmacological option for chronic LBP. Although SMRs are generally effective for acute LBP, the available evidence does not support the view that they improve functional recovery, and their comparative efficacy to NSAIDs and other analgesics remains unknown, while studies have shown them to introduce adverse events without significantly reducing LBP. Moreover, opioids continue to be widely prescribed for LBP, despite limited evidence for effectiveness and known risks of addiction and overdose. Broader use of non-opioid pharmacotherapy, including the appropriate use of OTC options, is critical to addressing the opioid crisis. The balance of evidence indicates that NSAIDs have a favorable benefit-risk profile when compared to other available pharmacological treatment options for non-specific LBP, a condition that is primarily acute in nature and well-suited for self-treatment with OTC analgesics. While clinical guidelines do not differentiate between NSAIDs, evidence indicates that OTC naproxen sodium effectively relieves pain across multiple types of pain models, and furthermore, the 14-h half-life of naproxen sodium allows sustained, all day pain relief with reduced patient pill burden as compared to shorter acting options. Choosing the most appropriate approach for managing LBP, including non-pharmacological options, should be based on the patient's condition, severity of pain, potential risks, and individual patient preference and needs.

Analgesic onset and efficacy of a fast-acting formulation of acetaminophen in a postoperative dental impaction pain model

OBJECTIVES

Speed of onset can be critical to an analgesic's efficacy treating acute pain. To enhance onset, a new oral acetaminophen formulation intended to be fast acting was developed. Two studies evaluated the analgesic onset, efficacy, and safety of this fast-acting acetaminophen (FA-acetaminophen) tablet relative to commercial acetaminophen caplets (ES-acetaminophen) and commercial ibuprofen liquid-filled gelatin capsules (LG-ibuprofen).

METHODS

Two single-center, single-dose, inpatient, randomized, double-blind, triple-dummy, placebo-controlled, parallel group design clinical trials were conducted using the postoperative dental impaction pain model. Subjects were healthy men and women aged 17-50 years experiencing moderate-to-severe pain after surgical extraction of at least three impacted third molars. In both studies, four treatment groups were evaluated: 1,000 mg acetaminophen as two 500 mg FA-acetaminophen tablets, 1,000 mg as two 500 mg ES-acetaminophen caplets, 400 mg ibuprofen as two 200 mg LG-ibuprofen capsules, and placebo. To maintain blinding, each subject received six units of study medication. Times to confirmed perceptible pain relief (TCPR) and meaningful pain relief (TMPR) were obtained using the double-stopwatch method. Pain intensity and relief were measured over 6 h following drug administration using a 0-10 numerical rating scale. Time to use of rescue medication (naproxen sodium) and subject global evaluations of study medications at 6 h were collected. Pharmacokinetic blood sampling and safety assessments were performed.

RESULTS

Studies 1 and 2 enrolled 240 and 420 subjects, respectively. No clinically important differences among treatment groups were observed for any demographic or baseline characteristics. Efficacy results showed all active treatments statistically superior to placebo. In Study 1, TCPR was statistically significantly shorter for FA-acetaminophen compared to ES-acetaminophen and LG-ibuprofen. In Study 2, no statistically significant differences in TCPR were noted across the active treatment groups. In Study 1, FA-acetaminophen 1,000 mg provided significantly shorter TMPR compared with LG-ibuprofen but not compared with ES-acetaminophen. In Study 2, no significant differences in TMPR were noted across the active treatment groups. In both Study 1 and 2 at 15 min after administration of study drug, PID and PAR scores were greater for FA-acetaminophen than LG-ibuprofen.

CONCLUSIONS

Both studies suggested FA-acetaminophen had faster onset of action compared to ES-acetaminophen and LG-Ibuprofen. In light of the difference in TCPR and TMPR results between Study 1 and 2, an additional study is needed to further investigate time to analgesic onset of FA-acetaminophen compared with ES-acetaminophen and LG-Ibuprofen.

STUDY REGISTRY NUMBERS

Study 1: NCT02735122; Study 2: NCT03224403.

An inexpensive paracetamol sensor based on an acid-activated carbon fiber microelectrode

Paracetamol, a contaminant of emerging concern, has been detected in different bodies of water, where it can impact ecological and human health. To quantify this paracetamol, electroanalytical methods have gained support. Thus, the present study developed a simple, inexpensive, and environmentally friendly method for paracetamol quantification using a carbon fiber microelectrode based on commercial carbon fiber. To improve the carbon fiber microelectrode's paracetamol sensitivity and selectivity, it was subjected to an activation process via electrochemical oxidation in an acid medium (H2SO4 or HNO3), using 20 consecutive cycles of cyclic voltammetry. The treated (activated) carbon fiber microelectrode was characterized using scanning electron microscopy and electrochemical techniques, including chronoamperometry and electrochemical impedance spectroscopy. The H2SO4-activated carbon fiber microelectrode exhibited enhanced figures of merit, with a linear dynamic range of paracetamol detection from 0.5 to 11 μmol L-1 and a limit of detection of 0.21 μmol L-1 under optimized conditions. The method was optimized by quantifying paracetamol in commercial pharmaceutical tablets, spiked running tap water, and river water (Pita River, Quito, Ecuador, latitude -0.364955°, longitude -78.404538°); the respective recovery values were 102.89, 103.93, and 112.40%. The results demonstrated an acceptable level of accuracy and the promising applicability of this carbon fiber microelectrode as a sensor to detect paracetamol.

Pharmacokinetics, clinical efficacy and safety of acetaminophen (paracetamol) in adult horses with naturally occurring chronic lameness

BACKGROUND

Acetaminophen is used clinically in horses with musculoskeletal pain; however, no studies have been performed in horses with chronic lameness.

OBJECTIVES

To determine the pharmacokinetics, safety and efficacy of chronic dosing of acetaminophen in horses with naturally occurring chronic lameness.

STUDY DESIGN

Longitudinal.

METHODS

Twelve adult horses with chronic lameness were treated with acetaminophen (30 mg/kg PO) every 12 h for 21 days. Plasma concentrations of acetaminophen were analysed on days 7 and 21 via LC-MS/MS and noncompartmental pharmacokinetic analysis. Lameness was evaluated by body-mounted inertial sensor (BMIS) and 10-point subjective lameness score on day 21 and compared to untreated baseline evaluation on day 35. Clinicopathological analysis (n = 12), hepatic biopsy (n = 6) and gastroscopy (n = 6) were evaluated on days -1 and 22.

RESULTS

Maximum plasma acetaminophen concentration (Cmax ) was 20.83 ± 10.25 μg/mL at time (Tmax ) 0.40 ± 0.22 h on day 7. The Cmax on day 21 was 17.33 ± 6.91 μg/mL with a Tmax of 0.67 ± 0.26 h. Subjective lameness scores significantly improved at 2 and 4 h post-treatment; Significant percent improvement was detected in PDmax for horses with hindlimb lameness at 1, 2 and 8 h post-treatment. There were no significant differences in gastroscopy or hepatic biopsy scores between days -1 and 22.

MAIN LIMITATIONS

Small sample size, multi-limb lameness of varying severity and aetiology, lack of intermediary lameness evaluation.

CONCLUSIONS

In horses with naturally occurring chronic lameness, acetaminophen at 30 mg/kg produced a transient improvement in subjective lameness and BMIS evaluation. Acetaminophen may not be effective as a monotherapy. Acetaminophen was safe following 21 days of 30 mg/kg PO every 12 h, with no evidence of clinically significant changes in clinicopathological analysis, hepatic biopsy or gastric ulceration scores.

Chitosan Soft Matter Vesicles Loaded with Acetaminophen as Promising Systems for Modified Drug Release

Our study was designed to acquire, characterize and evaluate the biocompatibility of novel lipid vesicles loaded with acetaminophen (APAP) and coated with chitosan (CS). We investigated the in vitro and in vivo drug release kinetics from these systems, and we conducted assessments for both in vitro hemocompatibility and in vivo biocompatibility. For the in vivo biocompatibility evaluation, the mice were randomly divided into four groups of six animals and were treated orally as follows: control group: 0.1 mL/10 g body weight of double-distilled water; CS group: 0.1 mL/10 g body weight 1% CS solution; APAP group: 150 mg/kg body weight APAP; APAP-v group: 150 mg/kg body weight APAP-loaded lipid vesicles. The impact of APAP-v on various hematological, biochemical, and immune parameters in mice were assessed, and the harvested tissues were subjected to histopathological examination. The innovative formulations effectively encapsulating APAP within soft vesicles exhibited reasonable stability in solution and prolonged drug release in both in vitro and in vivo studies. The in vitro hemolysis test involving APAP-loaded vesicles revealed no signs of damage to red blood cells. The mice treated with APAP-v showed neither significant variances in hematological, biochemical, and immune parameters, nor structural changes in the examined organ samples, compared to the control group. APAP-v administration led to prolonged drug release. We can conclude that the APAP-v are innovative carrier systems for modifying drug release, making them promising candidates for biomedical applications.

Prolonged sleep deprivation induces a cytokine-storm-like syndrome in mammals

Most animals require sleep, and sleep loss induces serious pathophysiological consequences, including death. Previous experimental approaches for investigating sleep impacts in mice have been unable to persistently deprive animals of both rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS). Here, we report a "curling prevention by water" paradigm wherein mice remain awake 96% of the time. After 4 days of exposure, mice exhibit severe inflammation, and approximately 80% die. Sleep deprivation increases levels of prostaglandin D2 (PGD2) in the brain, and we found that elevated PGD2 efflux across the blood-brain-barrier-mediated by ATP-binding cassette subfamily C4 transporter-induces both accumulation of circulating neutrophils and a cytokine-storm-like syndrome. Experimental disruption of the PGD2/DP1 axis dramatically reduced sleep-deprivation-induced inflammation. Thus, our study reveals that sleep-related changes in PGD2 in the central nervous system drive profound pathological consequences in the peripheral immune system.

GPER involvement in inflammatory pain

Chronic pain is a worldwide refractory health disease that causes major financial and emotional burdens and that is devastating for individuals and society. One primary source of pain is inflammation. Current treatments for inflammatory pain are weakly effective, although they usually replace analgesics, such as opioids and non-steroidal anti-inflammatory drugs, which display serious side effects. Emerging evidence indicates that the membrane G protein-coupled estrogen receptor (GPER) may play an important role in the regulation of inflammation and pain. Herein, we focus on the consequences of pharmacological and genetic GPER modulation in different animal models of inflammatory pain. We also provide a brief overview of the putative mechanisms including the direct action of GPER on pain transmission and inflammation.

Emergency Department Pain Management in the Older Adult

Pain assessment and management in older adults is complex and requires evaluation and consideration of the type of pain, the acuity of the condition, comorbidities, and medications. Many older adults do not receive appropriate therapy for painful conditions in the emergency department (ED). This brief review article is focused on pharmacologic agents, drug-drug interactions, drug-disease interactions, and approaches in the management of painful conditions seen in older adults in the emergency department. Recommendations for specific painful conditions such as fragility fractures are discussed.

A pill as a quick solution: association between painkiller intake, empathy, and prosocial behavior

Previous research has demonstrated a link between the administration of analgesic drugs and the reduction of empathy levels in humans. This apparent blunting effect of pain medication has been explained through shared neural mechanisms for the first-hand and the empathic experience of pain (simulation theory). Considering that analgesics are among the most consumed drugs in the world and the ability to empathize with others is fundamental to human social interactions, the aim of the present study was to investigate whether the typical day-to-day analgesic consumption rate in Austria and Germany is associated with a reduction in empathy and prosocial behavior. We therefore collected self-reports of analgesic consumption behavior as well as empathy for pain and prosocial behavior measures in an online survey (n = 940). Analyses revealed no significant association between the analgesic intake frequency and measures of empathy or prosocial behavior. However, liberal intake of analgesics (i.e. mind-set of "a pill is a quick solution") was linked to lower empathic concern and helping behavior, which may hint towards a negative effect in people who take pain medication for non-pain related issues or episodes of low pain. Nevertheless, further research is needed to investigate the effects of analgesic drugs in high frequency users.

Multi-omics approach reveals dysregulated genes during hESCs neuronal differentiation exposure to paracetamol

Prenatal paracetamol exposure has been associated with neurodevelopmental outcomes in childhood. Pharmacoepigenetic studies show differences in cord blood DNA methylation between unexposed and paracetamol-exposed neonates, however, causality and impact of long-term prenatal paracetamol exposure on brain development remain unclear. Using a multi-omics approach, we investigated the effects of paracetamol on an in vitro model of early human neurodevelopment. We exposed human embryonic stem cells undergoing neuronal differentiation with paracetamol concentrations corresponding to maternal therapeutic doses. Single-cell RNA-seq and ATAC-seq integration identified paracetamol-induced chromatin opening changes linked to gene expression. Differentially methylated and/or expressed genes were involved in neurotransmission and cell fate determination trajectories. Some genes involved in neuronal injury and development-specific pathways, such as KCNE3, overlapped with differentially methylated genes previously identified in cord blood associated with prenatal paracetamol exposure. Our data suggest that paracetamol may play a causal role in impaired neurodevelopment.

Public Knowledge, Attitudes, and Practices Regarding the Use of Over-The-Counter (OTC) Analgesics in Indonesia: A Cross-Sectional Study

Background

Over-the-counter analgesics like paracetamol and nonsteroidal antiinflammatory drugs (NSAIDs) are widely accessible to the general population. However, ensuring their safe and effective usage is crucial by considering individuals' knowledge, attitudes, and practices toward these medications.

Objective

This study aimed to assess the general population's knowledge, attitudes, and practices regarding the use of over-the-counter analgesics.

Methods

This cross-sectional study took place in Indonesia from December 2019 to June 2020. A validated questionnaire was used to survey a total of 582 respondents. A comparative analysis examined the variations in mean scores for respondents' characteristics concerning their knowledge, attitude, and practice. A regression analysis was also employed to explore the factors associated with adopting good analgesia practices.

Results

The findings of the study revealed significant differences in average knowledge scores related to gender, educational attainment, and employment status for the use of both paracetamol and NSAIDs. Regarding knowledge, the respondents demonstrated a higher average score for analgesics (4.56 ± 1.84) than NSAIDs (2.881 ± 2.40), out of a maximum score of 6 points. The results indicate that the respondents obtained a low score for attitude (6.80 ± 3.74) out of 16 points and a positive score for practice (2.71 ± 0.48) out of 3 points regarding using analgesics. Moreover, the regression analysis revealed that gender, residing near primary health care facilities, and having sound knowledge of NSAID use were significant predictors of good analgesic practice (p < 0.05).

Conclusion

The respondents demonstrated a greater understanding of analgesics compared with NSAIDs. However, despite this higher knowledge level, they had relatively low attitude scores but positive practice scores, indicating a discrepancy between attitudes and actual behavior in using analgesics.

Proteomic analysis of lysine 2-hydroxyisobutyryl in SLE reveals protein modification alteration in complement and coagulation cascades and platelet activation Pathways

BACKGROUND

Post-translational modifications (PTMs) are considered to be an important factor in the pathogenesis of Systemic lupus erythematosus (SLE). Lysine 2-hydroxyisobutyryl (Khib), as an emerging post-translational modification of proteins, is involved in some important biological metabolic activities. However, there are poor studies on its correlation with diseases, especially SLE.

OBJECTIVE

We performed quantitative, comparative, and bioinformatic analysis of Khib proteins in Peripheral blood mononuclear cells (PBMCs) of SLE patients and PBMCs of healthy controls. Searching for pathways related to SLE disease progression and exploring the role of Khib in SLE.

METHODS

Khib levels in SLE patients and healthy controls were compared based on liquid chromatography tandem mass spectrometry, then proteomic analysis was conducted.

RESULTS

Compared with healthy controls, Khib in SLE patients was up-regulated at 865 sites of 416 proteins and down-regulated at 630 sites of 349 proteins. The site abundance, distribution and function of Khib protein were investigated further. Bioinformatics analysis showed that Complement and coagulation cascades and Platelet activation in immune-related pathways were significantly enriched, suggesting that differentially modified proteins among them may affect SLE.

CONCLUSION

Khib in PBMCs of SLE patients was significantly up- or down-regulated compared with healthy controls. Khib modification of key proteins in the Complement and coagulation cascades and Platelet activation pathways affects platelet activation and aggregation, coagulation functions in SLE patients. This result provides a new direction for the possible significance of Khib in the pathogenesis of SLE patients.

Ocular penetration of oral acetaminophen in horses

BACKGROUND

Acetaminophen (paracetamol) is increasingly used to treat painful conditions in horses but its ocular penetration has not been studied.

OBJECTIVES

To determine whether orally administered acetaminophen penetrates the aqueous humour of the normal equine eye and report an aqueous humour:serum acetaminophen concentration ratio in horses.

STUDY DESIGN

In vivo experiment.

METHODS

Six privately owned horses with normal ophthalmic examinations weighing 568 ± 65 kg (mean ± standard deviation) and aged 11 ± 4 years were given 20 mg/kg acetaminophen orally every 12 h for a total of six doses. Physical exam parameters were recorded prior to, during, and after the dosing period. One hour after the final dose, horses were sedated and simultaneous aqueous humour and serum samples were collected and analysed for acetaminophen concentrations and selected eicosanoids. An aqueous humour:serum acetaminophen concentration ratio was calculated. A second aqueous humour sample was taken and analysed for eicosanoid concentrations 3 months after acetaminophen dosing. Physical exam data were compared between time points using a mixed model analysis (significance p < 0.05).

RESULTS

Acetaminophen was detected in both serum and aqueous humour of all horses and mean ± standard deviation aqueous humour:serum acetaminophen concentration ratio was 44.9 ± 15.9%. No significant changes in physical exam parameters occurred during or after dosing. Eicosanoids were not detected in aqueous humour at any sampling point.

MAIN LIMITATIONS

Presence of acetaminophen in the aqueous humour may not relate to clinical effect. A therapeutic level of acetaminophen has not been determined in horses, and the absence of ocular inflammation does not reflect conditions in which acetaminophen may be used.

CONCLUSIONS

Acetaminophen readily penetrates the aqueous humour of the normal equine eye after consecutive oral dosing. Further study is required to determine whether acetaminophen is useful in the treatment of ocular pain and inflammation.

Pharmacokinetics of single dose administration of three increasing doses of acetaminophen per os in 1-3-month-old foals

BACKGROUND

Acetaminophen is a common analgesic and antipyretic drug used in human medicine and might be an alternative to nonsteroidal anti-inflammatory drugs for treating pain and pyrexia in foals. The pharmacokinetics and safety of differing doses of acetaminophen have not been investigated in foals.

OBJECTIVES

To determine the plasma pharmacokinetics and any changes in haematology and biochemistry profiles following oral administration of single doses of acetaminophen at 10, 20, and 40 mg/kg to foals.

STUDY DESIGN

Randomised cross-over pharmacokinetic study.

METHODS

Six Quarter Horse (two colts and four fillies) foals received 10, 20, and 40 mg/kg acetaminophen orally once. Haematology and biochemistry profiles were performed before and 7 days after each drug administration. Blood samples were collected over 64 h after drug administration and were used to quantify plasma acetaminophen concentrations by liquid chromatography. Pharmacokinetic parameters were determined using compartmental analysis.

RESULTS

Median (range) acetaminophen plasma concentrations were 4.4 (1.8-5.1), 6.3 (2.6-12.6), and 14 (7.3-18) μg/ml for the 10, 20, and 40 mg/kg doses, respectively. Median acetaminophen area under the concentration versus time curve (AUC)0-∞ ranged from 25 (11-32), 41 (22-74), and 105 (82-142) h × μg/ml for the 10, 20, and 40 mg/kg doses, respectively. Dose-normalised maximal concentrations and AUC0-∞ values were similar across dose concentrations (p > 0.05). Median terminal half-life for all doses was 2.7-2.8 h. Haematology and biochemistry profiles were normal except for blood urea nitrogen and alkaline phosphatase concentrations.

MAIN LIMITATIONS

Foals were growing throughout the study, starting at 1 month and ending at 3 months. Deposition of drugs changes with age. The sample size was small and only single doses were evaluated. No liver biopsies were performed.

CONCLUSION

Plasma disposition of acetaminophen after a single oral dose of 10, 20, and 40 mg/kg to 1-3-month-old foals varies greatly with the dose. The analgesic and antipyretic effect in foals is unknown.

Effects of coenzyme Q10 and N-acetylcysteine on experimental poisoning by paracetamol in Wistar rats

Paracetamol (PAR) is a drug widely used in human and veterinary medicine as an analgesic and antipyretic, often involved in cases of intoxication. The most common clinical signs result from damage to red blood cells and hepatocytes, and this intoxication is considered a model for the induction of acute liver failure. In the present study, the hepatoprotective effects of coenzyme Q10 (CoQ10) and N-acetylcysteine (NAC) against experimental paracetamol (PAR) poisoning were analysed. Thirty-five adult Wistar rats (Rattus novergicus albinus) were randomly assigned to five groups, and thirty-one of these survived the treatments. Negative control group (CON-) received 1mL of 0.9% NaCl orally (PO). Other groups received 1.2g/kg of PAR (PO). Positive control group (CON+) received only PAR. NAC group received 800 mg/kg intraperitoneally (IP) of NAC 1h after the administration of PAR and at 12 h received 1mL of 0.9% NaCl, IP. The fourth group (CoQ10) received 1h and 12 h after intoxication, CoQ10 (10mg/kg IP). And the fifth group (NAC+CoQ10) received NAC (800mg/kg, IP) and CoQ10 (10mg/kg, IP). After 12 hours, the rats were euthanized and necropsied to collect liver and kidney tissues for histopathological evaluation and electronic microscopy. A single dose of PAR caused severe acute hepatitis. NAC couldn't reverse the liver and kidney damages. The group that received CoQ10 and NAC had moderate liver damage, while the group that received only CoQ10 had lower values of liver enzymes and mild liver and kidney damage. Animals that received treatment with CoQ10 or NAC+CoQ10 presented normal hepatocyte mitochondria and nuclei. Although CoQ10 couldn't reverse PAR organ damage, results indicate promising hepatoprotection in Wistar rats.

Boronate-Based Oxidant-Responsive Derivatives of Acetaminophen as Proinhibitors of Myeloperoxidase

Myeloperoxidase (MPO) is an important component of the human innate immune system and the main source of a strong oxidizing and chlorinating species, hypochlorous acid (HOCl). Inadvertent, misplaced, or excessive generation of HOCl by MPO is associated with multiple human inflammatory diseases. Therefore, there is a considerable interest in the development of MPO inhibitors. Here, we report the synthesis and characterization of a boronobenzyl derivative of acetaminophen (AMBB), which can function as a proinhibitor of MPO and release acetaminophen, the inhibitor of chlorination cycle of MPO, in the presence of inflammatory oxidants, i.e., hydrogen peroxide, hypochlorous acid, or peroxynitrite. We demonstrate that the AMBB proinhibitor undergoes conversion to acetaminophen by all three oxidants, with the involvement of the primary phenolic product intermediate, with relatively long half-life at pH 7.4. The determined rate constants of the reaction of the AMBB proinhibitor with hydrogen peroxide, hypochlorous acid, or peroxynitrite are equal to 1.67, 1.6 × 104, and 1.0 × 106 M-1 s-1, respectively. AMBB showed lower MPO inhibitory activity (IC50 > 0.3 mM) than acetaminophen (IC50 = 0.14 mM) toward MPO-dependent HOCl generation. Finally, based on the determined reaction kinetics and the observed inhibitory effects of two plasma components, uric acid and albumin, on the extent of AMBB oxidation by ONOO- and HOCl, we conclude that ONOO- is the most likely potential activator of AMBB in human plasma.

Nutrition of the preterm infant with persistent ductus arteriosus: existing evidence and practical implications

The persistence of a patent ductus arteriosus (PDA) is a common condition in preterm infants with a prevalence inversely proportional to gestational age. PDA is associated with mild-to-severe gastrointestinal complications such as feeding intolerance, gastrointestinal perforation, and necrotizing enterocolitis, which represent a major challenge for the nutritional management in preterm infants. In this context, the Section on Nutrition, Gastroenterology and Metabolism and the Circulation Section of the European Society for Pediatric Research have joined forces to review the current knowledge on nutritional issues related to PDA in preterm infants. The aim of the narrative review is to discuss the clinical implications for nutritional practice. Because there is little literature on postnatal nutrition and PDA in preterm infants, further research with well-designed studies on this topic is urgently needed. Guidelines should also be developed to clearly define the implementation and course of enteral nutrition and the target nutritional intake before, during, and after pharmacologic or surgical treatment of PDA, when indicated. IMPACT: Persistent ductus arteriosus (PDA) is associated with gastrointestinal complications such as feeding intolerance, gastrointestinal perforation, and necrotizing enterocolitis, which pose a major challenge to the nutritional management of preterm infants. In PDA infants, fluid restriction may lead to inadequate nutrient intake, which may negatively affect postnatal growth and long-term health. The presence of PDA does not appear to significantly affect mesenteric blood flow and splanchnic oxygenation after enteral feedings. Initiation or maintenance of enteral nutrition can be recommended in infants with PDA.

Pharmacological Treatments and Therapeutic Drug Monitoring in Patients with Chronic Pain

Pain is an unpleasant sensory and emotional experience that affects every aspect of a patient's life and which may be treated through different pharmacological and non-pharmacological approaches. Analgesics are the drugs most commonly used to treat pain, and in specific situations, the use of opioids may be considered with caution. These drugs, in fact, do not always induce optimal analgesia in patients, and several problems are associated with their use. The purpose of this narrative review is to describe the pharmacological approaches currently used for the management of chronic pain. We review several aspects, from the pain-scale-based methods currently available to assess the type and intensity of pain, to the most frequently administered drugs (non-narcotic analgesics and narcotic analgesics), whose pharmacological characteristics are briefly reported. Overall, we attempt to provide an overview of different pharmacological treatments while also illustrating the relevant guidelines and indications. We then report the strategies that may be used to reduce problems related to opioid use. Specifically, we focus our attention on therapeutic drug monitoring (TDM), a tool that could help clinicians select the most suitable drug and dose to be used for each patient. The actual potential of using TDM to optimize and personalize opioid-based pain treatments is finally discussed based on recent scientific reports.

Rectal Acetaminophen Improves Shunt Volume and Reduces Patent Ductus Arteriosus Ligation in Extremely Preterm Infants

OBJECTIVE

An alternative therapy for preterm infants with a hemodynamically significant patent ductus arteriosus (hsPDA) is needed when cyclooxygenase inhibitors fail or where treatment is contraindicated due to coexisting renal failure, necrotizing enterocolitis, and/or intestinal perforation. No studies have evaluated the efficacy of per rectum (PR) acetaminophen. The study aimed to evaluate the efficacy of PR acetaminophen in modulating the risk of PDA ligation.

STUDY DESIGN

A retrospective matched case-control study was conducted to compare neonates born <29 weeks' gestation with evidence of hsDA, in an era when rescue rectal acetaminophen was used (January 2014-March 2018) as a treatment strategy, versus historical controls (July 2006-August 2012). All patients underwent comprehensive echocardiography assessment of ductal shunt volume according to a standardized protocol. Acetaminophen treated neonates were matched according to demographics, gestation, preintervention echocardiography features, and comorbidities. Control patients were selected when an echocardiography was performed at an equivalent postnatal age. Infants with a genetic syndrome, severe congenital malformation, or major forms of congenital heart disease excluding small atrial septal defect or ventricular septal defect, PDA, or patent formale ovale were excluded. The primary outcome was surgical ligation of the PDA. Secondary outcomes included echocardiography indices of hemodynamic significance, the composite of death, or severe BPD (defined by ventilator dependence at 36 weeks postmenstrual age). Descriptive statistics and univariate (t-tests, Fisher's exact test, and Mann-Whitney U test) analyses were used to evaluate clinical and echocardiography characteristics of the groups and compare outcomes.

RESULTS

Forty infants (20 cases and 20 controls), with similar demographic and echocardiography features, were compared. Cases received 6.8 ± 0.7 days (60 mg/kg/day) of PR acetaminophen. Responders (n = 12, 60%) had echocardiography evidence of reduced ductal diameter (2.2 mm [1.9-2.6] to 1.1 mm [0-1.7], p = 0.002), left ventricular output (363 ± 108-249 ± 61 mL/min/kg; p = 0.002) and left atrium to aortic root ratio (1.7 ± 0.3-1.3 ± 0.2; p = 0.002) following treatment. The rate of PDA ligation was 50% lower (p = 0.02) and composite outcome of death or severe bronchopulmonary dysplasia was reduced (p = 0.04) in the acetaminophen group.

CONCLUSION

Rectal acetaminophen was associated with improvement in echocardiography indices of PDA shunt volume, a 50% reduction in PDA ligation rates and a reduction in the composite outcome of death or severe BPD. Pharmacologic and further prospective clinical studies are needed.

KEY POINTS

· Many preterm infants encounter the clinical consequences of a hemodynamically significant PDA.. · The merits and optimal timing of PDA ligation remains an area of controversy amongst neonatologists.. · Cyclooxygenase inhibitors are associated with adverse events or are often contraindicated..

Pharmacokinetics of acetaminophen after a single Oral administration of 20 or 40 mg/kg to 7-9 Day-old foals

Background

Acetaminophen is utilized in human infants for pain management and fever. Neonatal foals might benefit from administration of acetaminophen but effective and safe dosage regimens for neonatal foals remains to be determined.

Objective

The objective was to determine the plasma pharmacokinetics of acetaminophen following oral administration of a single dose of 20 mg/kg or 40 mg/kg to neonatal foals. A secondary objective was to evaluate any changes in hematology and biochemistry profiles.

Study design

Randomized study.

Methods

Eight clinically healthy 7-9-day old Quarter Horse foals (3 colts and 5 fillies) received a single oral dose of acetaminophen either 20 (n = 4) or 40 (n = 4) mg/kg. Hematology and biochemistry profiles were evaluated before and 7 days after drug administration. Blood samples were collected before and 8 times after acetaminophen administration for 48 h to quantify plasma acetaminophen concentrations. Plasma pharmacokinetic parameters were estimated using non- compartmental analysis.

Results

The median peak plasma concentrations (and range) occurred at 1.5 (0.5-2) hours, and 1.0 (1-2) hours for the 20 and 40 mg/kg doses. The maximum plasma concentration (and range) was 12 (7.9-17.4) μg/mL for the 20 mg/kg dose and 14 (11-18) μg/mL for 40 mg/kg dose. The median AUC_0-∞ ranged from 46 to 100 and 79 to 160 h*-μg/mL for the 20 and 40 mg/kg dose, respectively. Hematology and biochemistry profiles remained within normal limits.

Conclusion

Plasma disposition of acetaminophen after oral administration of 20 and 40 mg/kg to neonates is comparable to adult horses. However, safety and the optimal dosage regimen of acetaminophen for treating pain and or pyrexia in neonates in this age group remains to be determined.

Evaluation of Pre-emptive Analgesia in Total Knee Arthroplasty During Early Post-operative Periods

INTRODUCTION

Pre-emptive analgesia is expected to decrease post-operative pain. The degree of soft tissue release is directly related to preoperative deformity; we presume the severity of pain has a similar correlation in patients undergoing total knee arthroplasty (TKA). The main purpose of this research was to evaluate the effects of pre-emptive analgesia of different drugs in TKA with different degrees of preoperative genu varus.

METHODS

In this prospective observational study, 67 patients were enrolled with different degrees of genu varus deformity. They were subdivided into two groups: those with ≥15° and those with <15° varus deformities of the knee. Etoricoxib 60 mg and pregabalin 75 mg were administered orally in all the patients as pre-emptive analgesia two hours before surgery. Parameters such as the amount of soft tissue release, visual analog score (VAS), knee range of motion, complications, etc. were documented from the pre-operative period to 72 hours post-TKA.

RESULTS

With pre-emptive analgesia in post-TKA patients, the VAS score demonstrated a statistically significant difference at 24, 48, and 72 hours. The comparison of intraoperative flexion between <15° and ≥15° showed a statistically significant difference with pre-emptive analgesia in post-TKA patients.

CONCLUSION

The use of etoricoxib 60 mg and pregabalin 75 mg, two hours before surgery reduced the pain scores in patients undergoing TKA with different degrees of genu varus and correlated with intraoperative parameters associated with soft medial tissue release for genu varus.

The Clinical Pharmacology and Therapeutic Evaluation of Non-Steroidal Anti-Inflammatory Drugs in Adult Horses

This review firstly examines the underlying pathophysiology of pain and inflammation associated with orthopedic disease and endotoxemia. Then, it reviews the clinical pharmacology (pharmacokinetics and pharmacodynamics) of both conventional and non-conventional NSAIDs in the adult horse, and finally provides an overview of different modalities to evaluate the therapeutic efficacy of NSAIDs in research.

Autophagy: An Emerging Target for Developing Effective Analgesics

Inadequate treatment of acute and chronic pain causes depression, anxiety, sleep disturbances, and increased mortality. Abuse and overdose of opioids and the side effects associated with chronic use of NSAID illustrate the need for development of safer and effective pain medication. Working toward this end, an in silico tool based on an emergent intelligence analytical platform that examines interactions between protein networks was used to identify molecular mechanisms involved in regulating the body's response to painful stimuli and drug treatments. Examining interactions between protein networks associated with the expression of over 20 different pain types suggests that the regulation of autophagy plays a central role in modulation of pain symptoms (see Materials and Methods). Using the topology of this regulatory scheme as an in silico screening tool, we identified that combinations of functions targeted by cannabidiol, myo-inositol, and fish oils with varying ratios of eicosapentaenoic and docosahexaenoic acids are projected to produce superior analgesia. For validating this prediction, we administered combinations of cannabidiol, myo-inositol, and fish oils to rats that received formalin injections in hind paws, prior to substance administration, and showed that analgesic effects produced by these combinations were comparable or superior to known NSAID analgesics, which suggests that these combinations have potential in treatment of pain.

Integrated Metabolomics and Network Pharmacology Investigation of Cardioprotective Effects of Myricetin after 1-Week High-Intensity Exercise

Cardiovascular adverse effects caused by high-intensity exercise (HIE) have become a public health problem of widespread concern. The therapeutic effect and metabolic regulation mechanism of myricetin, a phytochemical with potential therapeutic effects, have rarely been studied. In this study, we established mice models of different doses of myricetin intervention with 1 week of HIE after intervention. Cardiac function tests, serology, and pathological examinations were used to evaluate the protective effect of myricetin on the myocardium. The possible therapeutic targets of myricetin were obtained using an integrated analysis of metabolomics and network pharmacology and verified using molecular docking and RT-qPCR experiments. Different concentrations of myricetin improved cardiac function, significantly reduced the levels of myocardial injury markers, alleviated myocardial ultrastructural damage, reduced the area of ischemia/hypoxia, and increased the content of CX43. We obtained the potential targets and regulated metabolic network of myricetin by combined network pharmacology and metabolomics analysis and validated them by molecular docking and RT-PCR. In conclusion, our findings suggest that myricetin exerts anti-cardiac injury effects of HIE through the downregulation of PTGS2 and MAOB and the upregulation of MAP2K1 and EGFR while regulating the complicated myocardial metabolic network.

An Updated Review on the Metabolite (AM404)-Mediated Central Mechanism of Action of Paracetamol (Acetaminophen): Experimental Evidence and Potential Clinical Impact

Paracetamol remains the recommended first-line option for mild-to-moderate acute pain in general population and particularly in vulnerable populations. Despite its wide use, debate exists regarding the analgesic mechanism of action (MoA) of paracetamol. A growing body of evidence challenged the notion that paracetamol exerts its analgesic effect through cyclooxygenase (COX)-dependent inhibitory effect. It is now more evident that paracetamol analgesia has multiple pathways and is mediated by the formation of the bioactive AM404 metabolite in the central nervous system (CNS). AM404 is a potent activator of TRPV₁, a major contributor to neuronal response to pain in the brain and dorsal horn. In the periaqueductal grey, the bioactive metabolite AM404 activated the TRPV₁ channel-mGlu5 receptor-PLC-DAGL-CB1 receptor signaling cascade. The present article provides a comprehensive literature review of the centrally located, COX-independent, analgesic MoA of paracetamol and relates how the current experimental evidence can be translated into clinical practice. The evidence discussed in this review established paracetamol as a central, COX-independent, antinociceptive medication that has a distinct MoA from non-steroidal anti-inflammatory drugs (NSAIDs) and a more tolerable safety profile. With the establishment of the central MoA of paracetamol, we believe that paracetamol remains the preferred first-line option for mild-to-moderate acute pain for healthy adults, children, and patients with health concerns. However, safety concerns remain with the high dose of paracetamol due to the NAPQI-mediated liver necrosis. Centrally acting paracetamol/p-aminophenol derivatives could potentiate the analgesic effect of paracetamol without increasing the risk of hepatoxicity. Moreover, the specific central MoA of paracetamol allows its combination with other analgesics, including NSAIDs, with a different MoA. Future experiments to better explain the central actions of paracetamol could pave the way for discovering new central analgesics with a better benefit-to-risk ratio.

Attenuation of COX-2 enzyme by modulating H2O2-mediated NF-κB signaling pathway by monoamine oxidase inhibitor (MAOI): a further study on the reprofiling of MAOI in acute inflammation

OBJECTIVE

This study aims to investigate the anti-inflammatory mechanism of monoamine oxidase inhibitor (MAOI) in carrageenan (CARR) induced inflammation models to reprofile their use. We also aimed to explore the role of monoamine oxidase (MAO)-mediated H₂O₂-NF-κB-COX-2 pathway in acute inflammation.

METHODS

In vitro anti-inflammatory activity and hydrogen peroxide (H₂O₂) scavenging activity were performed according to the established procedure. Inflammation was induced using CARR in BALB/c mice at the foot paw and peritoneal cavity. Hourly measurement of paw swelling was performed. The level of nitric oxide (NO), myeloperoxidase (MPO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE₂) and nuclear factor κB (NF-κB) was determined using enzyme-linked immunosorbent assay (ELISA). Peritoneal fluid was collected to investigate total count, differential count of leukocytes, and capillary permeability.

RESULTS

In vitro anti-inflammatory evaluations revealed the potential role of MAOI to inhibit heat-induced protein denaturation and human red cell membrane destabilization. H₂O₂ inhibition activity of MAOI also proved their powerful role as an H₂O₂ scavenger. Treatment with MAOI in CARR-induced mice significantly reduced paw edema, leukocyte extravasation, and total and differential leukocyte count. The result of ELISA showed MAOI effectively reduce the level of COX-2, PGE₂ and NF-κB in inflamed tissue.

CONCLUSIONS

In short, this study demonstrates that inhibition of H₂O₂ by MAOI alleviates CARR-induced paw edema possibly by inhibiting the H₂O₂-mediated NF-κB-COX-2 pathway. The present investigation identifies MAOI might reprofile for the treatment of acute inflammation also, the MAO enzyme may use as a novel therapeutic target to design and develop new class of anti-inflammatory agents.

Role of T CD4+ cells, macrophages, C-low threshold mechanoreceptors and spinal Cav 3.2 channels in inflammation and related pain-like symptoms in murine inflammatory models

BACKGROUND AND PURPOSE

T-type calcium channels, mainly the Ca_v 3.2 subtype, are important contributors to the nociceptive signalling pathway. We investigated their involvement in inflammation and related pain-like symptoms.

EXPERIMENTAL APPROACH

The involvement of Ca_v 3.2 and T-type channels was investigated using genetic and pharmacological inhibition to assess mechanical allodynia/hyperalgesia and oedema development in two murine inflammatory pain models. The location of Ca_v 3.2 channels involved in pain-like symptoms was studied in mice with Ca_v 3.2 knocked out in C-low threshold mechanoreceptors (C-LTMR) and the use of ABT-639, a peripherally restricted T-type channel inhibitor. The anti-oedema effect of Ca_v 3.2 channel inhibition was investigated in chimeric mice with immune cells deleted for Ca_v 3.2. Lymphocytes and macrophages from either green fluorescent protein-targeted Ca_v 3.2 or KO mice were used to determine the expression of Ca_v 3.2 protein and the functional status of the cells.

KEY RESULTS

Ca_v 3.2 channels contributed to the development of pain-like symptoms and oedema in the two murine inflammatory pain models. Our results provided evidence of the involvement of Ca_v 3.2 channels located on C-LTMRs and spinal cord in inflammatory pain. Ca_v 3.2 channels located in T cells and macrophages contribute to the inflammatory process.

CONCLUSION AND IMPLICATIONS

Ca_v 3.2 channels play crucial roles in inflammation and related pain, implying that targeting of Ca_v 3.2 channels with pharmacological agents could be an attractive and readily evaluable strategy in clinical trials, to relieve chronic inflammatory pain in patients.

Predicting pain after standard pain therapy for knee osteoarthritis - the first steps towards personalized mechanistic-based pain medicine in osteoarthritis

OBJECTIVES

The prevalence of osteoarthritis (OA) is rising, and pain is the hallmark symptom of OA. Pain in OA is complicated and can be influenced by multiple joint-related factors and factors related to, e.g., physiological, epigenetic, and pain sensory profiles. Increasing evidence suggests that a subset of patients with OA are pain sensitive. This can be assessed using quantitative sensory testing (QST). Common treatments of OA are total knee arthroplasty (TKA) and administration of 3-weeks of non-steroidal anti-inflammatory drugs (NSAIDs), which provide pain relief to many patients with OA. However, approx. 20% of patients experience chronic postoperative pain after TKA, whereas NSAIDs provide an average pain relief of approx. 25%. The current topical review focuses on the emerging evidence linking pretreatment QST to the treatment response of TKA and NSAID treatments.

CONTENT

MEDLINE was systematically searched for all studies from 2000 to 2022 on pretreatment QST, TKA, and NSAIDs. Pre-clinical studies, reviews, and meta-analyses were excluded.

SUMMARY

Currently, 14 studies on TKA and four studies on NSAIDs have been published with the aim to attempt prediction of the treatment response. The QST methodologies in the studies are inconsistent, but 11/14 (79%) studies on TKA and 4/4 (100%) studies on NSAIDs report statistically significant associations between pretreatment QST and chronic postoperative pain after TKA or analgesic effect after NSAID treatment. The strength of the associations remains low-to-moderate. The most consistent pretreatment QST predictors are pressure pain thresholds, temporal summation of pain, and conditioned pain modulation.

OUTLOOK

The use of QST as predictors of standard OA treatment is interesting, but the predictive strength remains low-to-moderate. A transition of QST from a research-based setting and into the clinic is not advised until the predictive strength has been improved and the methodology has been standardized.

A Simple Stability-Indicating UPLC Method for the Concurrent Assessment of Paracetamol and Caffeine in Pharmaceutical Formulations

A fixed-dose combination of paracetamol (PCM) and caffeine (CAF) tablets/capsules is the most frequently used over-the-counter medicine for fever and headache. In this paper, a simple, reliable, sensitive, rapid, and stability-indicating ultra-performance liquid chromatography (UPLC) analytical method was proposed for simultaneously assessing PCM and CAF in pharmaceutical formulations. The UPLC method was developed on an Acquity UPLC® CSHTM C18 column, and the column oven temperature was maintained at 35 ± 5 °C with isocratic elution by using a solution of methanol and water (30:70, v/v). The maximum absorbance of PCM and CAF was observed at 272.5 nm. The flow rate was 0.2 mL/min, and the injection volume was 1 µL, with the total run time of 2 min for the separation of PCM and CAF. The proposed UPLC method was validated according to the ICH guidelines, and it demonstrated excellent linearity, with correlation coefficients of 0.9995 and 0.9999 over the concentration ranges of 40–400 and 7–70 ng/mL for PCM and CAF, respectively. The mean retention times of 0.82 ± 0.0 and 1.16 ± 0.02 were observed for PCM and CAF, respectively. The limits of detection and quantification were 16.62 and 3.86 for PCM, respectively, and 50.37 and 11.70 for CAF, respectively. PCM and CAF were subjected to acidic, alkali, oxidative, phytochemical, dry-heat, and wet-heat degradation. The method was found to well separate the analytes’ peaks from degradation peaks, with no alterations in retention times. The proposed method is linear, precise, accurate, specific, and robust, and it can indicate stability and be used for the quantitative assessment of pharmaceutical formulations comprising PCM and CAF within a short period of time.