Gabapentin: pharmacology and its use in pain management

6-Methoxyflavone antagonizes chronic constriction injury and diabetes associated neuropathic nociception expression

Neuropathy is a disturbance of function or a pathological change in nerves causing poor health and quality of life. A proportion of chronic pain patients in the community suffer persistent neuropathic pain symptoms because current drug therapies may be suboptimal so there is a need for new therapeutic modalities. This study investigated the neuroprotective flavonoid, 6-methoxyflavone (6MF), as a potential therapeutic agent and gabapentin as the standard comparator, against neuropathic models. Thus, neuropathic-like states were induced in Sprague-Dawley rats using sciatic nerve chronic constriction injury (CCI) mononeuropathy and systemic administration of streptozotocin (STZ) to induce polyneuropathy. Subsequent behaviors reflecting allodynia, hyperalgesia, and vulvodynia were assessed and any possible motoric side-effects were evaluated including locomotor activity, as well as rotarod discoordination and gait disruption. 6MF (25-75 mg/kg) antagonized neuropathic-like nociceptive behaviors including static- (pressure) and dynamic- (light brushing) hindpaw allodynia plus heat/cold and pressure hyperalgesia in the CCI and STZ models. 6MF also reduced static and dynamic components of vulvodynia in the STZ induced polyneuropathy model. Additionally, 6MF reversed CCI and STZ suppression of locomotor activity and rotarod discoordination, suggesting a beneficial activity on motor side effects, in contrast to gabapentin. Hence, 6MF possesses anti-neuropathic-like activity not only against different nociceptive modalities but also impairment of motoric side effects.

A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled 14-Week Study of Mirogabalin in Chinese Patients with Diabetic Peripheral Neuropathic Pain

INTRODUCTION

There is no approved effective drug for diabetic peripheral neuropathic pain (DPNP) in China. Gabapentinoids including mirogabalin have shown promise, although data in Chinese patients are scarce.

METHODS

This phase 3, multicenter, randomized, double-blind, placebo-controlled trial investigated the efficacy and safety of mirogabalin for treating DPNP in China. Mirogabalin was administered at 5 mg twice daily for the first week and uptitrated to 15 mg twice daily for a total duration of 14 weeks. The primary efficacy endpoint was the change from baseline in weekly average daily pain score (ADPS) at week 14; secondary endpoints included the ADPS responder rate, Short-Form McGill Pain Questionnaire visual analogue scale score, patient global impression of change (PGIC), average daily sleep interference score (ADSIS), EuroQol 5-dimensions 5-levels (EQ-5D-5L), and incidence of treatment-emergent adverse events (TEAEs).

RESULTS

Of 393 patients (mirogabalin, n = 196; placebo n = 197), the mean age was 58.2 years (mirogabalin, 58.7 years; placebo, 57.7 years) and 54.2% were male (mirogabalin, 56.1%; placebo, 52.3%). Mirogabalin elicited a greater change from baseline in the weekly ADPS vs. placebo at week 14: least-squares mean difference (95% confidence interval) vs. placebo - 0.39 (- 0.74, - 0.04), p = 0.0301. PGIC, ADSIS, and EQ-5D-5L data reflected significantly better improvements for patients receiving mirogabalin vs. placebo. The incidence of TEAEs was 75.0% and 75.1% in the mirogabalin and placebo groups, respectively. Most TEAEs were mild or moderate, and the incidence of TEAEs leading to treatment discontinuation was 2.6% in the mirogabalin group and 1.5% in the placebo group.

CONCLUSIONS

Although the effect size of mirogabalin was reduced due to the placebo effect, mirogabalin is a safe and effective treatment option for Chinese patients with DPNP.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04094662.

An analysis of suicidal and self-injurious behavior reports with antiseizure medications in the FDA adverse event database

BACKGROUND

Pharmacovigilance systems such as the FDA Adverse Event Reporting System (FAERS), are established models for adverse event surveillance that may have been missed during clinical trials. We aimed to analyze twenty-five anti-seizure medications (ASMs) in FAERS to assess for increased reporting of suicidal and self-injurious behavior.

METHODS

Twenty-five ASMs were analyzed: brivaracetam, cannabidiol, carbamazepine, clobazam, clonazepam, diazepam, eslicarbazepine, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, phenobarbital, phenytoin, pregabalin, primidone, rufinamide, stiripentol, tiagabine, topiramate, valproate, vigabatrin, zonisamide. Reports of "suicidal and self-injurious behavior" were collected from January 1, 2004, to December 31, 2020, using OpenVigil 2.1 tool with indication as "Epilepsy". Relative reporting ratio, proportional reporting ratio, and reporting odds ratio were calculated utilizing all other drug reports for epilepsy patients as a control.

RESULTS

Significant relative operating ratio, ROR (greater than 1, p<0.05) were observed for diazepam (2.909), pregabalin (2.739), brivaracetam (2.462), gabapentin (2.185), clonazepam (1.649), zonisamide (1.462), lacosamide (1.333), and levetiracetam (1.286).

CONCLUSIONS

Of the 25 ASMs that were analyzed in this study, 4 (16%) were identified to have been linked with a likely true adverse event. These drugs included diazepam, brivaracetam, gabapenetin, and pregabalin. Although several limitations are present with the FAERS database, it is imperative to closely monitor patient comorbidities for increased risk of suicidality with the use of several ASMs.

A comprehensive update on the ADMET considerations for α2δ calcium channel ligand medications for treating restless legs syndrome

INTRODUCTION

Restless legs syndrome/Willis-Ekbom disease (RLS/WED) is a sleep-related sensory-motor disorder associated with poor sleep quality and impaired daily functioning. In patients affected by chronic RLS/WED, a pharmacological therapy is recommended. International guidelines suggest to start the treatment with a α2δ calcium channel ligand in most cases, unless contraindicated.

AREAS COVERED

The present review is based on an extensive Internet and PubMed search from 1986 to 2024. Our purpose is to describe the absorption, distribution, metabolism, and toxicology (ADMET) of the α2δ ligands, with common consideration for the therapeutic class, specificities of different compounds, efficacy, and safety in relation to other treatment options.

EXPERT OPINION

α2δ ligands are quite similar in their ADMET profiles, sharing most of the pharmacokinetics and potential adverse effects. However, we highlight the linear kinetic of gabapentin enacarbil and pregabalin, differently from gabapentin. α2δ ligands are safe and effective for the treatment of RLS/WED. Additional benefits can be obtained in comorbid insomnia, chronic pain syndromes, history of impulse control disorder, and comorbid anxiety. The use of α2δ ligands is associated with poor risk of augmentation. We still need new long-term safe and effective treatments, which could be developed along with our knowledge of RLS/WED pathophysiology.

Direct Formation of Amide-Linked C-Glycosyl Amino Acids and Peptides via Photoredox/Nickel Dual Catalysis

Glycoproteins account for numerous biological processes including those associated with diseases and infections. The advancement of glycopeptides has emerged as a promising strategy for unraveling biological pathways and discovering novel medicines. In this arena, a key challenge arises from the absence of efficient synthetic strategies to access glycopeptides and glycoproteins. Here, we present a highly concise approach to bridging saccharides with amino acids and peptides through an amide linkage. Our amide-linked C-glycosyl amino acids and peptides are synthesized through cooperative Ni-catalyzed and photoredox processes. The catalytic process generates a glycosyl radical and an amide carbonyl radical, which subsequently combine to yield the C-glycosyl products. The saccharide reaction partners encompass mono-, di-, and trisaccharides. All 20 natural amino acids, peptides, and their derivatives can efficiently undergo glycosylations with yields ranging from acceptable to high, demonstrating excellent stereoselectivities. As a substantial expansion of applications, we have shown that simple C-glycosyl amino acids can function as versatile building units for constructing C-glycopeptides with intricate spatial complexities.

Role of Gabapentin in Traumatic Brain Injury: A Prospective Comparative Study

Background

Traumatic brain injury (TBI) is a major cause of mortality among young individuals, accounting for 65% of deaths in road traffic accidents. Paroxysmal sympathetic hyperactivity (PSH) is a common syndrome associated with TBI. This study represents the first prospective investigation aimed at assessing the impact of gabapentin on TBI patients, focusing on the prevention of secondary brain injury and brain edema while enhancing the Glasgow Coma Scale (GCS).

Materials and methods

The study was conducted from September 2019 to July 2021 after receiving ethical committee approval. It included adult ICU patients (≥18 years) with moderate and severe GCS. Patients below 18 years, death within 48 hours, non-consenting, pregnant females, and individuals allergic to gabapentin were excluded from the study. Patients were randomly allocated in two groups: study group received 300 mg of gabapentin orally twice daily and control group received multivitamin tablets twice daily. The treatment period spanned 2 weeks. Follow-up occurred in the ICU and continued for up to 3 months post-discharge, including telephonic conversations.

Results

About 60 patients were involved for analysis. Significant differences were found in GCS change from admission to discharge, Glasgow Outcome Scale (GOS) at 30 and 90 days, PSH episodes, and sedation bolus per day. Glasgow Coma Scale change was 53% in the study group compared with 25% in the control group (p = 0.009). Mortality was significantly lower in the study group. Glasgow Outcome Scale change between 30 and 90 days showed a 25% improvement in cases and no change in controls (p = 0.001).

Conclusion

This pioneering study underscores the potential of gabapentin in managing traumatic brain injuries.

How to cite this article

Singh R, Ambasta S, Bais PS, Azim A, Kumar S, Upreti B, et al. Role of Gabapentin in Traumatic Brain Injury: A Prospective Comparative Study. Indian J Crit Care Med 2024;28(2):120-125.

Protein Kinase C (PKC)-mediated TGF-β Regulation in Diabetic Neuropathy: Emphasis on Neuro-inflammation and Allodynia

According to the World Health Organization (WHO), diabetes has been increasing steadily over the past few decades. In developing countries, it is the cause of increased morbidity and mortality. Diabetes and its complications are associated with education, occupation, and income across all levels of socioeconomic status. Factors, such as hyperglycemia, social ignorance, lack of proper health knowledge, and late access to medical care, can worsen diabetic complications. Amongst the complications, neuropathic pain and inflammation are considered the most common causes of morbidity for common populations. This review is focused on exploring protein kinase C (PKC)-mediated TGF-946; regulation in diabetic complications with particular emphasis on allodynia. The role of PKC-triggered TGF-946; in diabetic neuropathy is not well explored. This review will provide a better understanding of the PKC-mediated TGF-946; regulation in diabetic neuropathy with several schematic illustrations. Neuroinflammation and associated hyperalgesia and allodynia during microvascular complications in diabetes are scientifically illustrated in this review. It is hoped that this review will facilitate biomedical scientists to better understand the etiology and target drugs effectively to manage diabetes and diabetic neuropathy.

Safety and Efficacy of Gabapentin for Pain in Pediatric Patients: A Systematic Review

CONTEXT

Gabapentin has shown benefits for a variety of pain etiologies in adult patients, with off-label use as an adjunctive agent in pediatric patients occurring more frequently.

OBJECTIVES

To summarize the studies which evaluate safety and efficacy of gabapentin for the treatment of pediatric pain.

DATA SOURCES

A systematic review of the literature was conducted via PubMed query with controlled vocabulary and key terms using indexed medical subject heading.

STUDY SELECTION

Prospective studies published between January 1, 2000, and July 1, 2023, were selected utilizing a predetermined exclusion criteria independently by 2 authors, with a third independent author available for discrepancies.

DATA EXTRACTION

Data extraction was performed by 2 authors independently to include study design, patient population and characteristics, drug dosing, and outcomes. Studies were then assessed for their independent risk of bias utilizing the Grading of Recommendations, Assessment, Development, and Evaluations approach to risk of bias.

RESULTS

A total of 11 studies describing 195 pediatric patients who received gabapentin were included. Of the 11 studies, 9 were randomized controlled trials, 1 was a prospective multicenter study, and 1 was an open-label pilot study.

CONCLUSIONS

Heterogeneity of pain type and gabapentin dosing regimens within the included studies made conclusions difficult to quantify. Efficacy likely depends significantly on etiology of pain; however, per these studies, gabapentin is likely safe to use for a variety of pediatric patient populations as a multimodal agent.

A comparison of the preemptive effects of oral pregabalin and gabapentin on acute postoperative sedation and complications in patients undergoing lumbar spine surgery

BACKGROUND

Gabapentinoids are often administered preoperatively, as they have been shown to reduce postoperative opioid consumption and pain scores however sedation has always been a concern because of sedative side effect.

OBJECTIVE

This study was intended to compare oral gabapentin versus oral pregabalin sedative effects and complications in patients undergoing lumbar spine surgery under general anaesthesia.

METHODS

This study was a true experimental randomised, placebo-controlled, prospective study, conducted at Rafedia Government Surgical Hospital in Nablus, Palestine. The sample consisted of 60 male and female patients undergoing elective lumbar spine surgeries in the department of neurology and aged from 18 to 70 years. The patients were divided into three groups (20 patients each): The pregabalin 150mg group, the gabapentin group and the placebo group.

FINDINGS

Nearly 51.7% of the participants reported that they experienced a feeling of nausea or vomiting after the operation. There were statistically significant differences (p-value = 0.008) between the groups in how often complications happen after surgery.

CONCLUSIONS

Preemptive pregabalin (150mg) was established to have a more sedative effect and lowered complications than gabapentin (300mg).

Beyond benzodiazepines: a meta-analysis and narrative synthesis of the efficacy and safety of alternative options for alcohol withdrawal syndrome management

PURPOSE

To compare the efficacy and safety of non-benzodiazepines (non-BZDs) to benzodiazepines (BZDs) in the treatment of alcohol withdrawal syndrome (AWS).

METHODS

For relevant literature, Google Scholar, PubMed, Embase, OVID MEDLINE, EBSCO, Cochrane Central Registry of Controlled Trials, Web of Science, and Scopus were searched. Randomized control trials (RCTs) were included, omitted were nonblinded trials, blinded trials that were not randomized, and open-label studies. The Effective Public Health Practice Project Quality Assessment was used to assess the trial's quality. A meta-analysis and a narrative synthesis were carried out.

RESULTS

Twenty non-BZDs and five BZDs were investigated in thirty RCTs. Meta-analysis favored gabapentin over chlordiazepoxide and lorazepam (d = 0.563, p < 0.001) and carbamazepine over oxazepam and lorazepam (d = 0.376, p = 0.029), for reducing Clinical Institute Withdrawal Assessment for Alcohol-Revised (CIWA-Ar) scale scores. Eleven non-BZDs fared better than BZDs for reducing CIWA-Ar, Total Severity Assessment, Selective Severity Assessment, Borg and Weinholdt, and Gross Rating Scale for Alcohol Withdrawal scores. Eight non-BZDs outmatched BZDs regarding autonomic, motor, awareness, and psychiatric symptoms. Sedation and fatigue were prevalent in BZDs, while seizures were prevalent in non-BZDs.

CONCLUSION

For AWS treatments, non-BZDs are superior to or equally effective as BZDs. Non-BZD adverse events warrant further investigation. Agents that inhibit gated ion channels are promising candidates.

PROTOCOL REGISTRATION

PROSPERO CRD42022384875.

New GABA-Targeting Therapies for the Treatment of Seizures and Epilepsy: II. Treatments in Clinical Development

The inhibitory neurotransmitter γ-aminobutyric acid (GABA) plays an important role in the modulation of neuronal excitability, and a disruption of GABAergic transmission contributes to the pathogenesis of some seizure disorders. Although many currently available antiseizure medications do act at least in part by potentiating GABAergic transmission, there is an opportunity for further research aimed at developing more innovative GABA-targeting therapies. The present article summarises available evidence on a number of such treatments in clinical development. These can be broadly divided into three groups. The first group consists of positive allosteric modulators of GABAA receptors and includes Staccato® alprazolam (an already marketed benzodiazepine being repurposed in epilepsy as a potential rescue inhalation treatment for prolonged and repetitive seizures), the α2/3/5 subtype-selective agents darigabat and ENX-101, and the orally active neurosteroids ETX155 and LPCN 2101. A second group comprises two drugs already marketed for non-neurological indications, which could be repurposed as treatments for seizure disorders. These include bumetanide, a diuretic agent that has undergone clinical trials in phenobarbital-resistant neonatal seizures and for which the rationale for further development in this indication is under debate, and ivermectin, an antiparasitic drug currently investigated in a randomised double-blind trial in focal epilepsy. The last group comprises a series of highly innovative therapies, namely GABAergic interneurons (NRTX-001) delivered via stereotactic cerebral implantation as a treatment for mesial temporal lobe epilepsy, an antisense oligonucleotide (STK-001) aimed at upregulating NaV1.1 currents and restoring the function of GABAergic interneurons, currently tested in a trial in patients with Dravet syndrome, and an adenoviral vector-based gene therapy (ETX-101) scheduled for investigation in Dravet syndrome. Another agent, a subcutaneously administered neuroactive peptide (NRP2945) that reportedly upregulates the expression of GABAA receptor α and β subunits is being investigated, with Lennox-Gastaut syndrome and other epilepsies as proposed indications. The diversity of the current pipeline underscores a strong interest in the GABA system as a target for new treatment development in epilepsy. To date, limited clinical data are available for these investigational treatments and further studies are required to assess their potential value in addressing unmet needs in epilepsy management.

Multimodal analgesia did not improve post-operative pain scores, reduce opioid consumption or reduce length of stay following hip arthroscopy

PURPOSE

To determine whether different regimens of multimodal analgesia will reduce postoperative pain scores, opioid consumption, costs and hospital length-of-stay following hip arthroscopy.

METHODS

From 2018 to 2021, 132 patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) were included in this prospective, single-center randomized controlled trial. Patients were randomized into four treatment groups: (1) Group 1-Control: opioid medication (oxycodone-acetaminophen 5 mg/325 mg, 1-2 tabs q6H as needed), Heterotopic ossification prophylaxis-Naprosyn 500 mg twice daily × 3 weeks); (2) Group 2-Control + postoperative sleeping aid (Zopiclone 7.5 mg nightly × 7 days); (3) Group 3-Control + preoperative and postoperative Gabapentin (600 mg orally, 1 h preoperatively; 600 mg postoperatively, 8 h following pre-op dose); (4) Group 4-Control + pre-medicate with Celecoxib (400 mg orally, 1 h preoperatively) The primary outcome was pain measured with a visual analog scale, monitored daily for the first week and every other day for 6 weeks. Secondary outcomes included opioid consumption, healthcare resource use, and hospital length of stay.

RESULTS

Patient characteristics were similar between groups. There were no statistically significant differences in pain scores between groups at any timepoint after adjusting for intra-operative traction time, intra-operative opioid administration and preoperative pain scores (p > 0.05). There were also no significant differences in the number of days that opioids were taken (n.s.) and the average daily morphine milligram equivalents consumed (n.s.). Similarly, there were no statistically significant differences in length of stay in the experimental groups, compared with the control group (n.s.). Finally, there were no differences in cost between groups (n.s.).

CONCLUSION

The routine use of Zopiclone, Celecoxib and Gabapentin did not improve postoperative pain control or reduce length-of-stay following hip arthroscopy. Therefore, these medications are not recommended for routine postoperative pain control following hip arthroscopy.

LEVEL OF EVIDENCE

l.

Research trends and hotspots of neuropathic pain in neurodegenerative diseases: a bibliometric analysis

Background

Neuropathic pain is caused by a neurological injury or disease and can have a significant impact on people's daily lives. Studies have shown that neuropathic pain is commonly associated with neurodegenerative diseases. In recent years, there has been a lot of literature on the relationship between neuropathic pain and neurodegenerative diseases. However, bibliometrics is rarely used in analyzing the general aspects of studies on neuropathic pain in neurodegenerative diseases.

Methods

The bibliometric analysis software CiteSpace and VOSviewer were used to analyze the knowledge graph of 387 studies in the Science Citation Index Expanded of the Web of Science Core Collection Database.

Results

We obtained 2,036 documents through the search, leaving 387 documents after culling. 387 documents were used for the data analysis. The data analysis showed that 330 papers related to neuropathic pain in neurodegenerative diseases were published from 2007-2022, accounting for 85.27% of all published literature. In terms of contributions to the scientific study of neuropathic pain, the United States is in the top tier, with the highest number of publications, citations, and H-indexes.

Conclusion

The findings in our study may provide researchers with useful information about research trends, frontiers, and cooperative institutions. Multiple sclerosis, Parkinson's disease, and Alzheimer's disease are the three most studied neurodegenerative diseases. Among the pathological basis of neurodegenerative diseases, microglia-regulated neuroinflammation is a hot research topic. Deep brain stimulation and gamma knife radiosurgery are two popular treatments.

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.

Gabapentin: Clinical Use and Pharmacokinetics in Dogs, Cats, and Horses

Gabapentin is an anticonvulsant drug, which presents an established clinical efficacy in human patients for the management of refractory partial seizures, secondarily generalized tonic-clonic seizures, and for the control of chronic neuropathic pain. Gabapentin was synthesized as a structural analogue of the inhibitory neurotransmitter GABA, with GABA-mimetic effects, able to cross the blood-brain barrier. In veterinary medicine, is extra-label used in combination with other treatments to control seizures when other drugs are no longer effective or become toxic or for neuropathic pain treatment and anxiety. This review aimed to clarify gabapentin use and pharmacokinetic aspects to promote conscious use in dogs, cats, and horses. In dogs, gabapentin was beneficial in the treatment of epilepsy, as well as chronic, neuropathic, and post-operative pain, as well as anxiety. In cats, it showed efficacy in post-ovariohysterectomy-related pain and in anxiety management. In horses, gabapentin has been administered as an analgesic for chronic pain management. In conclusion, when used in combination with other drugs, gabapentin can be considered an interesting therapeutic option for the treatment of neuropathic diseases and analgesia in postoperative and chronic pain. However, despite its beneficial use in different clinical settings, further trials and pharmacokinetic studies are needed for the definition of an effective dosage regimen through proper pharmacokinetic/pharmacodynamic correlation in dogs, cats, and horses.

Antiseizure Medication-Induced Alopecia: A Literature Review

Background: Adverse effects of antiseizure medications (ASMs) remain one of the major causes of non-adherence. Cosmetic side effects (CSEs) are among the most commonly reported side effects of ASMs. In this context, alopecia is one of the CSEs that has a high intolerance rate leading to poor therapeutical compliance. Methods: We performed a literature review concerning alopecia as a secondary effect of ASMs. Results: There are 1656 individuals reported with ASM-induced alopecia. Valproate (983), lamotrigine (355), and carbamazepine (225) have been extensively reported. Other ASMs associated with alopecia were cenobamate (18), levetiracetam (14), topiramate (13), lacosamide (7), vigabatrin (6), phenobarbital (5), gabapentin (5), phenytoin (4), pregabalin (4), eslicarbazepine (3), brivaracetam (2), clobazam (2), perampanel (2), trimethadione (2), rufinamide (2), zonisamide (2), primidone (1), and tiagabine (1). There were no reports of oxcarbazepine and felbamate with drug-induced alopecia. Hair loss seen with ASMs was diffuse and non-scarring. Telogen effluvium was the most common cause of alopecia. A characteristic feature was the reversibility of alopecia after ASM dose adjustment. Conclusions: Alopecia should be considered one important adverse effect of ASMs. Patients reporting hair loss with ASM therapy should be further investigated, and specialist consultation is recommended.

Prioritization of pharmaceuticals and personal care products in the surface waters of Korea: Application of an optimized risk-based methods

The occurrence of PPCPs in aquatic environments and their potential adverse effects on aquatic organisms have raised worldwide concerns. To address this issue, a study was conducted to analyze 137 selected PPCPs in Korean surface waters, and an optimized risk-based prioritization was performed. The results revealed that 120 PPCPs were detected, with 98 quantified at concentrations ranging from few ng/L to 42,733 ng/L for metformin. The 95% upper confidence limit (UCL95) of the mean value of the measured environmental concentration (MEC) for Metformin was about eight times higher than the second highest compound, dimethyl phthalate, indicating that antidiabetic groups had the highest concentration among the therapeutic groups. An optimized risk-based prioritization was then assessed based on the multiplication of two indicators, the Frequency of Exceedance and the Extent of Exceedance of Predicted No-Effect Concentrations (PNECs), which can be calculated using the traditional risk quotient (RQ) approach. The study found that clotrimazole had the highest risk quotient value of 17.4, indicating a high risk to aquatic organisms, with seven and 13 compounds showing RQ values above 1 and 0.1, respectively. After considering the frequency of exceedance, clotrimazole still had the highest novel risk quotient (RQ_f) value of 17.4, with 99.6% of its MECs exceeding PNECs. However, the number of compounds with RQ_f values above 1 decreased from seven to five, with cetirizine and flubendazole being excluded. Furthermore, only 10 compounds exhibited RQ_f values above 0.1. The study also observed significant differences in the results between risk-based and exposure-based prioritization methods, with only five compounds, cetirizine, olmesartan, climbazole, sulfapyridine, and imidacloprid, identified in both methods. This finding highlights the importance of considering multiple methods for prioritizing chemicals, as different approaches may yield different results.

Ketoprofen, lysine and gabapentin co-crystal magnifies synergistic efficacy and tolerability of the constituent drugs: Pre-clinical evidences towards an innovative therapeutic approach for neuroinflammatory pain

Chronic pain is an enormous public health concern, and its treatment is still an unmet medical need. Starting from data highlighting the promising effects of some nonsteroidal anti-inflammatory drugs in combination with gabapentin in pain treatment, we sought to combine ketoprofen lysine salt (KLS) and gabapentin to obtain an effective multimodal therapeutic approach for chronic pain. Using relevant in vitro models, we first demonstrated that KLS and gabapentin have supra-additive effects in modulating key pathways in neuropathic pain and gastric mucosal damage. To leverage these supra-additive effects, we then chemically combined the two drugs via co-crystallization to yield a new compound, a ternary drug-drug co-crystal of ketoprofen, lysine and gabapentin (KLS-GABA co-crystal). Physicochemical, biodistribution and pharmacokinetic studies showed that within the co-crystal, ketoprofen reaches an increased gastrointestinal solubility and permeability, as well as a higher systemic exposure in vivo compared to KLS alone or in combination with gabapentin, while both the constituent drugs have increased central nervous system permeation. These unique characteristics led to striking, synergistic anti-nociceptive and anti-inflammatory effects of KLS-GABA co-crystal, as well as significantly reduced spinal neuroinflammation, in translational inflammatory and neuropathic pain rat models, suggesting that the synergistic therapeutic effects of the constituent drugs are further boosted by the co-crystallization. Notably, while strengthening the therapeutic effects of ketoprofen, KLS-GABA co-crystal showed remarkable gastrointestinal tolerability in both inflammatory and chronic neuropathic pain rat models. In conclusion, these results allow us to propose KLS-GABA co-crystal as a new drug candidate with high potential clinical benefit-to-risk ratio for chronic pain treatment.

Provider-directed analgesia for dental pain

INTRODUCTION

Extraction of impacted molar teeth is a common procedure performed by oral surgeons and general dentists, with postoperative pain being a significant adverse event post-surgery. If mismanaged, pain can lead to complications that impact oral and systemic health. The current scourge of the opioid epidemic has ushered in a new era of provider-directed analgesic (PDA) therapy in dentistry.

AREAS COVERED

This article provides an in-depth review on the major pharmacological and therapeutic properties of established and alternative analgesics used to manage dental pain.

EXPERT OPINION

Substantial evidence-based literature shows combination of a non-steroidal anti-inflammatory drug (NSAID; e.g. ibuprofen) and acetaminophen provides superior pain relief than single-agent or combination opioid regimens. However, there are clinical scenarios (e.g. severe pain) when short-course opioid prescription is appropriate in select patients, in which a 2-3-day treatment duration is typically sufficient. Alternative agents (e.g. caffeine, gabapentin, phytotherapies), typically in combination with established agents, can mitigate postoperative dental pain. Some evidence suggests preemptive therapies (e.g. corticosteroids, NSAIDs) reduce amounts of postsurgical analgesic consumption and might lessen opioid prescription burden. In summary, this comprehensive review provides an opportune update on the evolving landscape of pharmacotherapy for acute postsurgical dental pain, informing best practices for PDA in the dental setting.

Gabapentin alleviates myocardial ischemia-reperfusion injury by increasing the protein expression of GABAARδ

Gabapentin is a commonly used analgesic in the clinic to reduce opioid consumption. It is well known that gabapentin can reduce cerebral ischemia-reperfusion injury (IRI). However, it remains unclear whether gabapentin can reduce myocardial IRI. Before the performance of myocardial ischemia and reperfusion (I/R), rats received gabapentin without or with an intravenous injection of PI3K inhibitor (LY294002), or an intraspinal injection of lentivirus-mediated GABA_ARδ-shRNA. The myocardial IRI were evaluated by calculating the infarction area, arrhythmia score and myocardial apoptosis. The activity of PI3K/Akt and the expression of GABA_ARδ were quantified by western blotting. The effect of gabapentin on myocardial I/R was further demonstrated in vitro by establishing oxygen-glucose deprivation and reoxygenation in cardiomyocytes. After I/R in vivo, there were significant increases in infarction area, arrhythmia and Bax protein expression in the myocardium, as well as a decrease of GABA_ARδ in the spinal cord. Meanwhile, I/R also decreased the protein expression of PI3K/Akt and Bcl-2. Gabapentin pretreatment successfully attenuated IRI including reducing the myocardial infarction area and apoptosis. This effect was abolished by both the systemic inhibition of PI3K/Akt and the intraspinal suppression of GABA_ARδ. However, gabapentin pretreatment failed to prevent cellular injury induced by OGD/R in cardiomyocytes. Therefore, the myocardial protective effect of gabapentin may be attributed to activating PI3K/Akt in the myocardium and upregulating GABA_ARδ in the spinal cord. Gabapentin achieved a potent protective effect on the myocardium during the course of routine clinical treatment.

Prophylactic High-Dose Gabapentin Reduces Opiate Use during Radiation Therapy for Head and Neck Squamous Cell Carcinoma

Background: The role of prophylactic high-dose gabapentin for the management of oral mucositis during radiation therapy for head and neck squamous cell carcinoma (HNSCC) remains controversial. Methods: A retrospective cohort analysis was performed on primary HNSCC patients treated at our institution. Kruskal–Wallis and Fisher’s exact tests were used to compare the patients’ baseline characteristics. Multivariate competing risk and logistic regressions were performed to evaluate time to first opioid use and feeding tube placement. Results: In total, 480 consecutive HNSCC patients were included. Within this cohort, 186 patients received 3600 mg gabapentin, 182 received 300 to 3200 mg gabapentin, and 112 received no gabapentin. The time to first opioid use was greater in the 3600 mg group compared with the no gabapentin group (34.3 vs. 23.9 days, p < 0.001) and to the 300 to 3200 mg group (28.0 days, p < 0.001). The proportion of patients requiring opioids at any point during RT was lower in the 3600 mg gabapentin group compared with the no gabapentin group (31.8% vs. 60.1%, p < 0.001) and with the 300 to 3200 mg group (63.8%, p < 0.001). Conclusions: Prophylactic use of 3600 mg gabapentin was well tolerated, halved overall opioid use, and delayed the time to first opioid use during radiation therapy.

Hepatoprotective potential of gabapentin in cecal ligation and puncture-induced sepsis; targeting oxidative stress, apoptosis, and NF-kB/MAPK signaling pathways

AIMS

Sepsis is a severe inflammatory response to infection with an incidence rate exceeding 48 million cases and 11 million sepsis-related deaths yearly. Furthermore, sepsis remains the fifth most common cause of death worldwide. The present study aimed to examine, for the first time, the potential hepatoprotective activity of gabapentin on cecal ligation and puncture (CLP)-induced sepsis in rats at the molecular level.

MAIN METHODS

CLP was used as a model of sepsis in male Wistar rats. Histological examination and liver functions were evaluated. Levels of MDA, GSH, SOD, IL-6, IL-1β, and TNF-α were investigated using ELISA. mRNA levels of Bax, Bcl-2, and NF-kB were assessed by qRT-PCR. Western blotting investigated the expression of ERK1/2, JNK1/2, and cleaved caspase 3 proteins.

KEY FINDINGS

CLP resulted in liver damage, elevated serum levels of ALT, AST, ALP, MDA, TNF-α, IL-6, and IL-1β, increased expression of ERK1/2, JNK1/2, and cleaved caspase 3 proteins, and upregulated Bax and NF-κB genes expression while it down-regulated Bcl-2 gene expression. However, gabapentin treatment significantly reduced the severity of CLP-induced biochemical, molecular, and histopathological changes. Gabapentin attenuated the levels of the proinflammatory mediators, decreased the expression of JNK1/2, ERK1/2, and cleaved caspase 3 proteins, suppressed Bax and NF-κB genes expression and increased the expression of the Bcl-2 gene.

SIGNIFICANCE

Consequently, Gabapentin reduced hepatic injury resulting from CLP-induced sepsis by reducing proinflammatory mediators, attenuating apoptosis, and inhibiting the intracellular MAPK (ERK1/2, JNK1/2)-NF-kB signaling pathway.

The Effect of Nicotine Patch on Reducing Nausea, Vomiting, and Pain Following Laparoscopic Cholecystectomy: A Randomized Clinical Trial

BACKGROUND

The effect of nicotine on nausea, vomiting, and postoperative pain has been investigated in studies on animals and humans. This study aimed to evaluate the effect of nicotine patch on decreasing nausea, vomiting, and pain in laparoscopic cholecystectomy.

METHODS

The study sample consisted of 100 non-smoking patients undergoing laparoscopic cholecystectomy under general anesthesia in a triple-blind clinical trial. One hour after the start of surgery, patients were randomly assigned to receive 17.5-mg nicotine or placebo patches. The patches located on the right arm were left for 24 hours. The visual analogue scale (VAS) for pain and N/V score for the severity of nausea and vomiting were measured at intervals of 0, 6, 12, and 24 hours.

FINDINGS

The results showed there was no statistically significant difference between the groups in terms of pain intensity as well as nausea and vomiting at different time periods after surgery (P>0.05). A total of 36 patients in the nicotine group and 24 patients in the placebo group received meperidine. There was also no statistically significant difference between the two groups in terms of analgesics (P=0.096) and antiemetics (P=0.1). Moreover, the frequency of severe nausea and vomiting during the study in the nicotine group was higher than in the placebo group (4 vs. 1) but this difference was not statistically significant (P>0.05).

CONCLUSION

Receiving a 17.5-mg nicotine patch had a similar effect to receiving placebo in controlling postoperative pain, nausea, and vomiting in non-smokers. Nicotine use had no effect on reducing analgesia.

Gabapentin use in the neonatal intensive care unit and beyond: Single center report of 104 cases

BACKGROUND

We aimed to describe our experience with gabapentin use in infants admitted to our neonatal intensive care unit (NICU), including neurodevelopmental follow-up after discharge.

METHODS

We performed a retrospective medical record review of infants prescribed gabapentin during admission to the University of Virginia NICU from 01/01/2015 to 04/30/2021. We report clinical characteristics including gabapentin indication, dosing and side-effects while in the NICU, discharge data, and assessments in outpatient developmental follow-up clinic.

RESULTS

Gabapentin was prescribed to 104 infants (median gestational age 29 weeks, median postmenstrual age at initiation 41 weeks). Sixty-one percent of infants were male. The primary indication was irritability in 86%, and 67% were receiving at least one other neurosedative medication. Median maximum dose was 25 mg/kg/day (IQR 15-35 mg/kg/day) and 84% were discharged home on gabapentin. The majority required equipment at discharge (64% gastrostomy or nasogastric tube feeds, 54% supplemental oxygen or mechanical ventilation, and 40% both). At the first neurodevelopmental follow-up appointment, at least one area of delay was identified in 93% of infants and by 2 years corrected age 66% had a diagnosis of global developmental delay.

CONCLUSIONS

NICU patients treated with gabapentin often require complex post-discharge care and require close neurodevelopmental follow up.

Evaluation and Treatment of Vulvodynia: State of the Science

Vulvodynia affects 7% of American women, yet clinicians often lack awareness of its presentation. It is underdiagnosed and often misdiagnosed as vaginitis. The etiology of vulvodynia remains unknown, making it difficult to identify or develop effective treatment methods. The purpose of this article is to (1) review the presentation and evaluation of vulvodynia, (2) review the research on vulvodynia treatments, and (3) aid the clinician in the selection of vulvodynia treatment methods. The level of evidence to support vulvodynia treatment varies from case series to randomized controlled trials (RCTs). Oral desipramine with 5% lidocaine cream, intravaginal diazepam tablets with intravaginal transcutaneous electric nerve stimulation (TENS), botulinum toxin type A 50 units, enoxaparin sodium subcutaneous injections, intravaginal TENS (as a single therapy), multimodal physical therapy, overnight 5% lidocaine ointment, and acupuncture had the highest level of evidence with at least one RCT or comparative effectiveness trial. Pre to posttest reduction in vulvar pain and/or dyspareunia in non-RCT studies included studies of gabapentin cream, amitriptyline cream, amitriptyline with baclofen cream, up to 6 weeks' oral itraconazole therapy, multimodal physical therapy, vaginal dilators, electromyography biofeedback, hypnotherapy, cognitive behavioral therapy, cold knife vestibulectomy, and laser therapy. There is a lack of rigorous RCTs with large sample sizes for the treatment of vulvodynia, rendering it difficult to determine efficacy of most treatment methods. Clinicians will be guided in the selection of best treatments for vulvodynia that have the highest level of evidence and are least invasive.

Enhanced healing efficacy of an optimized gabapentin-melittin nanoconjugate gel-loaded formulation in excised wounds of diabetic rats

The present study aimed to design and optimize, a nanoconjugate of gabapentin (GPN)-melittin (MLT) and to evaluate its healing activity in rat diabetic wounds. To explore the wound healing potency of GPN-MLT nanoconjugate, an in vivo study was carried out. Diabetic rats were subjected to excision wounds and received daily topical treatment with conventional formulations of GPN, MLT, GPN-MLT nanoconjugate and a marketed formula. The outcome of the in vivo study showed an expedited wound contraction in GPN-MLT-treated animals. This was confirmed histologically. The nanoconjugate formula exhibited antioxidant activities as evidenced by preventing malondialdehyde (MDA) accumulation and superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic exhaustion. Further, the nanoconjugate showed superior anti-inflammatory activity as it inhibited the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). This is in addition to enhancement of proliferation as indicated by increased expression of transforming growth factor-β (TGF- β), vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor receptor-β (PDGFRB). Also, nanoconjugate enhanced hydroxyproline concentration and mRNA expression of collagen type 1 alpha 1 (Col 1A1). In conclusion, a GPN-MLT nanoconjugate was optimized with respect to particle size. Analysis of pharmacokinetic attributes showed the mean particle size of optimized nanoconjugate as 156.9 nm. The nanoconjugate exhibited potent wound healing activities in diabetic rats. This, at least partly, involve enhanced antioxidant, anti-inflammatory, proliferative and pro-collagen activities. This may help to develop novel formulae that could accelerate wound healing in diabetes.

The association of gabapentin initiation and neurocognitive changes in older adults with normal cognition

Background: Gabapentin is increasingly prescribed to older adults, which raises concerns about its potential to cause neurocognitive changes. Therefore, we aimed to examine the association of gabapentin use with neurocognitive changes (i.e., cognitive decline, functional status decline, and motor function change) in older adults. Methods: We conducted a retrospective cohort study using the National Alzheimer's Coordinating Center Uniform Data Set (UDS; September 2005-March 2021 data freeze). From the eligible sample (≥age 65 years), we identified cognitively normal new-users of gabapentin and the visit they initiated gabapentin (i.e., index visit). Initiators were matched to randomly selected nonusers on year of UDS enrollment and visit number from enrollment to index. Cognitive decline was defined as any increase in the Clinical Dementia Rating global score (CDRGLOB) and as a 1-point increase in CDR sum of boxes (CDR-SB). Functional status decline was defined as a 3-point increase in the sum of the Functional Activities Questionnaire (FAQ) and as 0.3-point increase in mean FAQ. Decline in motor function was defined as new clinician reports of gait disorder, falls, and slowness. To mitigate confounding and selection bias, we used joint stabilized inverse probability of treatment weights and stabilized inverse probability of censoring weights. All analyses were conducted comparing index to index+1 and index+2 visits. Results: From the eligible UDS participants (N = 23,059), we included 480 initiators (mean age [SD]: 78.7 [6.9]; male 34.4%); 4,320 nonusers (78.3 [7.0]; 34.4%). Gabapentin initiation was significantly associated with cognitive/functional status decline: worsening CDRGLOB at index+1 visit (odds ratio [95% confidence interval]: 1.55 [1.07, 2.25]); CDR-SB at index+1 visit (1.94 [1.22, 3.09]); and mean of FAQ at index+2 visit (1.78 [1.12, 2.83]). After excluding initiators with extant motor dysfunction (n = 21), we identified 459 initiators (78.7 [6.9]; 34.0%) and 4,131 nonusers (78.2 [6.9]; 34.7%); in this sample, gabapentin initiation was associated with increased falls at the index+2 visit (2.51 [1.19, 5.31]). Conclusion: Gabapentin initiation was significantly associated with deleterious neurocognitive changes among older adults with initially normal cognition. Further studies are needed to examine the risk/benefit of prescribing gabapentin in older adults.

Evaluation of Rhodojaponin III from Rhododendron molle G. Don on oral antinociceptive activity, mechanism of action, and subacute toxicity in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

In Chinese traditional medicine, Rhododendron molle G. Don is a recognized herb to ease pain. Rhodojaponin III (RJ-III) has been identified as the main pharmacological activity and toxic component of the herb; however, oral antinociception and mechanism of RJ-III have not yet been investigated.

AIM OF THE STUDY

The significance of this study is to evaluate the effects of RJ-III on nociceptive and neuropathic pain, and to preliminarily explore the underlying mechanisms and subacute toxicity.

MATERIALS AND METHODS

The antinociception of RJ-III was evaluated by hot plate, tail-immersion, acetic acid writhing, formalin test and chronic constriction injury (CCI) model in rodents. An experimental validation was conducted using whole-cell patch clamp technique based on the most likely mechanisms of action after screening and prediction by molecular docking study. In addition, the oral subacute toxicity of RJ-III was assessed.

RESULTS

Behavioral experiments showed that RJ-III (0.20 mg/kg) reduced the latency of the nociceptive response in the hot plate and tail-immersion tests. Acetic acid and formalin-induced pain were significantly inhibited by RJ-III (0.10 and 0.05 mg/kg, respectively). Furthermore, 0.30 mg/kg of RJ-III improved hyperalgesia in the CCI-induced rats. Based on molecular docking results, electrophysiological experiments were used to demonstrate mild inhibition of voltage-gated sodium channel-related subtypes. Additionally, oral subacute toxicity that may cause leukopenia and abnormal liver function requires further attention in subsequent studies.

CONCLUSION

RJ-III mildly blocks voltage-gated sodium channel to inhibit nociceptive pain and peripheral neuralgia, but 0.375 mg/kg and above may cause side effect after long-term oral administration.

Electrospun Nanofibers for Wound Management

Electrospun nanofibers show great potential in biomedical applications. This mini review article traces the recent advances in electrospun nanofibers for wound management via various approaches. Initially, we provide a short note on the four phases of wound healing, including hemostasis, inflammation, proliferation, and remodeling. Then, we state how the nanofiber dressings can stop bleeding and reduce the pain. Following that, we discuss the delivery of therapeutics and cells using different types of nanofibers for enhancing cell migration, angiogenesis, and re-epithelialization, resulting in the promotion of wound healing. Finally, we present the conclusions and future perspectives regarding the use of electrospun nanofibers for wound management.

Proposed Canadian Consensus Guidelines on Osteoarthritis Treatment Based on OA-COAST Stages 1–4

The Canadian consensus guidelines on OA treatment were created from a diverse group of experts, with a strong clinical and/or academic background in treating OA in dogs. The document is a summary of the treatment recommendations made by the group, with treatments being divided into either a core or secondary recommendation. Each treatment or modality is then summarized in the context of available research based support and clinical experience, as the treatment of OA continues to be a multimodal and commonly a multidisciplinary as well as individualized approach. The guidelines aim to help clinicians by providing clear and clinically relevant information about treatment options based on COAST defined OA stages 1–4.

Pharmacokinetics and pharmacodynamics of repeat dosing of gabapentin in adult horses

Background

The repeated administration of high doses of gabapentin may provide better analgesia in horses than current clinical protocols.

Hypothesis and Objectives

Administration of gabapentin at 40 and 120 mg/kg PO q 12 h for 14 days will not alter serum biochemistry findings or cause adverse effects. Our objectives were to evaluate the effect of gabapentin on serum biochemistry, physical examination, and plasma pharmacokinetics of gabapentin.

Animals

Six healthy adult mares.

Methods

Horses received 40 and 120 mg/kg of gabapentin orally q 12 h for 14 days. Horses were examined and scored for ataxia and sedation daily. Serum biochemistry variables were analyzed before treatment and days 7 and 14 after gabapentin administration. Plasma disposition of gabapentin was evaluated after the first and last drug administration. Pharmacokinetic parameters were estimated using noncompartmental analysis.

Results

No changes occurred in physiologic or biochemical variables. Median (range) maximal plasma gabapentin concentrations (μg/mL) after the last dose (day 15) were 7.6 (6.2‐11) and 22 (14‐33) for 40 mg/kg and 120 mg/kg doses respectively. Maximal concentration of gabapentin was reached within 1 hour after drug administration. Repeated administration of gabapentin resulted in a median (range) area under the curve (AUC_{0‐12 hours}) last/first dose ratio of 1.5 (1.00‐2.63) and 2.92 (1.4‐3.8) for the 40 and 120 mg/kg regimens, respectively.

Conclusion and Clinical Importance

Our results suggest that horses tolerate gabapentin up to 120 mg/kg PO q 12 h for 14 days. The analgesic effect of the dosage regimens evaluated in our study warrants further research.

Gabapentinoid Use in Perioperative Care and Current Controversies

PURPOSE OF REVIEW

This review summarizes the risks and benefits of gabapentinoids (gabapentin and pregabalin) for perioperative pain control and the controversies surrounding their use in a variety of settings. We review current literature with the goal of providing patient-centric and procedure-specific recommendations for the use of these medications.

RECENT FINDINGS

Gabapentinoids are among the most prescribed medications in the USA, and typically for off-label indications such as postoperative pain. In the perioperative setting, multimodal analgesic or "opioid-sparing" regimens have become the standard of care-and some clinical protocols include gabapentinoids. At the same time, guidelines regarding the perioperative use of gabapentinoids are conflicting and evidence supporting their broad use is lacking. Gabapentinoids administered perioperatively reduce opioid requirements and pain scores for a variety of surgeries. The extent of opioid and pain reduction, however, is not always clinically significant. These medications reduce postoperative nausea and vomiting as well as pruritis, likely as a feature of reducing opioid intake, but are associated with side effects such as dizziness, ataxia, and cognitive dysfunction. Gabapentinoids also increase the risk of respiratory depression, in particular when paired with opioids. There is thus evidence suggesting that the routine use of these medications for perioperative pain management is not recommended. An individualized, patient- and surgery-specific approach should be used, although research is still needed to determine risks and benefits during perioperative use.

Is gabapentin effective and safe in the treatment of chronic pelvic pain in women: a systematic review and meta-analysis

INTRODUCTION AND HYPOTHESIS

Chronic pelvic pain (CPP) affects 2.1-24% of women, causing physical and psychological damage to women around the world. Based on the efficacy of gabapentin in the treatment of chronic pain, we conducted this study to evaluate the efficacy and safety of gabapentin in reducing pain in women with CPP.

METHODS

Systematic searches were performed in the electronic databases of PubMed, Embase, Web of Science, Scopus, Cochrane, and Clinicalkey databases. Studies focused on comparing the efficacy of gabapentin and placebo in the treatment of female CPP patients were included. RevMan 5.4 was used to analyze the results and risk of bias. Two investigators independently selected eligible studies and extracted related pain scores and side effects for meta-analysis.

RESULTS

In total, 4 RCTs were enrolled in the meta-analysis, totaling 425 patients. Among patients receiving gabapentin, the average pain scores in 3 and 6 months were significantly lower than those in the placebo group(p < 0.00001). The results showed that there was no statistical difference between gabapentin and placebo in the reduction of pain scores from baseline(p = 0.41). The incidence of side effects in the gabapentin group was significantly higher than that in the placebo group (p < 0.00001).

CONCLUSION

This systematic review and meta-analysis demonstrated that for women with CPP, gabapentin was significantly different from placebo in average pain scores at 3 and 6 months. However, the two drugs did not differ in the reduction in pain scores from baseline. Gabapentin can bring more significant side effects, whether they are common side effects or serious side effects.

The Treatment of Painful Diabetic Neuropathy

Painful diabetic peripheral neuropathy (painful-DPN) is a highly prevalent and disabling condition, affecting up to one-third of patients with diabetes. This condition can have a profound impact resulting in a poor quality of life, disruption of employment, impaired sleep, and poor mental health with an excess of depression and anxiety. The management of painful-DPN poses a great challenge. Unfortunately, currently there are no Food and Drug Administration (USA) approved disease-modifying treatments for diabetic peripheral neuropathy (DPN) as trials of putative pathogenetic treatments have failed at phase 3 clinical trial stage. Therefore, the focus of managing painful- DPN other than improving glycaemic control and cardiovascular risk factor modification is treating symptoms. The recommended treatments based on expert international consensus for painful- DPN have remained essentially unchanged for the last decade. Both the serotonin re-uptake inhibitor (SNRI) duloxetine and α2δ ligand pregabalin have the most robust evidence for treating painful-DPN. The weak opioids (e.g. tapentadol and tramadol, both of which have an SNRI effect), tricyclic antidepressants such as amitriptyline and α2δ ligand gabapentin are also widely recommended and prescribed agents. Opioids (except tramadol and tapentadol), should be prescribed with caution in view of the lack of definitive data surrounding efficacy, concerns surrounding addiction and adverse events. Recently, emerging therapies have gained local licenses, including the α2δ ligand mirogabalin (Japan) and the high dose 8% capsaicin patch (FDA and Europe). The management of refractory painful-DPN is difficult; specialist pain services may offer off-label therapies (e.g. botulinum toxin, intravenous lidocaine and spinal cord stimulation), although there is limited clinical trial evidence supporting their use. Additionally, despite combination therapy being commonly used clinically, there is little evidence supporting this practise. There is a need for further clinical trials to assess novel therapeutic agents, optimal combination therapy and existing agents to determine which are the most effective for the treatment of painful-DPN. This article reviews the evidence for the treatment of painful-DPN, including emerging treatment strategies such as novel compounds and stratification of patients according to individual characteristics (e.g. pain phenotype, neuroimaging and genotype) to improve treatment responses.

Conolidine: A Novel Plant Extract for Chronic Pain

: Pain, the most common symptom reported among patients in the primary care setting, is complex to manage. Opioids are among the most potent analgesics agents for managing pain. Since the mid-1990s, the number of opioid prescriptions for the management of chronic non-cancer pain (CNCP) has increased by more than 400%, and this increased availability has significantly contributed to opioid diversion, overdose, tolerance, dependence, and addiction. Despite the questionable effectiveness of opioids in managing CNCP and their high rates of side effects, the absence of available alternative medications and their clinical limitations and slower onset of action has led to an overreliance on opioids. Conolidine is an indole alkaloid derived from the bark of the tropical flowering shrub Tabernaemontana divaricate used in traditional Chinese, Ayurvedic, and Thai medicine. Conolidine could represent the beginning of a new era of chronic pain management. It is now being investigated for its effects on the atypical chemokine receptor (ACK3). In a rat model, it was found that a competitor molecule binding to ACKR3 resulted in inhibition of ACKR3’s inhibitory activity, causing an overall increase in opiate receptor activity. Although the identification of conolidine as a potential novel analgesic agent provides an additional avenue to address the opioid crisis and manage CNCP, further studies are necessary to understand its mechanism of action and utility and efficacy in managing CNCP.

Comparing pregabalin and gabapentin for persistent neuropathic pain: A protocol for a pilot N-of-1 trial series

Background

Evidence-based management of neuropathic pain is commonly ineffective due to the large variability in response between cases. Patients often have to trial several drugs before finding one that provides adequate relief, leading to increased costs and worsened outcomes. There is thus a need for tools to guide and streamline prescribing decisions in neuropathic pain. N-of-1 trials provide a potentially precise and economical method of selecting between multiple interventions in an individual patient, and merit a feasibility assessment for use in clinical pain practice.

Aims

We aim to evaluate the feasibility of N-of-1 trials to compare pregabalin and gabapentin for individual presentations of neuropathic pain.

Methods

This is a double-blinded multiple crossover study, with recruitment from existing patients at an outpatient pain clinic in New South Wales, Australia. Participants will undergo three 4-week treatment pairs, comprising 2 weeks of pregabalin (150–600 mg/day) and 2 weeks of gabapentin (900–3600 mg/day), in an individually randomised order. Intervention doses will be derived from participants’ existing treatment dose. Medications will be taken orally three times daily. The primary outcome will be pain intensity; measures will be self-reported daily in patient diaries. After completing all three cycles, participants and their physicians will be presented with the results of the trial to form an informed decision about their treatment.

Discussion

As a stable yet debilitating condition, neuropathic pain is especially amenable to an N-of-1 study design. A successful trial would represent a significant quality of life improvement for the patient, possibly extending over the course of their lifetime.

Neuropathic agents in the management of pruritus in burn injuries: a systematic review and meta-analysis

Objectives

Pruritus is a common and often distressing complication after a burn injury. The purpose of this review is to explore the efficacy of drugs classically used to treat neuropathic pain in the management of pruritus after burn injury.

Methods

A systematic literature search of medical databases was conducted to find studies investigating drugs listed in the National Institute for Health and Care Excellence (NICE) guideline (CG173, "neuropathic pain in adults") for the management of pruritus after burn injury in patients of any age. Controlled studies were stratified by the drug class studied and their risk of bias before conducting meta-analysis. A narrative review of case series or observational studies was presented. Severity of pruritus at any time point, with all quantitative and qualitative measures, was included.

Results

Fifteen studies were included in the final analysis, 10 investigated the use of gabapentinoids, 4 studied doxepin, and 1 local anesthetic agents. Meta-analysis of three randomized controlled trials (RCTs) demonstrated that the use of gabapentinoids was associated with an improvement in mean VAS (Visual Analog Scale) 0-10 scores of 2.96 (95% confidence interval (95% CI) 1.20 to 4.73, p<0.001) when compared with placebo or antihistamine. A meta-analysis of four RCTs investigating topical doxepin showed an improvement in mean VAS scores of 1.82 (95% CI 0.55 to 3.09, p<0.001). However, when excluding two studies found to be at high risk of bias, no such improvement was found (-0.32, 95% CI -1.64 to -0.99, p=0.83).

Conclusion

This study suggests that gabapentinoids are beneficial in the management of burn-related pruritus. There is a lack of evidence to suggest that doxepin is an effective treatment. Topical local anesthetic agents may be safe and beneficial, but studies are scarce.

Level of evidence

Systematic review, level II.

An Update on Assessment, Therapeutic Management, and Patents on Insomnia

Insomnia is an ordinary situation related to noticeable disability in function and quality of life, mental and actual sickness, and mishappenings. It represents more than 5.5 million appointments to family doctors every year. Nonetheless, the ratio of insomniacs who are treated keeps on being low, demonstrating the requirement for proceeding with advancement and dispersal of effective treatments. Accordingly, it becomes significant to provide a compelling treatment for clinical practice. It indicates a need for the determination of various critical viewpoints for the evaluation of insomnia along with various accessible alternatives for treatment. These alternatives incorporate both nonpharmacological therapy, specifically cognitive behavioural therapy for insomnia, and a number of pharmacological treatments like orexin antagonists, "z-drugs," benzodiazepines, selective histamine H1 antagonists, nonselective antihistamines, melatonin receptor agonists, antipsychotics, antidepressants, and anticonvulsants. Besides in individuals whose insomnia is due to restless leg syndrome, depression/mood disorder, or/and circadian disturbance, there is insignificant proof favouring the effectiveness of different prescriptions for the treatment of insomnia though they are widely used. Other pharmacological agents producing sedation should be prescribed with care for insomnia therapy because of greater risk of next-day sleepiness along with known adverse effects and toxicities. This review is also aimed at providing an update on various patents on dosage forms containing drugs for insomnia therapy.

A systematic review and meta-analysis of the effectiveness and adverse events of gabapentin and pregabalin for sciatica pain

Aim

This SR aims to assess the effectiveness of pregabalin and gabapentin on pain and disability caused by acute sciatica and the adverse events associated with their clinical use.

Design

Systematic review.

Databases

Electronic databases of Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Clinical Trials.gov were searched from their inception until March 1st of 2021.

Selection criteria

Randomized trials (RCT) with adults > 18 years old with acute sciatica for a minimum of 1 week and a maximum of 1 year (at least moderate pain).

Data treatment

The outcomes were pain, disability and adverse events. Data was summarized using odds ratio and mean difference. GRADE was used to calculate the level of evidence.

Results

Eight RCT involving 747 participants were included. The effect of pregabalin was assessed in 3 RCT and in one three-arm trial (pregabalin vs limaprost vs a combination of limaprost and pregabalin). Two trials assessed the effect of gabapentin compared with placebo and one compared with tramadol. One study assessed the effect of gabapentin vs pregabalin in a crossover head-to-head trial.

A statistically significant improvement on leg pain at 2 weeks and leg pain with movement at 3 and 4 months was found in a RCT comparing gabapentin with placebo. There were no statistically differences on the remaining time periods assessed for leg pain, low back pain and functional disability.

Conclusions

This SR provides clear evidence for lack of effectiveness of pregabalin and gabapentin for sciatica pain management. In view of this, its routine clinical use cannot be supported.

Gabapentinoid Pharmacology in the Context of Emerging Misuse Liability

This article will review the epidemiology and pharmacology of gabapentinoids (gabapentin and pregabalin) relevant to their emerging misuse potential and provide guidance for clinical and regulatory management. Gabapentinoids are γ-aminobutyric acid analogues that produce their therapeutic effects by inhibiting voltage-gated calcium channels and decreasing neurotransmitter release. Recently gabapentinoid prescribing and use have increased tremendously. Although traditionally thought to possess a favorable safety profile, gabapentinoid misuse has also risen significantly. Gabapentinoid misuse generally occurs in combination with other substances, most notably opioids, and may be for purposes of eliciting euphoric effects, enhancing the effects of other substances, or self-treating conditions such as withdrawal, pain, anxiety, or insomnia. Given its faster onset, increased bioavailability and potency, and nonsaturable absorption, pregabalin's pharmacokinetics theoretically enhance its misuse liability versus gabapentin. However, gabapentin can produce similar euphoric effects, and epidemiologic studies have identified higher rates of gabapentin misuse in the United States, likely because of greater availability and less regulated prescribing. Although adverse events of gabapentinoid-only ingestion are relatively benign, a growing body of evidence indicates that gabapentinoids significantly increase opioid-related morbidity and mortality when used concomitantly. In addition, significant withdrawal effects may occur on abrupt discontinuation. As a result of these trends, several US states have begun to further regulate gabapentinoid prescribing, reclassifying it as a controlled substance or mandating reporting to local prescription drug-monitoring programs. Although increased regulation of gabapentin prescribing may be warranted, harm reduction efforts and increased patient and provider education are necessary to mitigate this concerning gabapentinoid misuse trend.

Nonsurgical Approaches to Neuroma Management

Symptomatic neuromas and chronic neuropathic pain are significant problems affecting patients' quality of life and independence that are challenging to treat. These symptoms are due to structural and functional changes that occur peripherally within neuromas, as well as alterations that occur centrally within the brain and spinal cord. A multimodal approach is most effective, with goals to minimize opioid use, to capitalize on the synergistic effects of nonopioid medications and to explore potential benefits of novel adjunctive treatments.

Gabapentin in Infants: Critical Evaluation of a Novel Sedative/Analgesic Medication

Chronic pain and agitation can complicate the clinical course of critically ill infants. Randomized controlled trials of analgesia and sedation in neonatal intensive care have focused on relatively short durations of exposure. To date, clinicians have few options to treat chronic visceral pain and hyperalgesia. Gabapentin has emerged as a common therapy for a diverse group of pain syndromes and neurologic conditions in adults. In neonates, case reports and series describe the successful treatment of visceral hyperalgesia arising from gastrointestinal insults with or without concomitant neurologic morbidities. Additionally, a case report and series describe the utility of gabapentin for neonatal abstinence syndrome refractory to standard pharmacotherapy. The adverse effect profile of gabapentin, most notably bradycardia and sedation, compares favorably to alternative analgesics and sedatives. However, the long-term impacts of prolonged gabapentin therapy have not been studied. Therefore, candidates for therapy must be selected carefully, and response must be assessed objectively. Future studies must assess the short-term and long-term benefits and risks of gabapentin compared to standard therapies for chronic pain and agitation in infants and refractory neonatal abstinence syndrome.

Evaluation of discharge prescribing after rescheduling of gabapentin as a controlled substance

PURPOSE

Gabapentin has increasingly been identified as a drug of abuse, especially when used concurrently with opioids. Rescheduling gabapentin as a schedule V controlled substance may strengthen monitoring and prescribing restrictions. The purpose of this study was to characterize the impact of rescheduling gabapentin from a nonscheduled to a schedule V substance in Virginia on discharge prescribing patterns in a health system.

METHODS

This was a retrospective, pre-post, multicenter chart review conducted at 4 sites. Data from 3 months before gabapentin rescheduling (prerescheduling group) and 3 months after gabapentin rescheduling (postrescheduling group) were evaluated. The primary outcome was the percentage of newly prescribed gabapentin prescriptions upon discharge, which was compared between the pre- and postrescheduling groups.

RESULTS

A similar percentage of gabapentin prescriptions were newly prescribed in the prerescheduling group as compared to the postrescheduling group (55.0% vs 50.0%, P = 0.479). Gabapentin prescribing characteristics did not differ between the groups for new gabapentin prescriptions (n = 55 in the prerescheduling group, n = 50 in the postrescheduling group). Concomitant discharge prescribing of benzodiazepines (5.5% vs 2.0%, P = 0.619) and opioids (45.5% vs 60.0%, P = 0.136) did not differ significantly between the postrescheduling group and prerescheduling group for new gabapentin prescriptions. However, fewer opioid prescriptions exceeded 90 daily morphine milligram equivalents (MME) in the postrescheduling group as compared to the prerescheduling group for new gabapentin prescriptions (36.0% vs 20.0%, P = 0.020).

CONCLUSION

Gabapentin prescribing practices did not differ before and after rescheduling of gabapentin as a controlled substance. There was a trend toward dosages with reduced daily MME for concomitant opioid prescriptions after rescheduling. However, additional investigation with larger studies over longer periods of time is needed to discover whether gabapentin rescheduling significantly changes prescribing practices.

Extraction of Pregabalin in Urine Samples Using a Sulfonated Poly(ether ether ketone) Membrane

In this work, a simple polymer-assisted microextraction technique was developed to determine pregabalin (an anticonvulsant drug) in the urine sample. A sulfonated poly(ether ether ketone) membrane was used as a sorbent for pregabalin extraction, and the extraction performance was compared with that of the conventional polydimethylsiloxane membrane. The extraction device is free moving and tumbles continuously throughout the stirred sample solution during extraction to enhance the extraction efficiency. The electrostatic interactions between the sulfonic-acid-functionalized polymeric membrane and the amine group in the pregabalin molecule facilitate higher preconcentration factor at a shorter extraction time. Optimizing conditions of the extraction method were investigated to obtain higher extraction efficiency. The developed method exhibited good linearity in the range of 0.05 to 2 µg/mL with a correlation of determination (r²) 0.9998, acceptable limits of detection, limits of quantification, and preconcentration factor of 105-fold. The within-day and between-day precisions of pregabalin were lower than 7% relative standard deviations. Pregabalin was extracted from urine samples with recoveries of >92%, and no significant matrix effects were observed.

An investigation of the anti-inflammatory effects of gabapentin on acetic acid-induced colitis in rats

Inflammatory bowel disease (IBD) is considered a chronic inflammatory gastrointestinal disease with treatment options which exhibit low efficacies and lead to considerable side effects. Hence, the challenge to alleviate IBD complications is remained to be resolved. The purpose of this study is evaluating anti-inflammatory impacts of gabapentin on acetic acid-induced colitis in rats. Colitis was induced by the instillation of 2 mL of 3% acetic acid solution into rat's colons. Rats were randomly allocated into six groups including normal group, colitis control group, gabapentin-treated groups (25, 50, and 100 mg/kg; i.p.), and dexamethasone-treated group (1 mg/kg; i.p.). Based on the macroscopic assessment besides histological and biochemical findings [myeloperoxidase (MPO), pro-inflammatory cytokines], the efficacy of gabapentin was investigated. Gabapentin (50 and 100 mg/kg), and dexamethasone considerably reduced macroscopic and microscopic colonic lesions induced by acetic acid in rats in comparison with colitis control group. These results were confirmed by reduced levels of MPO activity and colonic concentrations of interleukin-6, interleukin-1 beta, and tumor necrosis factor-alpha, in inflamed colon tissue. Our data demonstrated that gabapentin exerts profitable impacts in experimental colitis that might be ascribed to its anti-inflammatory features and thus can be a potential therapeutic agent for IBD treatment.

Nonopioid Analgesics in Postoperative Pain Management After Cardiac Surgery

Opioid analgesia is still considered the standard of practice for cardiac surgery. In recent years, combinations of several nonnarcotic analgesics and regional analgesia have shown promise in restricting opioid use during and after cardiac surgery. Ketamine infusion, dexmedetomidine infusion, acetaminophen, ketorolac, and gabapentin are useful adjuvants in cardiac anesthesia practice and have opioid-sparing properties. The beneficial effects of nonnarcotic multimodal analgesia on intraoperative stress response, recovery profile, postoperative pain, and persistent opioid use after cardiac surgery are yet to be established, and further randomized clinical trials are required.

Post-mastectomy pain syndrome: A timely review of its predisposing factors and current approaches to treatment

Background:

Post-mastectomy pain syndrome (PMPS) has been reported to occur in 25–60% of patients following surgeries for breast cancer, the highest occurring cancer in women worldwide. There has been much research interest due to this high prevalence. However, there is still a lack of incorporation of PMPS prevention strategies in standard perioperative plans, and our understanding of this condition is still incomplete.

Objectives:

This narrative review discusses recent literature on modifiable risk factors, current approaches to prevention and treatment and potential directions for future treatment and research.

Methods:

A PubMed search with the relevant keywords was done for articles published in the last 10 years.

Results:

The incidence of PMPS can be reduced by early recognition and management of modifiable risk factors as well as the perioperative use of analgesics and regional nerve blocks. These also have a significant role in the management of established PMPS together with surgical interventions and physical therapy.

Conclusions:

PMPS is still poorly defined and hence underdiagnosed and undertreated at this point. Perioperative peripheral nerve blocks have a very promising role as preventive analgesia to reduce the risk of developing PMPS, but large-scale randomised controlled studies will need to be done to evaluate their comparative efficacy. There is a need to prioritise PMPS prevention as a standard inclusion into the perioperative plans of mastectomy patients.