Synergism between paracetamol and nonsteroidal anti-inflammatory drugs in experimental acute pain

The inhibitory activity of Flos Sophorae Immaturus extract and its major flavonoid components on pancreatic lipase

Inhibition of pancreatic lipase (PL) is a strategy to prevent obesity. The inhibitory effects of Flos Sophorae Immaturus (FSI) extract and its main flavonoid components, rutin and quercetin, on PL were investigated. The contents of rutin and quercetin in FSI extract were 44.10 ± 1.33 % and 6.07 ± 1.62 %, respectively. The IC50 values of FSI extract, rutin and quercetin on PL were 322, 258 and 71 μg/mL, respectively. Rutin and quercetin inhibited PL in a reversible and noncompetitive manner. The combination of rutin and quercetin exhibited synergistic inhibitory effects at low concentration. The binding of rutin/quercetin with PL caused the fluorescence quenching of protein. Fluorescence titration showed the binding affinity of quercetin with PL protein was stronger than that of rutin. Circular dichroism analysis showed the binding changed the secondary structure of PL with an increase in random coil and a decrease in α-Helix and β-Sheet. Molecular docking revealed that rutin and quercetin could interact with the amino acid residues around the catalytic site through multiple secondary interactions. In vivo studies showed that FSI extract can reduce fat absorption and promote fecal fat excretion through inhibition of PL activity, and the effects were mainly due to rutin and quercetin.

Cannabinoid Analgesia in Postoperative Pain Management: From Molecular Mechanisms to Clinical Reality

Postoperative pain (POP) is a challenging clinical phenomenon that affects the majority of surgical patients and demands effective management to mitigate adverse outcomes such as persistent pain. The primary goal of POP management is to alleviate suffering and facilitate a seamless return to normal function for the patient. Despite compelling evidence of its drawbacks, opioid analgesia remains the basis of POP treatment. Novel therapeutic approaches rely on multimodal analgesia, integrating different pharmacological strategies to optimize efficacy while minimizing adverse effects. The recognition of the imperative role of the endocannabinoid system in pain regulation has prompted the investigation of cannabinoid compounds as a new therapeutic avenue. Cannabinoids may serve as adjuvants, enhancing the analgesic effects of other drugs and potentially replacing or at least reducing the dependence on other long-term analgesics in pain management. This narrative review succinctly summarizes pertinent information on the molecular mechanisms, clinical therapeutic benefits, and considerations associated with the plausible use of various cannabinoid compounds in treating POP. According to the available evidence, cannabinoid compounds modulate specific molecular mechanisms intimately involved in POP. However, only two of the eleven clinical trials that evaluated the efficacy of different cannabinoid interventions showed positive results.

Molecular Insights into the In Vivo Analgesic and Anti-Inflammatory Activity of Indomethacin Analogues

The primary objective of this research was to identify and explore the most potent and efficacious cyclooxygenase inhibitors, utilizing indole acetic acid drugs as a lead molecule. To achieve this objective, various derivatives (2a-2c and 2e-2g) of the selected lead molecule, indomethacin, were synthesized using a reflux condensation process, targeting the hydroxyl group. The synthesized analogues were subjected to different spectroscopic procedures to determine their structure and confirm their analogues. These derivatives were further screened for acute toxicity and anti-nociceptive and anti-inflammatory activity using established protocols. Docking analysis was performed to evaluate the possible protein-ligand interaction. The test compounds were found to be safe at doses of 50, 75, 100, and 200 mg/kg, i.p. The pharmacological screening revealed that test compounds 2a-2f had a superior peripheral analgesic effect at a dose of 10 mg/kg, in comparison to the parent drug indomethacin, while compound 2g exhibited slightly lower activity at the same dose. The hot plate results showed lower central analgesic activity of the test compounds compared to the standard Tramal, but it was still significant. Anti-inflammatory results were significant, comparable to Diclofenac sodium and indomethacin, except for compounds 2b, 2c, and 2e at a dose of 10 mg/kg body weight. Molecular docking analysis demonstrated that the derived compounds had augmented negative binding energies (-149.39, -146.72, -160.85, -159.34, -140.03, and -150.91 KJ/mol) compared to the parent drugs (-141.07), which supported the research's theme of producing stronger derivatives of standard drugs with significant anti-nociceptive and anti-inflammatory potential. The derived compounds exhibited significant analgesic and anti-inflammatory activities and, therefore, have the potential to be studied further as new drug candidates for pain and inflammation.

Parenteral Ready-to-Use Fixed-Dose Combinations Including NSAIDs with Paracetamol or Metamizole for Multimodal Analgesia-Approved Products and Challenges

The combination of non-steroidal anti-inflammatory drugs (NSAIDs) with non-opioid analgesics is common in clinical practice for the treatment of acute painful conditions like post-operative and post-traumatic pain. Despite the satisfactory results achieved by oral analgesics, parenteral analgesia remains a key tool in the treatment of painful conditions when the enteral routes of administration are inconvenient. Parenteral ready-to-use fixed-dose combinations of non-opioid analgesics combinations, including NSAIDs and paracetamol or metamizole, could play a central role in the treatment of painful conditions by combining the advantages of multimodal and parenteral analgesia in a single formulation. Surprisingly, only in 2020, a parenteral ready-to-use fixed-dose combination of ibuprofen/paracetamol was launched to the market. This review aims to investigate the current availability of combinations of NSAIDs with paracetamol or metamizole in both European and American markets, and how the combination of such drugs could play a central role in a multimodal analgesia strategy. Also, we explored how the parenteral formulations of NSAIDs, paracetamol, and metamizole could serve as starting elements for the development of new parenteral ready-to-use fixed-dose combinations. We concluded that, despite the well-recognized utility of combining NSAIDs with paracetamol or metamizole, several randomized clinical trial studies demonstrate no clear advantages concerning their efficacy and safety. Future clinical trials specifically designed to assess the efficacy and safety of pre-formulated fixed-dose combinations are required to generate solid evidence about their clinical advantages.

Systemic Nonsteroidal Anti-Inflammatories for Analgesia in Postoperative Critical Care Patients: A Systematic Review and Meta-Analysis of Randomized Control Trials

While opioids are part of usual care for analgesia in the ICU, there are concerns regarding excess use. This is a systematic review of nonsteroidal anti-inflammatory drugs (NSAIDs) use in postoperative critical care adult patients.

DATA SOURCES

We searched Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, trial registries, Google Scholar, and relevant systematic reviews through March 2023.

STUDY SELECTION

Titles, abstracts, and full texts were reviewed independently and induplicate by two investigators to identify eligible studies. We included randomized control trials (RCTs) that compared NSAIDs alone or as an adjunct to opioids for systemic analgesia. The primary outcome was opioid utilization.

DATA EXTRACTION

In duplicate, investigators independently extracted study characteristics, patient demographics, intervention details, and outcomes of interest using predefined abstraction forms. Statistical analyses were conducted using Review Manager software Version 5.4. (The Cochrane Collaboration, Copenhagen, Denmark).

DATA SYNTHESIS

We included 15 RCTs (n = 1,621 patients) for admission to the ICU for postoperative management after elective procedures. Adjunctive NSAID therapy to opioids reduced 24-hour oral morphine equivalent consumption by 21.4 mg (95% CI, 11.8-31.0 mg reduction; high certainty) and probably reduced pain scores (measured by Visual Analog Scale) by 6.1 mm (95% CI, 12.2 decrease to 0.1 increase; moderate certainty). Adjunctive NSAID therapy probably had no impact on the duration of mechanical ventilation (1.6 hr reduction; 95% CI, 0.4 hr to 2.7 reduction; moderate certainty) and may have no impact on ICU length of stay (2.1 hr reduction; 95% CI, 6.1 hr reduction to 2.0 hr increase; low certainty). Variability in reporting adverse outcomes (e.g., gastrointestinal bleeding, acute kidney injury) precluded their meta-analysis.

CONCLUSIONS

In postoperative critical care adult patients, systemic NSAIDs reduced opioid use and probably reduced pain scores. However, the evidence is uncertain for the duration of mechanical ventilation or ICU length of stay. Further research is required to characterize the prevalence of NSAID-related adverse outcomes.

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.

Combination pharmacotherapy for patent ductus arteriosus: Rationale and evidence

While cyclooxygenase inhibitors have been the most common medications used to facilitate earlier closure of patent ductus arteriosus in preterm infants, adverse effects and low efficacy in extremely low gestational age neonates (ELGANs) have highlighted a need for alternative options. Combination therapy with acetaminophen and ibuprofen is a novel strategy for PDA treatment in ELGANs, as it may facilitate higher ductal closure rates via additive action on two separate pathways inhibiting prostaglandin production. Initial small observational studies and pilot randomized clinical trials indicate potentially higher efficacy of the combination regime to induce ductal closure in comparison to treatment with ibuprofen alone. In this review, we examine the potential clinical impact of treatment failure in ELGANs with significant PDA, highlight the biological rationale in support of studying combination therapy, and review the randomized and non-randomized studies to date. With the rising number of ELGANs receiving neonatal intensive care, who are vulnerable to PDA-related morbidities, there is an urgent need for adequately powered clinical trials to systematically investigate the efficacy and safety of combination therapy for PDA treatment.

Paracetamol for multimodal analgesia

Pain and related disability remain a major social and therapeutic problem. Comorbidities and therapies increase drug interactions and side effects making pain management more compounded especially in the elderly who are the fastest-growing pain population. Multimodal analgesia consists of using two or more drugs and/or techniques that target different sites of pain, increasing the level of analgesia and decreasing adverse events from treatment. Paracetamol enhances multimodal analgesia in experimental and clinical pain states. Strong preclinical evidence supports that paracetamol has additive and synergistic interactions with anti-inflammatory, opioid and anti-neuropathic drugs in rodent models of nociceptive and neuropathic pain. Clinical studies in young and adult elderly patients confirm the utility of paracetamol in multimodal, non-opioid or opioid-sparing, therapies for the treatment of acute and chronic pain.

Meloxicam in Combating Clinical Mastitis: Nanotechnology-Driven Hope and Opportunities

Mastitis has well-recognized harmful effects on dairy farm profitability. Furthermore, mastitis impairs the milk component synthesizing ability of secretary tissues. Various therapies are available for the treatment of clinical mastitis. Meloxicam exhibits preferential binding to Cyclooxygenase-2 (COX-2) receptor and consequently generates fewer negative gastrointestinal side effects than nonspecific COX inhibitors such as flunixin meglumine and ketoprofen. Toward this end, research efforts directed at understanding the use of meloxicam alone and in combination with other antibiotics to improve milk quality and production. Therefore, in this review, we have highlighted the mechanism, biopharmaceutical challenges, and merits of meloxicam usage in dairy cattle mastitis. In addition, we also presented the integration of artificial neural network, in silico docking, and nanotechnology-driven topical drug delivery cargo as future opportunity for efficient delivery of meloxicam in the management of clinical mastitis.

Evaluating Pain and Analgesia Effectiveness Following Routine Castration in Rabbits Using Behavior and Facial Expressions

Prevention of pain in rabbits is a priority for both welfare and validity of scientific data. We aimed to determine if the rabbit grimace scale (RbtGS) could be used as a viable, rapid assessment tool in two breeds of rabbit, Dutch belted (DB) and New Zealand white (NZW), following orchidectomy, as an adjunct to behavioral analysis. All animals received analgesia. Rabbits were filmed and their behavior was recorded at multiple time points pre- and post-orchidectomy. Observers then scored specific pain associated behaviors for analysis. Time matched footage was also scored using the rabbit grimace scale (RbtGS). Following surgery, rabbits showed significant increases in the duration spent displaying key pain associated behaviors at 1 and 5 h post-surgery. DB rabbits that received low dose meloxicam (0.2 mg/kg) showed significantly more pain behaviors at 1 and 5 h post-surgery compared to those administered a combination of higher dose meloxicam (0.6 mg/kg) and a lidocaine/bupivacaine local infusion. DB rabbits showed an increase in RbtGS score at both 1 and 5 h post-surgery. In the NZW rabbits, an increase in RbtGS score was only observed at 1 h post-surgery. Using behavioral analysis as the gold standard for comparison, the RbtGS was an effective means of determining when rabbits are painful following orchidectomy. Higher dose meloxicam (0.6 mg/kg) combined with local anesthetic was a more effective method of reducing pain, compared to lower dose meloxicam (0.2 mg/kg) alone.

Sterculia tragacantha Lindl Leaf Extract Ameliorates STZ-Induced Diabetes, Oxidative Stress, Inflammation and Neuronal Impairment

Background

Sterculia tragacantha is a medicinal plant commonly used in the western part of Nigeria, for managing diabetes mellitus. However, there is a dearth of scientific information on the antidiabetic and neuroprotective properties of the plant.

Methods

The in silico, in vitro and in vivo models were used to evaluate the antioxidants, antidiabetic, anti-inflammatory and neuroprotective potential of aqueous extract of Sterculia tragacantha leaf (AESTL) in streptozotocin (STZ)-induced diabetic rats. Thirty (30) male albino rats (155.34±6.33 g) were intraperitoneal injected with 40 mg/kg of freshly prepared streptozotocin and were divided into 5 groups (A-E) of 6 animals each. Groups A–D were treated with 0, 150 and 300 mg/kg of AESTL, and 200 mg/kg body weight of metformin respectively, while group E serve as the normal control.

Results

The results of in vitro analysis revealed dose-dependent antioxidant activities; ABTS (IC₅₀ = 63.03±2.57 μg/mL), DPPH (117.49±2.35 μg/mL), FRAP (15.19±0.98 mmol/100g), TAC (43.38±0.96 mg/100g), hypoglycaemic effect; α-amylase (IC₅₀ = 77.21±4.35 μg/mL) and α-glucosidase (IC₅₀ = 443.25±12.35), and anti-cholinesterase; AChE (IC₅₀ = 113.07±3.42 μg/mL) and BChE (IC₅₀ = 87.50±4.32 μg/mL) activities of AESTL. In vivo study revealed dose-dependent hypoglycemic effect and body weight improvement in rats treated with the AESTL. In addition, AESTL improved the antioxidant status and attenuated STZ-induced dysregulations of Na⁺-K⁺-ATPase, cholinesterases and neurotransmitters in the brain tissue of experimental rats. The results also demonstrated that AESTL could regulate anti-inflammatory response via inhibition of COX-2/NO signaling axis in the brain of diabetic rats. Molecular docking analysis revealed that epicatechin and procyanidin B2, the bioactive compounds from AESTL, docked well to the binding cavities of acetylcholinesterase, butyrylcholinesterase, α-amylase and α-glucosidase with binding affinities ranges between –8.0 and –11.4 kcal/mol, suggesting that these compounds are the bioactive component that could be responsible for the antidiabetic and neuroprotective activities of AESTL.

Conclusion

The results of the present study strongly suggested that the AESTL extract could be very useful for halting diabetes progression and its associated neuroinflammation complications.

Analgesic Efficacy of Etoricoxib following Third Molar Surgery: A Meta-analysis

Background

The purpose of this meta-analysis was to assess the clinical efficacy of etoricoxib in comparison with traditional NSAIDs for postoperative pain after third molar surgery.

Methods

The quality of studies found in PubMed and Google Scholar was evaluated with Cochrane Collaboration's risk of bias tool. Data on total consumption of rescue analgesics, number of patients using rescue analgesics, global assessment of study treatments, and adverse effects were extracted exclusively from high-quality clinical trials. Each meta-analysis was performed with the Review Manager Software 5.3 for Windows.

Results

The qualitative analysis showed that etoricoxib has better analgesic activity when compared with ibuprofen (2 clinical trials) and diclofenac (1 clinical trial). A similar analgesic efficacy between etoricoxib and nonselective Cox-2 NSAIDs was informed in 3/8 studies (2 compared to ibuprofen and 1 to naproxen sodium). Moreover, the number of patients requiring rescue analgesics in the postoperative period showed a statistical difference in favor of etoricoxib when compared to NSAIDs.

Conclusion

Etoricoxib significantly reduces the number of patients needing rescue analgesics compared to NSAIDs after third molar surgery.

Epicatechin Gallate as Xanthine Oxidase Inhibitor: Inhibitory Kinetics, Binding Characteristics, Synergistic Inhibition, and Action Mechanism

Epicatechin gallate (ECG) is one of the main components of catechins and has multiple bioactivities. In this work, the inhibitory ability and molecular mechanism of ECG on XO were investigated systematically. ECG was determined as a mixed xanthine oxidase (XO) inhibitor with an IC50 value of 19.33 ± 0.45 μM. The promotion of reduced XO and the inhibition of the formation of uric acid by ECG led to a decrease in O2- radical. The stable ECG-XO complex was formed by hydrogen bonds and van der Waals forces, with the binding constant of the magnitude of 104 L mol-1, and ECG influenced the stability of the polypeptide skeleton and resulted in a more compact conformation of XO. Computational simulations further characterized the binding characteristics and revealed that the inhibitory mechanism of ECG on XO was likely that ECG bound to the vicinity of flavin adenine dinucleotide (FAD) and altered the conformation of XO, hindering the entry of substrate and the diffusion of catalytic products. ECG and allopurinol bound to different active sites of XO and exerted a synergistic inhibitory effect through enhancing their binding stability with XO and changing the target amino acid residues of XO. These findings may provide a theoretical basis for the further application of ECG in the fields of food nutrition and functional foods.

Paracetamol: A Review of Guideline Recommendations

Musculoskeletal pain conditions are age-related, leading contributors to chronic pain and pain-related disability, which are expected to rise with the rapid global population aging. Current medical treatments provide only partial relief. Furthermore, non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are effective in young and otherwise healthy individuals but are often contraindicated in elderly and frail patients. As a result of its favorable safety and tolerability record, paracetamol has long been the most common drug for treating pain. Strikingly, recent reports questioned its therapeutic value and safety. This review aims to present guideline recommendations. Paracetamol has been assessed in different conditions and demonstrated therapeutic efficacy on both acute and chronic pain. It is active as a single agent and is additive or synergistic with NSAIDs and opioids, improving their efficacy and safety. However, a lack of significant efficacy and hepatic toxicity have also been reported. Fast dissolving formulations of paracetamol provide superior and more extended pain relief that is similar to intravenous paracetamol. A dose reduction is recommended in patients with liver disease or malnourished. Genotyping may improve efficacy and safety. Within the current trend toward the minimization of opioid analgesia, it is consistently included in multimodal, non-opioid, or opioid-sparing therapies. Paracetamol is being recommended by guidelines as a first or second-line drug for acute pain and chronic pain, especially for patients with limited therapeutic options and for the elderly.

Comparison of Monotherapy Versus Combination of Intravenous Ibuprofen and Propacetamol (Acetaminophen) for Reduction of Postoperative Opioid Administration in Children Undergoing Laparoscopic Hernia Repair: A Double-Blind Randomized Controlled Trial

BACKGROUND

Extensive efforts have been made toward reducing postoperative opioid use in children. In this study, we assessed whether propacetamol, or a nonsteroidal anti-inflammatory drug (NSAID), or their combination could effectively reduce opioid use in children after laparoscopic inguinal hernia repair.

METHODS

This randomized, double-blind clinical trial included 159 children aged 6 months to 6 years. Children were allocated into 1 of the following 3 groups: group I was treated with 10 mg·kg-1 ibuprofen, group P was treated with 30 mg·kg-1 propacetamol, and group I + P was treated with both drugs in their respective concentrations. If the face-legs-activity-crying-consolability (FLACC) score was ≥4 during the postanesthesia care unit stay, 1.0 µg·kg-1 fentanyl was administered as a rescue analgesic. The number of patients who received rescue fentanyl in the postanesthesia care unit was defined as the primary outcome; this was analyzed using the χ2 test. The secondary outcomes included the FLACC and the parents' postoperative pain measure (PPPM) scores until the 24-hour postoperative period.

RESULTS

Among the 144 enrolled patients, 28.6% in group I, 66.7% in group P, and 12.8% in group I + P received rescue fentanyl in the postanesthesia care unit (P < .001). The highest FLACC score was lower in group I + P than in either group I or P (P = .007 and P < .001, respectively). Group I + P presented significantly lower PPPM scores than group P at 4 and 12 hours postoperative (P = .03 and .01, respectively).

CONCLUSIONS

The use of ibuprofen plus propacetamol immediately following laparoscopic hernia repair surgery in children resulted in the reduced use of an opioid drug compared with the use of propacetamol alone.

Comparative study of inhibition mechanisms of structurally different flavonoid compounds on α-glucosidase and synergistic effect with acarbose

Flavonoid compounds have anti-diabetic activity, which can control blood glucose levels by inhibiting α-glucosidase activity. In this paper, the inhibition mechanisms between four flavonoid compounds and α-glucosidase were studied by multispectroscopic methods and molecular docking. The results showed that the inhibitory activities of flavonoid compounds were higher than that of acarbose, and the sequence of inhibition effect was scutellarein > nepetin > apigenin > hispidulin > acarbose. Also, the synergistic effects of flavonoid compounds combined with acarbose on inhibiting α-glucosidase activity were observed. The fluorescence results showed that flavonoid compounds combined with α-glucosidase to form a stable complex. And the spectral analysis indicated that the microenvironmental and secondary structure of α-glucosidase were changed. The present study demonstrated that the molecular structure of flavonoid compounds played an important role in the inhibition process, namely, scutellarein with more hydroxyl groups on the A-ring might serve as the most effective α-glucosidase inhibitor.

Synergism between oral paracetamol and nefopam in a murine model of postoperative pain

BACKGROUND

The use of paracetamol or nefopam for postoperative pain control is limited by the need of high doses associated with unwanted effects. Previous works suggest positive interactions between both compounds that may be exploited to obtain potentiation of antinociception.

METHODS

Mechanical and heat antinociception induced by oral doses of paracetamol, nefopam or their combination was studied by isobolographic analysis in a murine model of postsurgical pain. The effective doses that produced 50% antinociception (ED₅₀ ) were calculated from the log dose-response curves for each compound. Subsequently, the effects of ED_8.7 s, ED_12.5 s, ED_17.5 s and ED₃₅ s of nefopam and paracetamol combined were assessed.

RESULTS

Oral paracetamol induced dose-dependent relief of postoperative sensitivity and showed higher efficacy reducing mechanical hypersensitivity (ED₅₀ 177.3 ± 15.4 mg/kg) than heat hyperalgesia (ED₅₀ 278.6 ± 43 mg/kg). Oral nefopam induced dose-dependent antinociception with similar efficacy for mechanical and heat hypersensitivity (ED₅₀ s 5.42 ± 0.81 vs. 5.83 ± 0.72). Combinations of increasing isoeffective doses revealed that combined ED_17.5 s (85.76 mg/kg paracetamol and 1.9 mg/kg nefopam) and ED₃₅ s (132.67 mg/kg and 3.73 mg/kg) showed synergistic effects leading to 75% and 90% mechanical antinociception, respectively. These mixtures were defined by interaction indexes of 0.43 and 0.41 and ratios 45:1 and 35:1 paracetamol:nefopam, respectively. The same combinations showed additive effects for the inhibition of incisional thermal hyperalgesia.

CONCLUSIONS AND LIMITATIONS

This work describes a synergistic antinociceptive interaction between low doses of nefopam and paracetamol for the treatment of postoperative hypersensitivity to peripheral stimuli. The promising results obtained on reflexive nociceptive responses of young male mice subjected to plantar surgery highlight the interest of further research evaluating the effects of this mixture on the affective-motivational component of pain and in females and additional age groups. Confirmation of pain-relieving efficacy and safety of this oral combination clinically available in European and Asian countries could provide a useful tool for postsurgical pain management.

SIGNIFICANCE

Early postoperative pain is currently undertreated and has been recognized as a relevant source of chronic postsurgical pain. Oral efficient treatments could facilitate fast-track surgeries and patient recovery at home. Here, we identify in a mouse model of postoperative pain a potent synergistic oral combination consisting of low paracetamol and nefopam doses that provides relief of postsurgical hypersensitivity to mechanical and thermal stimuli. Oral multimodal paracetamol-nefopam mixtures represent a potential clinically available pharmacological strategy for the relief of incisional sensitivity and the promotion of patient recovery.

Indomethacin co-amorphous drug-drug systems with improved solubility, supersaturation, dissolution rate and physical stability

In this study, new co-amorphous drug systems were designed using a pharmacologically relevant combination to improve the solubility and dissolution of indomethacin. Combinations of indomethacin-paracetamol (IND-PAR) as an anti-inflammatory/pain killer, and indomethacin-nicotinamide (IND-NCT) for prevention of gastric ulcers caused by IND, were developed for co-amorphization. The effect of PAR and NCT on the solubility, supersaturation, and dissolution of the poorly soluble counterpart, IND, was investigated. PAR and NCT were found to enhance the solubility and supersaturation of IND in biorelevant medium (FaSSIF) and in FaSSIF blank. Differential scanning calorimetry (DSC) showed capability of IND-PAR and IND-NCT binary mixtures to form eutectic mixture. Powder X-ray diffraction and DSC indicated the formation of a homogenous co-amorphous system with single T_g value. Hydrogen bonding between IND and each of PAR and NCT were found to stabilize the co-amorphous systems as supported by FTIR studies. The intrinsic dissolution rate under sink conditions was improved over that of plain amorphous IND both in FaSSIF and FaSSIF blank. IND-PAR 2:1 and IND-NCT 1:1 were extremely stable and remained amorphous for 7 months at 25 °C, while all co-amorphous formulations were stable at least up to one month at 40 °C under dry condition. The present work demonstrates an improved approach to combine IND-PAR and IND-NCT as promising co-amorphous systems for potential therapeutical applications.

Acetaminophen, Nonsteroidal Anti-inflammatory Drugs, or Combination of Both Analgesics in Acute Posttrauma Pain: A Randomized Controlled Trial

OBJECTIVES

Nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen (also called paracetamol) are the most frequent analgesics used to relieve posttrauma pain in the emergency department (ED). However, the utility of combining both treatments is still controversial. We sought to explore the benefits of combining an NSAID with acetaminophen compared to acetaminophen alone, or NSAID alone, in the treatment of posttraumatic pain of the extremity after discharge from the ED.

METHODS

This is a prospective, randomized controlled trial, carried out in a single ED from March 2017 to November 2018. The included patients were randomly assigned to receive paracetamol alone, high-dose NSAID (piroxicam) alone, or a combination of paracetamol and high-dose NSAID for 7 days after ED discharge. The primary outcome was need for additional oral analgesics. Secondary outcomes included the change of the visual numeric scale (VNS) between ED discharge (VNS D0) and 7 days later (VNS D7), ED revisits for residual pain, side effects, and patient satisfaction as assessed by a Likert satisfaction scale.

RESULTS

The need for additional oral analgesics was comparable between the paracetamol-NSAID combination group (9.8%) and the paracetamol group (11.4%; p = 0.43). ED readmission rate was also comparable between the two groups at 5.6 and 5.8%, respectively (p = 0.86). In contrast, need for new analgesics and ED revisit rates were both more frequent in the high-dose NSAID group. Mean VNS decreases on day 7 compared to day 0 were 66, 63, and 67%, respectively, in the paracetamol, NSAID, and paracetamol-NSAID combination groups (p = 0.32). Frequency of dissatisfaction was higher in the NSAID group. Side effects were more frequent in the NSAID and paracetamol-NSAID combination groups.

CONCLUSION

This study found that the combination of a high-dose NSAID with paracetamol does not increase the analgesic effect compared to paracetamol alone. We also found that paracetamol alone is superior to high-dose NSAID alone for posttraumatic extremity pain.

Antinociceptive Synergy Between Metamizole and Hesperidin in a Model of Visceral Pain in Mice

BACKGROUND

Metamizole is used to relieve the visceral pain but its adverse effects limit its use. An alternative to improve its efficacy with lower doses is to combine it with a natural product as hesperidin.

AIM OF THE STUDY

The aim of this study was to evaluate the antinociceptive interaction between metamizole and hesperidin in a visceral pain model using an isobolographic analysis.

METHODS

Antinociception was evaluated in the writhing model using acetic acid (1%) to induce writhes in mice. Metamizole (1-316 mg/kg), hesperidin (3-300 mg/kg), or combinations with a fixed-dose ratio of 1:1 were administered intraperitoneally 30 min before the acetic acid and the number of writhes was counted for 30 min. Isobolographic analysis was employed to define the nature of the compound interaction.

RESULTS

Metamizole and hesperidin in individual administration induced dose-dependent antinociceptive effects, reached an efficacy of 84.2 ± 5.9% and 66.3 ± 7.4%, respectively. The ED₅₀ values calculated from their dose-response curves were 84.5 ± 22.7 and 108.9 ± 17.9 mg/kg, respectively. The analysis of DRC for the metamizole + hesperidin combination, in a ratio 1:1 showed a ED_{50 COMB} value lower than the ED_{50 ADD} estimated from the additivity line from the isobologram (46.7 ± 6.3 vs. 96.7 ± 11.9 mg/kg, respectively). In addition, the pharmacological interaction calculated was of 0.48. These results suggest a synergistic interaction for the antinociceptive activity of metamizole + hesperidin combination.

CONCLUSION

These data suggest that metamizole + hesperidin combination could be useful in treating visceral pain as it can interact synergistically using low dose of both drugs with the possibility of reducing the risk of adverse effects.

Synthesis and characterization of bipyridine cobalt(ii) complex modified graphite screen printed electrode: an electrochemical sensor for simultaneous detection of acetaminophen and naproxen

The new Co(ii) compound [Co(5,5'-dmbpy)2(NCS)2] (a1) was prepared by reacting Co(NO3)2·6H2O, 5,5'-dimethyl-2,2'-bipyridine ligand, and Na(SCN). The nano-scale size of [Co(5,5'-dmbpy)2(NCS)2] (a1) was synthesized using sonochemical process. The size of the nanoparticles (a2) was ∼13 ± 2 nm. We have also provided a new platform of electrochemical sensing for simultaneous detection of acetaminophen and naproxen using (a2) surface modified graphite screen printed electrode (SPE) in 0.1 M phosphate buffer solution (PBS, pH 7.0). In contrast to bare SPE, the modified SPE could significantly improve the electrooxidation activity of acetaminophen along with the rise in the current of an anodic peak. The peak currents acquired using differential pulse voltammetry (DPV) raised linearly with the raising of acetaminophen concentration and the sensor had a detection range over the concentration range of 0.009-325.0 μM, with a detection limit of 5.0 nM (S/N = 3). In the case of naproxen peak, currents of naproxen oxidation at the modified SPE were linearly dependent on the naproxen amounts in the range of 1.0-500.0 μM. The detection limit (S/N = 3) was calculated to be 0.03 μM. The DPV responses show that the peaks of acetaminophen and naproxen oxidation were vividly separated from one other with a potential difference of 410 mV between them. The low detection limit, high sensitivity, and stability made the relevant electrode applicable for the analysis of acetaminophen and naproxen in real samples. Further, its practical applicability was reliable and desirable in the analysis of pharmaceutical compounds and biological fluids. The benefits of using this modified electrode for the determination of analytes are compared with other works in the manuscript.

Effect of Diclofenac Potassium Premedication on Postendodontic Pain in Mandibular Molars with Symptomatic Irreversible Pulpitis: A Randomized Placebo-Controlled Double-Blind Trial

INTRODUCTION

The aim of this prospective, randomized, double-blind clinical trial was to evaluate the effect of a preoperative, single, oral dose of diclofenac potassium (DFK) on postoperative pain and rescue analgesic intake in patients with symptomatic irreversible pulpitis in mandibular molars treated in 1 visit.

METHODS

Seventy emergency patients with moderate to severe preoperative pain randomly received either 50 mg DFK or placebo tablets 1 hour before starting endodontic treatment (n = 35 per group). Patients recorded their pain level 6, 12, 24, and 48 hours after treatment on a 170-mm Heft-Parker visual analog scale. The incidence of rescue analgesic intake was also recorded. Outcome data were statistically analyzed using Mann-Whitney U, Friedman, Wilcoxon signed rank, and chi-square tests. Binary logistic regression assessed the association of predisposing factors with postoperative pain. The significance level (α) was set at 0.05.

RESULTS

Of the 70 patients, 68 were analyzed (n = 34 per group). Both groups had similar baseline characteristics (P > .05). DFK showed significantly less pain incidence and intensity than the placebo at 48 hours only (P < .05). A significant decrease occurred from 24 to 48 hours with DFK (P < .05), which was not recorded with the placebo (P > .05). No difference in the incidence of rescue analgesic intake was reported between groups (P > .05). Food intake timing, sex, and rescue analgesic intake were associated with postoperative pain (P < .05).

CONCLUSIONS

Premedication by a single, oral dose of 50 mg DFK could be effective in reducing postendodontic pain at 48 hours after 1-visit endodontic treatment in mandibular molars with symptomatic irreversible pulpitis.

Consensus Statement for the Prescription of Pain Medication at Discharge after Elective Adult Surgery

This Consensus Statement provides recommendations on the prescription of pain medication at discharge from hospital for opioid-naïve adult patients who undergo elective surgery. It encourages health care providers (surgeons, anesthesiologists, nurses/nurse practitioners, pain teams, pharmacists, allied health professionals, and trainees) to (1) use nonopioid therapies and reduce the prescription of opioids so that fewer opioid pills are available for diversion and (2) educate patients and their families/caregivers about pain management options after surgery to optimize quality of care for postoperative pain. These recommendations apply to opioid-naïve adult patients who undergo elective surgery. This consensus statement is intended for use by health care providers involved in the management and care of surgical patients. A modified Delphi process was used to reach consensus on the recommendations. First, the authors conducted a scoping review of the literature to determine current best practices and existing guidelines. From the available literature and expertise of the authors, a draft list of recommendations was created. Second, the authors asked key stakeholders to review and provide feedback on several drafts of the document and attend an in-person consensus meeting. The modified Delphi stakeholder group included surgeons, anesthesiologists, residents, fellows, nurses, pharmacists, and patients. After multiple iterations, the document was deemed complete. The recommendations are not graded because they are mostly based on consensus rather than evidence.

Acetaminophen Safety: Risk of Mortality and Cardiovascular Events in Nursing Home Residents, a Prospective Study

BACKGROUND

Acetaminophen is the most widely used analgesic today. A recent systematic review found increased adverse events and mortality at therapeutic dosage. Our aim was to challenge these results in a large sample of older adults living in nursing homes (NHs).

DESIGN

Prospective study using data from the Impact of Educational and Professional Supportive Interventions on Nursing Home Quality Indicators project (IQUARE), a multicenter, individually tailored, nonrandomized controlled trial in NHs across southwestern France.

SETTING/PARTICIPANTS

We studied data from 5429 participants living in 175 NHs (average age, 86.1 ± 8.1 years; 73.9% women).

MEASUREMENTS

All prescriptions obtained at baseline were analyzed by a pharmacist for acetaminophen use as stand-alone or associated. Myocardial infarction (MI) and strokes were reported from participants' medical records at 18-month follow-up. Dates of death were obtained. Data collection was done through an online questionnaire at baseline and at 18 months by NH staff. Analyses were realized in our total population and a population matched on propensity score of acetaminophen intake. Six models were run for each outcome.

RESULTS

A total of 2239 participants were taking, on average, 2352 ± 993 mg of acetaminophen daily. Results for mortality were: hazard ratio (HR) = 0.97 (95% confidence interval [CI] = 0.86-1.10). No associations between acetaminophen intake and the risk of mortality or MI were found. In one of our models, acetaminophen intake was associated with a significant increased risk of stroke in diabetic subjects (OR = 3.19; 95% CI = 1.25-8.18; P = .0157). [Correction added March 16, 2019, after first publication online. In the previous sentence, "HR" was mistakenly used instead of "OR".] CONCLUSION: Despite old age, polypharmacy, and polymorbidity, acetaminophen was found safe for most, but not all, of our NH study population. Pain management in NHs is a health priority, and acetaminophen remains a good therapeutic choice as a first-line analgesic. More studies are needed on older diabetic patients.

The analgesic interaction of tramadol and morphine in rats: An isobolographic study

In order to assess possible synergistic antinociceptive interactions, the analgesic effects of intra-peritoneal tramadol and morphine administered either separately or in combination were determined using tail-flick latency test following exposure to radiant heat in rats. Groups of eight male Sprague-Dawley rats received either tramadol (3.90, 7.00, 12.50, and 22.20 mg kg^-1) and morphine (1.26, 2.25, 4.00 and 7.10 mg kg^-1) or a combination of tramadol and morphine (4 different combinations). The baseline latency was obtained before drug injection for each rat, then at 15, 30, 45, 60 and 75 min after injection. The effective dose (ED)₅₀ for either tramadol or morphine individually was 11.70 mgkg^-1 and 2.26 mg kg^-1, respectively. Based on isobolographic analysis, the ED₅₀ values obtained by drug combination were significantly less than the calculated additive values; which indicates that the co-administration of tramadol and morphine produces synergistic antinociception in the radiant heat tail-flick assay. Combination of morphine and tramadol administered intra-peritoneally can be used for the control of acute pain in rats.

Pharmacological interaction between NSAIDS with clomipramine and risperidone in mice visceral pain

Nonsteroidal anti-inflammatory drugs (NSAIDs) possess as primary action mechanism the inhibition of cyclooxygenases (COX-1, COX-2, and COX-3), thus producing a decreasing prostaglandin synthesis. This study was designed to evaluate whether the antinociception induced by NSAIDs could be modulated by clomipramine or risperidone using a chemical model of inflammatory acute visceral pain, the abdominal acetic acid induced a writhing test in mice. Dose-response curves, intraperitoneal, or intrathecal for the antinociceptive activity displayed by ketoprofen, piroxicam, nimesulide, parecoxib, and paracetamol were analyzed in order to obtain the ED₅₀ of each drug. Pretreatment of mice with either clomipramine or risperidone, increased antinociceptive potency of ketoprofen, piroxicam, nimesulide, parecoxib, and paracetamol, expressed by a decrease in the values of antinociceptive ED_50. The results that were obtained are in line with those where the inhibition of COXs provides a justification for most of the pharmacological actions. Nevertheless, several findings suggest other molecular mechanisms, among which may be mentioned, L-selecting shedding; inhibition of i-NOS; inhibition of NF-Kappa B; suppression metaloproteinasas; inhibition of ß2 integrin activation; activation of α₂ -adrenoceptor; increase of IL-1ß; upregulation IL-6. In conclusion, the data generated in this study demonstrated that risperidone and clomipramine, separately, increase antinociceptive potency of NSAIDs in a chemical model of inflammatory acute visceral tonic pain.

An integrated safety analysis of combined acetaminophen and ibuprofen (Maxigesic /Combogesic®) in adults

INTRODUCTION

Acetaminophen (APAP) and ibuprofen (IBP) are two analgesic compounds with a long history of use. Both are considered safe at recommended over-the-counter daily doses. Chronic use, high doses, or concomitant medication can produce safety risks for both drugs. APAP is associated with increased risk of hepatic injury, while IBP can produce gastric bleeding and thromboembolic events. Using a combination of APAP and IBP provides superior analgesia without transgressing daily dose limits of each individual drug.

METHODS

The present study aimed to determine if treatment with a fixed-dose combination (FDC) containing APAP and IBP results in any unexpected adverse events (AEs) and/or changes in the safety profiles of its two ingredients compared to monotherapy. The analysis will examine clinical safety data obtained from either single dose trials, multiple dose trials, a long-term exposure trial, and post-marketing surveillance data of APAP/IBP FDC tablets (Maxigesic®/Combogesic®, AFT Pharmaceuticals Ltd). The largest dataset was obtained by pooling the four randomized-controlled, multiple-dose clinical studies with either APAP 325 mg + IBP 97.5 mg (FDC 325/97.5, three tablets per dose) or APAP 500 mg + IBP 150 mg (FDC 500/150, two tablets per dose). At maximum doses, the two FDCs are bioequivalent, permitting the pooling of data for the analysis of safety.

RESULTS

A safety population of 922 patients who received full doses of either FDC, APAP alone, IBP alone, or placebo was compiled from the four studies. A total of 521 AEs were experienced with the incidence of FDC AEs similar to or below either monotherapy group or placebo. The FDC did not alter the incidence and percentage of the most common AEs, including gastrointestinal events and postoperative bleeding.

CONCLUSION

Overall, the FDC is well tolerated and has a strong safety profile at single and multiple doses with improved efficacy over monotherapy.

Analgesic efficacy of ketorolac associated with a tramadol/acetaminophen combination after third molar surgery - a randomized, triple-blind clinical trial

BACKGROUND

This study compared the efficacy of ketorolac alone versus its combination with tramadol/acetaminophen for pain control after mandibular third molar surgery.

MATERIAL AND METHODS

A randomized, triple-blind clinical trial was carried out with 52 patients divided into 2 groups: Group K+T+A (1 tablet of Ketorolac 10 mg plus and 1 capsule of Tramadol 37.5 mg/acetaminophen 325 mg) and Group K (1 tablet of Ketorolac 10 mg plus and 1 placebo capsule). The treatments were given 1 h before the surgery and was repeated 4 times per day, for 48 h. The difference in postoperative pain was assessed by 4 primary end-points: pain intensity (VAS 100mm, for 48 h), rescue medication, overall assessment and adverse effects.

RESULTS

Significant differences in pain intensity were observed in the different times (p < 0.05). The comparison of groups in each time showed significant differences only of 9 h, with lower level of pain intensity for group K+T+A (p = 0.005). The need of analgesics was higher in Group K (p < 0.001), the need of antiemetic were greater in Group K+T+A (p < 0.0001). No significant difference between groups were observed in overall assessment. The adverse effects was higher in Group K+T+A.

CONCLUSIONS

The current study showed that both ketorolac and the combination of ketorolac plus tramadol/acetaminophen showed good control of pain after the extraction of the lower third molars. Although the combination group showed lower pain at 9 h, the difference is small and not clinically relevant.

Analgesics in Small Mammals

Managing pain effectively in any species is challenging, but small mammals present particular problems. Methods of pain assessment are still under development in these species, so the efficacy of analgesic therapy cannot be evaluated fully. Methods of assessing abdominal pain are established; however, applying these can be challenging. Alternative methods, using assessment of facial expression, may be more applicable to a range of painful procedures and across species. Multimodal and preventive analgesic strategies are most likely to be effective. Although data on analgesic dose rates are limited, sufficient information is available to enable analgesia to be provided safely.

Clinical update on benefit versus risks of oral paracetamol alone or with codeine: still a good option?

BACKGROUND

After decades of worldwide use of paracetamol/acetaminophen as a popular and apparently safe prescription and over-the-counter medicine, the future role of this poorly understood analgesic has been seriously questioned by recent concerns about prenatal, cardiovascular (CV) and hepatic safety, and also about its analgesic efficacy. At the same time the usefulness of codeine in combination products has come under debate.

METHODS

Based on a PubMed database literature search on the terms efficacy, safety, paracetamol, acetaminophen, codeine and their combinations up to and including June 2016, this clinical update reviews the current evidence of the benefit and risks of oral paracetamol alone and with codeine for mild-to-moderate pain in adults, and compares the respective efficacy and safety profiles with those of nonsteroidal anti-inflammatory drugs (NSAIDs).

RESULTS

Whereas there is a clear strong association of NSAID use and gastrointestinal (GI) and CV morbidity and mortality, evidence for paracetamol with and without codeine supports the recommended use even in most vulnerable individuals, such as the elderly, pregnant women, alcoholics, and compromised GI and CV patients. The controversies and widespread misconceptions about the complex hepatic metabolism and potential hepatotoxicity have been corrected by recent reviews, and paracetamol remains the first-line nonopioid analgesic in patients with liver diseases if notes of caution are applied.

CONCLUSION

Due to its safety and tolerability profile paracetamol remained a first-line treatment in many international guidelines. Alone and with codeine it is a safe and effective option in adults, whilst NSAIDs are obviously less safe as alternatives, given the risk of potentially fatal GI and CV adverse effects.

Voluntary intake of paracetamol-enriched drinking water and its influence on the success of embryo transfer in mice

Embryo transfer (ET) in mice is a key technique in biomedical research, and is carried out mostly via surgery by transferring founder embryos into pseudo-pregnant recipient females. To cover post-operative analgesic requirements in surrogate mothers, oral self-administration of painkillers has several advantages, but its effectiveness has also been criticized as voluntary ingestion of the drug can be uncertain. Additionally, concerns about potential negative side effects of analgesics on embryo viability and development have been raised. In this regard, we investigated the impact of orally administered analgesia by comparing the outcome of ET with and without paracetamol in the drinking water (3.5mg/ml) of surrogate mothers. Water intake increased significantly when paracetamol, as a sweet-tasting formulation (children's syrup), was added to the drinking water. Measurements of paracetamol concentrations in blood serum confirmed reasonable drug uptake. Success rate of ETs and the body weight of newborn offspring were not different whether paracetamol was administered for two days after surgery or not. In conclusion, paracetamol in drinking water was consumed voluntarily in substantial doses, without detectable side-effects, by freshly operated surrogate mothers, and can therefore be recommended as a feasible method for providing analgesic treatment for surgical ET in mice.

Nonsteroidal Anti-inflammatory Drugs for Managing Postoperative Endodontic Pain in Patients Who Present with Preoperative Pain: A Systematic Review and Meta-analysis

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been commonly used to treat endodontic postoperative pain. The purpose of this study was to address the following Population, Intervention, Comparator, Outcome, Timing, Study design and setting question: in patients with preoperative pain who undergo initial orthograde endodontic treatment, what is the comparative efficacy of NSAIDS compared with non-narcotic analgesics or placebo in reducing postoperative pain and the incidence of adverse events.

METHODS

Ovid MEDLINE (1946-December 15, 2015), the Cochrane Database of Systematic Reviews (2005-December 15, 2015), and the Cochrane Central Register of Controlled Trials (to December 15, 2015) were searched using included drugs, indications, and study designs as search terms. Hand searches in texts were also conducted. Two independent reviewers assessed eligibility for inclusion, extracted data, and assessed quality using the risk of bias tool. L'Abbe plots were used for qualitative review. Where applicable, meta-analysis was conducted on the pooled effect size (ES).

RESULTS

Two thousand two hundred eighty-four studies were identified through the database searches; 405 full-text articles were assessed. Fifteen articles met the inclusion criteria; qualitative analysis revealed all studies had a moderate to high risk of bias. Ibuprofen was the most studied NSAID. The L'Abbe plots showed that NSAIDS are effective at relieving postoperative endodontic pain overall. Meta-analysis showed that ibuprofen 600 mg is more effective than placebo at 6 hours postoperatively (ES = 10.50, P = .037), and ibuprofen 600 mg + acetaminophen 1000 mg combination is more effective than placebo (ES = 34.89, P = .000) but not significantly different than ibuprofen (ES = 13.94, P = .317). Five studies reported patients experiencing adverse events such as drowsiness, dizziness, nausea, and emesis; 2 studies reported that patients experienced no adverse events.

CONCLUSIONS

A combination of ibuprofen 600 mg and acetaminophen 1000 mg is more effective than placebo but not significantly different than ibuprofen 600 mg at 6 hours postoperatively. Ibuprofen 600 mg is more effective than placebo at 6 hours postoperatively; however, there are insufficient data to recommend the most effective NSAID, dose amount, or dose interval for the relief of postoperative endodontic pain of longer duration in patients with preoperative pain.

Evaluation of the Analgesic Efficacy of Dexketoprofen Added to Paracetamol

OBJECTIVE

Multimodal analgesic methods are preferred for the treatment of postoperative pain; as a result, the additive effects of analgesics are provided while probable side effects are avoided. The current study aimed to compare the effects of the combination of dexketoprofen and paracetamol with regard to postoperative pain therapy.

METHODS

Ninety-six patients who underwent non-malignant gynaecological laparotomy operations were included in this study. Patients were randomized into 3 groups. Group D received 50 mg intravenous dexketoprofen 15 minutes before the end of the operation and 8 and 16 hours after the operation. Group P received 1 g intravenous paracetamol and Group DP received the combination of 500 mg paracetamol and 25 mg dexketoprofen at the same time intervals. All patients received morphine infusion after operation. Total morphine consumption at 24 hours, visual analog scale, patient satisfaction and side effects were investigated.

RESULTS

Comparison of the visual analog scale scores revealed that the Group DP presented lower scores at 24th hours compared to the other groups; and the difference between Group DP and Group D was statistically significant. Total morphine consumption was not significantly different between the three groups. The minimum number of side effects was observed in the Group DP.

CONCLUSION

Co-administration of paracetamol, dexketoprofen and morphine provided good analgesia and fewer side effects in gynaecological abdominal surgery.

Evaluation of herbal antimalarial MAMA decoction-amodiaquine combination in murine malaria model

CONTEXT

Co-administration of amodiaquine with MAMA decoction (MD), an herbal antimalarial drug comprising the leaves of Mangifera indica L. (Anacardiaceae), Alstonia boonei De Wild (Apocynaceae), Morinda lucida Benth (Rubiaceae) and Azadirachta indica A. Juss (Meliaceae) was investigated. The practice of concurrent administration of herbal medicines with orthodox drugs is currently on the increase globally.

OBJECTIVE

The study was designed to investigate the possible enhancement of the antimalarial potency as well as possible herb-drug interaction resulting from concurrent administration of MAMA decoction with amodiaquine (AQ).

MATERIALS AND METHODS

Combinations of MD with AQ were investigated in chloroquine (CQ)-sensitive Plasmodium berghei NK 65 in varying oral doses (mg/kg) at: sub-therapeutic [MD30 + AQ1.25], therapeutic [MD120 + AQ10] and median effective [MD40 + AQ3.8], using chemosuppressive and curative antimalarial test models. Secondly, P. berghei ANKA (CQ-resistant)-infected mice were orally treated with MD 120, 240, [MD120 + AQ10] and [MD240 + AQ10] mg/kg, using both models. The survival times of mice were monitored for 28 d.

RESULTS

ED50 values of MD and AQ were 48.8 and 4.1 mg/kg, respectively. A total parasite clearance of CQ-sensitive P. berghei NK65 was obtained with the therapeutic combination dose in the curative test giving an enhanced survival time. In CQ-resistant P. berghei ANKA-infected mice, [MD120 + AQ10] and [MD240 + AQ10] mg/kg gave comparable activities with AQ (10 mg/kg) in both models.

CONCLUSION

The therapeutic combination dose gave total parasite clearance of CQ-sensitive P. berghei NK65, whereas none of the doses tested showed notable activity against CQ-resistant P. berghei ANKA.

Inhibitory Mechanism of Apigenin on α-Glucosidase and Synergy Analysis of Flavonoids

Inhibition of α-glucosidase activity may suppress postprandial hyperglycemia. The inhibition kinetic analysis showed that apigenin reversibly inhibited α-glucosidase activity with an IC50 value of (10.5 ± 0.05) × 10(-6) mol L(-1), and the inhibition was in a noncompetitive manner through a monophasic kinetic process. The fluorescence quenching and conformational changes determined by fluorescence and circular dichroism were due to the formation of an α-glucosidase-apigenin complex, and the binding was mainly driven by hydrophobic interactions and hydrogen bonding. The molecular simulation showed that apigenin bound to a site close to the active site of α-glucosidase, which may induce the channel closure to prevent the access of substrate, eventually leading to the inhibition of α-glucosidase. Isobolographic analysis of the interaction between myricetin and apigenin or morin showed that both of them exhibited synergistic effects at low concentrations and tended to exhibit additive or antagonistic interaction at high concentrations.

The Effects of Diclofenac Suppository and Intravenous Acetaminophen and their Combination on the Severity of Postoperative Pain in Patients Undergoing Spinal Anaesthesia During Cesarean Section

INTRODUCTION

The main tasks of postoperative care are postoperative pain and complications control which play an important role in accelerating the recovery of patient's general condition.

AIM

This study was performed in order to compare the effects of diclofenac suppository, intravenous acetaminophen and their combination on the severity of postoperative pain in patients undergoing spinal anaesthesia for cesarean section in Sayyad Shirazi teaching Hospital, Gorgon, Iran.

MATERIALS AND METHODS

This was a double-blind clinical trial on 90 patients undergoing cesarean section. The patients were randomly divided into three groups, group A: 100 mg diclofenac suppository, group B: 1000 mg intravenous acetaminophen, group C: 100 mg diclofenac suppository and 500 mg intravenous acetaminophen. The same spinal anaesthesia circumstances were applied for all the participants. At the end of surgery, pain severity was assessed according to VAS scale at different times. Data were then analysed by SPSS 18 statistical software.

RESULTS

The mean age of participants was (28.27±6.07). There was significant difference between the mean pain scores of the three groups before the intervention (p=0.018), which was considered as co-variate. This difference was more notable between the combination of acetaminophen - diclofenac group and diclofenac alone. After the intervention, significant difference was observed in mean pain severity between acetaminophen group and the combination group and also between diclofenac and the combination group. During the study, the least mean pain severity was found in the combination group and the highest was observed in the diclofenac group.

CONCLUSION

Results of this study indicates a significant effect of concomitant use of intravenous acetaminophen and diclofenac suppository on pain severity reduction and reducing the need for repeated doses of narcotics and prolonging the postoperative analgesia.

Subcutaneous meloxicam suspension pharmacokinetics in mice and dose considerations for postoperative analgesia

Meloxicam is a cyclooxygenase (COX) inhibitor with a higher selectivity for cyclooxygenase‐2 (COX‐2) than for cyclooxygenase‐1 (COX‐1). In the laboratory setting, this nonsteroidal anti‐inflammatory drug (NSAID) is commonly selected for analgesia in mice and administered every 24 h. This study characterizes the plasma concentration achieved from a dose of 1.6 mg/kg of meloxicam administered once every 24 h subcutaneously for 72 h in male and female C57BL/6 mice. These values were compared, over time, to reference COX‐2 inhibition constants for meloxicam. No significant differences in trough plasma concentrations were noted between genders. The plasma concentrations were below the COX‐2 IC₅₀ after 12 h. To maintain a plasma concentration at or above the COX‐2 whole blood IC_50, the study results suggest an administration frequency of every 12 h when using a dose of 1.6 mg/kg in C57BL/6 mice.