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.

Gabapentin for Postoperative Pain Control and Opioid Reduction in Scrotal Surgery: A Randomized Controlled Clinical Trial.

PURPOSE: To assess the safety and efficacy of gabapentin in reducing postoperative pain among patients undergoing scrotal surgery for male infertility by conducting a randomized, double-blind, placebo-controlled trial. MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled trial, healthy men undergoing scrotal surgery with a single surgeon were randomized to receive either (1) gabapentin 600 mg given 2 hours preoperatively and 300 mg taken 3 times a day postoperatively for 3 days, or (2) inactive placebo. The primary outcome measure was difference in postoperative pain scores. Secondary outcomes included differences in opioid usage, patient satisfaction, and adverse events. RESULTS: Of 97 patients screened, 74 enrolled and underwent randomization. Of these, 4 men were lost to follow-up, and 70 were included in the final analysis (35 gabapentin, 35 placebo). Both differences in initial postoperative mean pain score (-1.14, 95% CI -2.21 to -0.08, P = .035) and final mean pain score differences (-1.27, 95% CI -2.23 to -0.32, P = .0097) indicated lower gabapentin pain compared to placebo. There were no statistically significant differences in opioid usage, patient satisfaction, or adverse events. CONCLUSIONS: These data suggest that perioperative gabapentin results in a statistically and clinically significant decrease in pain following scrotal surgery. While there was no evidence of an impact on opioid usage or patient satisfaction, given the low risk of adverse events, it may be considered as part of a multimodal pain management strategy.

Priapism associated with anti-seizure medications: a pharmacovigilance study and a review of published cases.

BACKGROUND: Recently, case reports of priapism associated with the use of some anti-seizure medications began to emerge in the literature. We aimed to investigate if there is a potential safety signal of priapism among individual anti-seizure medications and to search the literature for relevant published cases. RESEARCH DESIGN AND METHODS: We conducted a disproportionality analysis using OpenVigil 2.1 to query the United States Food and Drug Administration's Adverse Event Reporting System (FAERS) database. Literature search was conducted in PubMed/MEDLINE, Scopus and Web of Science up to 12 July 2023. RESULTS: We identified positive signal of priapism for valproic acid and its derivatives (n = 23, chi-squared = 59.943, PRR = 4.566), gabapentin (n = 20, chi-squared = 9.790, PRR = 2.060), lamotrigine (n = 16, chi-squared = 8.318, PRR = 2.120), levetiracetam (n = 16, chi-squared = 10.766, PRR = 2.329), topiramate (n = 14, chi-squared = 28.067, PRR = 3.972) and carbamazepine (n = 8, chi-squared = 6.147, PRR = 2.568), as well as published cases of priapism associated with these drugs. We also found published cases of priapism for pregabalin and phenytoin in the literature and FAERS, and at least one reported adverse event of priapism in FAERS for clonazepam, lacosamide, ethosuximide, oxcarbazepine, and vigabatrin in which they were considered primary suspect. CONCLUSIONS: Our study identified signals for priapism for several anti-seizure medications, but these results need to be confirmed in well-designed pharmacoepidemiological studies.

Gabapentinoids in Ireland 2010 to 2020: An observational study of trends in gabapentinoid prescribing, law enforcement drug seizures and postmortem toxicology.

AIMS: We explored trends in gabapentinoid prescribing, drug seizures and postmortem toxicology using a national pharmacy claims database, law enforcement drug seizures data and a population-based postmortem toxicology database. METHODS: Gabapentinoid prescribing rates per 100 000 eligible population (2010-2020), annual number of drug seizures involving gabapentinoids (2012-2020) and gabapentinoid detection (positive) rates per 100 postmortem toxicology case (2013-2020) were calculated. Negative binomial regression models were used to evaluate longitudinal trends for gabapentin and pregabalin separately. RESULTS: Gabapentin (adjusted rate ratio [RR] 1.06, 95% confidence interval [CI] 1.05-1.06, P < .001) and pregabalin (adjusted RR 1.08, 95% CI 1.08-1.09, P < .001) prescribing increased annually, with higher rates of pregabalin (vs. gabapentin) observed every year. Drug seizures involving pregabalin also increased over time (RR 1.54 95% CI 1.25-1.90, P < .0001). Of the 26 317 postmortem toxicology cases, 0.92% tested positive for gabapentin, and 6.37% for pregabalin. Detection rates increased for both gabapentin (RR 1.28, 95% CI 1.11-1.48, P < .001) and pregabalin (RR 1.13, 95% CI 1.11-1.48, P < .001) between 2013 and 2020. A total of 1901 cases (7.2%) tested positive for heroin/methadone; this sub-group had a higher detection rate for pregabalin (n = 528, 27.8%) and gabapentin (n = 41, 2.2%) over the study period, with a high burden of codetections for pregabalin with benzodiazepines (peaking at 37.3% in 2018), and pregabalin with prescription opioids (peaking at 28.9% in 2020). CONCLUSION: This study raises concerns regarding the wide availability of pregabalin in Ireland, including a growing illicit supply, and the potential for serious harm arising from poly drug use involving pregabalin among people who use heroin or methadone.

Cohort study of new off-label gabapentin prescribing in chronic opioid users.

INTRODUCTION: Gabapentin is commonly prescribed as an off-label adjunct to opioids because of its safer risk profile. Recent evidence has shown an increased risk of mortality when coprescribed with opioids. Therefore, we aimed to evaluate whether the addition of off-label gabapentin in patients with chronic opioid use is associated with a reduction in opioid dosage. METHODS: We performed a retrospective cohort study of patients with chronic opioid use with a new off-label gabapentin prescription (2010-2019). Our primary outcome of interest was a reduction in opioid dosage measured via oral morphine equivalents (OME) per day after the addition of a new off-label gabapentin prescription. RESULTS: In our cohort of 172,607 patients, a new off-label gabapentin prescription was associated with a decrease in opioid dosage in 67,016 patients (38.8%) (median OME/day reduction:13.8), with no change in opioid dosage in 24,468 patients (14.2%), and an increase in opioid dosage in 81,123 patients (47.0%) (median OME/day increase: 14.3). A history of substance/alcohol use disorders was associated with a decrease in opioid dosage after the addition of a new off-label gabapentin (aOR 1.20, 95% CI 1.16 to 1.23). A history of pain disorders was associated with a decrease in opioid dosage after the initiation of a new gabapentin prescription including arthritis (aOR 1.12, 95% CI 1.09 to 1.15), back pain (aOR 1.10, 95% CI 1.07 to 1.12), and other pain conditions (aOR 1.08, 95% CI 1.06 to 1.10). CONCLUSIONS: In this study of patients with chronic opioid use, an off-label gabapentin prescription did not reduce opioid dosage in the majority of patients. The coprescribing of these medications should be critically evaluated to ensure optimal patient safety.

The Safe Use of Analgesics in Patients with Cirrhosis: A Narrative Review.

Pain is prevalent in patients with cirrhosis. Due to potential alterations in drug metabolism, risk for adverse effects, and complications from cirrhosis, physicians are often faced with difficult choices when choosing appropriate analgesics in these patients. Overall, acetaminophen remains the preferred analgesic. Despite its potential for intrinsic liver toxicity, acetaminophen is safe when used at 2 g/d. In contrast, non-selective nonsteroidals should be avoided due to their multiple side effects, including worsening renal function, blunting diuretic response, and increasing risk of portal hypertensive and peptic ulcer bleeding. Celecoxib can be administered for short term (≤5 days) in patients with Child's A and Child's B cirrhosis (50% dose reduction). Opioids carry the risk of precipitating hepatic encephalopathy and should generally be avoided, when possible. If clinical situation demands their use, opioid use should be limited to short-acting agents for short duration. Gabapentin and pregabalin are generally safe. Duloxetine should be avoided in hepatic impairment. Topical diclofenac and lidocaine seem to be safe in patients with cirrhosis.

Harms were detected but not reported in six clinical trials of gabapentin.

OBJECTIVES: We sought to assess and report harms that were observed but not disclosed previously in clinical trials of gabapentin. STUDY DESIGN AND SETTING: We reanalyzed individual participant data from six randomized parallel trials of gabapentin for neuropathic pain, and we conducted meta-analyses. Between 1996 and 2003, adult participants were assigned to gabapentin (600 mg-3,600 mg per day) or placebo for 7-14 weeks. We calculated the proportion of participants with: one or more adverse events (AEs), one or more serious AEs, discontinued, discontinued because AEs. We also estimated effects on AEs at three levels of aggregation using COSTART, a hierarchical system for classifying AEs: body system, midlevel system, preferred term. RESULTS: We found evidence of important harms that were neither included in published trial reports nor included in systematic reviews. Aggregating related harms led to greater confidence that gabapentin might harm the nervous system and possibly the digestive, metabolic and nutritional, respiratory, sensory, and urogenital body systems. Nervous system harms were more common than previous reports suggest. CONCLUSION: Clinical trials identified harms that were not reported publicly, and journal articles overstated uncertainty about harms. Relying on journal articles to evaluate gabapentin's harms could contribute to incomplete and misleading conclusions in systematic reviews and guidelines. To prevent bias arising from the selective nonreporting of results, journal articles should describe how to access data for all harms observed in clinical trials (e.g., by sharing individual participant data).

Gabapentin monotherapy for epilepsy: A review.

BACKGROUND: Epilepsy is one of the most common chronic neurological disorders, affecting more than 50 million people globally. In this review we summarised the evidence from randomised controlled trials of gabapentin used as monotherapy for the treatment of focal epilepsy, both newly diagnosed and drug-resistant, with or without secondary generalisation. OBJECTIVE: To assess the effects of gabapentin monotherapy for people with epileptic focal seizures with and without secondary generalisation. METHODS: We searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 24 February 2020) on 25 February 2020. CRS Web includes randomised or quasi-randomised controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, the Cochrane Central Register of Controlled Trials (CENTRA), and the specialised registers of Cochrane Review Groups including the Cochrane Epilepsy Group. We also searched several Russian databases, reference lists of relevant studies, ongoing trials registers, conference proceedings, and we contacted trial authors. RESULTS: We found five randomised controlled trials (3167 participants) comparing gabapentin to other antiepileptic drugs (AEDs) and differing doses of gabapentin as monotherapy for newly diagnosed focal epilepsy and drug- resistant focal epilepsy with or without secondary generalisation. Two review authors independently applied the inclusion criteria, assessed trial quality, risk of bias, and extracted data. We used the GRADE approach to assess the certainty of evidence and present seven patient-important outcomes in the "Summary of findings" tables. The quality of evidence was very low to moderate due to poor reporting quality, poor trial design, and other risks of bias, such as selective presentation of findings and potential heavy industry input. Better quality research may change our certainty in the effect estimates. None of the included trials reported on the number of people with 50% or greater reduction in seizures and time to withdrawal (retention time) in an extractable way. Gabapentin-treated participants were more likely to withdraw from treatment for any cause (285/539) than those treated with lamotrigine, oxcarbazepine, or topiramate pooled together (695/1317) (RR 1.13, 95% CI 1.02 to 1.25; 3 studies, 1856 participants; moderate-certainty evidence), but not carbamazepine. Fewer people treated with gabapentin withdrew from treatment owing to adverse events (190/525) than those treated with carbamazepine, oxcarbazepine, or topiramate (479/1238), (RR 0.79, 95% CI 0.69 to 0.91; 1763 participants, 3 studies; moderate-certainty evidence), but not lamotrigine. CONCLUSION: Gabapentin as monotherapy probably controlled seizures no better and no worse than comparator AEDs (lamotrigine, carbamazepine, oxcarbazepine, and topiramate). Compared to carbamazepine, gabapentin was probably better in retaining people in studies and preventing withdrawals due to adverse events. The most common side effects associated with gabapentin were ataxia (poor co-ordination and unsteady gait), dizziness, fatigue, and drowsiness.

Atrial fibrillation induced by gabapentin: a case report.

BACKGROUND: Gabapentin is commonly prescribed for the treatment of neuropathic pain, restless leg syndrome, and partial-onset seizures. Although the most frequent side effects of gabapentin are associated with the central nervous system, gabapentin can also affect the cardiovascular system. Case reports and observational studies have showed that gabapentin can be associated with increased risk of atrial fibrillation. However, all the evidence is concentrated in patients older than 65 years old with comorbidities that predispose them to the development of arrhythmias. CASE PRESENTATION: We describe a case of an African American male in his 20s that presented to our chronic pain clinic with lumbar radiculitis and developed atrial fibrillation 4 days after being started on gabapentin. Laboratory workup did not show significant abnormalities, including normal complete blood count, comprehensive metabolic panel, toxicology screen, and thyroid-stimulating hormone. Transthoracic and transesophageal echocardiography showed a patent foramen ovale with right-to-left shunt. The patient was initially treated with diltiazem for heart rate control and apixaban. Direct current cardioversion with successful conversion to sinus rhythm was performed 24 hours after admission. The patient was then discharged on apixaban and diltiazem. Apixaban was changed to low-dose aspirin 1 month after discharge. CONCLUSION: With rapidly increasing usage of gabapentin for approved and off-label indications, it is important to identify unintended adverse effects of this drug as they are considered safe alternatives to opioids. New-onset atrial fibrillation could be induced by gabapentin in young individuals.

Deprescribing interventions for gabapentinoids in adults: A scoping review.

The emerging issue of rising gabapentinoid misuse is being recognized alongside the lack of current evidence supporting the safe and effective deprescribing of gabapentinoids. This scoping review aimed to assess the extent and nature of gabapentinoid deprescribing interventions in adults, either in reducing dosages, or prescribing of, gabapentinoids. Electronic databases were searched on 23 February 2022 without restrictions. Eligible studies included randomized, non-randomized and observational studies that assessed an intervention aimed at reducing/ceasing the prescription/use of a gabapentinoid in adults for any indication in a clinical setting. The research outcomes investigated the type of intervention, prescribing rates, cessations, patient outcomes and adverse events. Extracted outcome data were categorized as either short (≤3 months), intermediate (>3 but <12 months) or long (≥12 months) term. A narrative synthesis was conducted. The four included studies were conducted in primary and acute care settings. Interventions were of dose-reducing protocols, education and/or pharmacological-based approaches. In the randomized trials, gabapentinoid use could be ceased in at least one third of participants. In the two observational trials, gabapentinoid prescribing rates decreased by 9%. Serious adverse events and adverse events specifically related to gabapentinoids were reported in one trial. No study included patient-focused psychological interventions in the deprescribing process, nor provided any long-term follow-up. This review highlights the lack of existing evidence in this area. Due to limited available data, our review was unable to make any firm judgements on the most effective gabapentinoid deprescribing interventions in adults, highlighting the need for more research in this area.

Antitussive efficacy of the current treatment protocol for refractory chronic cough: our real-world experience in a retrospective cohort study.

BACKGROUND: The management of refractory chronic cough (RCC) is a great challenge. Neuromodulators have long been used for RCC with imperfect efficacy. OBJECTIVES: We summarized the outcomes of the current treatments used at our specialist cough clinic, which provides a guideline-led service and real-world experience for the future management of RCC. DESIGN: This is a single-centre retrospective observational cohort study. METHODS: Consecutive RCC patients (the first clinic visit between January 2016 and May 2021) were included into this observational cohort study. Medical records in the Chronic Cough Clinical Research Database were fully reviewed using uniform criteria. The included subjects were followed-up for at least 6 months after the final clinic visit via instant messages with the link to self-scaled cough-associated questionnaires. RESULTS: Overall, 369 RCC patients were analysed with a median age of 46.6 years and a cough duration of 24.0 months. A total of 10 different treatments were offered. However, 96.2% of patients had been prescribed at least one neuromodulator. One-third of patients had alternative treatments prescribed given the poor response to the initial therapy and 71.3% favourably responded to at least one of the treatments. Gabapentin, deanxit, and baclofen had comparable therapeutic efficacy (56.0%, 56.0%, and 62.5% respectively; p = 0.88) and overall incidences of adverse effects (28.3%, 22.0%, and 32.3% respectively; p = 0.76). However, 19.1 (7.7-41.8) months after the last clinic visit, 65.0% reported improvement (24.9%) or control of their cough (40.1%); 3.8% reported a spontaneous remission and 31.2% still had a severe cough. Both HARQ (n = 97; p < 0.001) and LCQ (n = 58; p < 0.001) demonstrated marked improvement. CONCLUSION: Trying different neuromodulators is a pragmatic strategy for RCC, which helped around two-thirds of patients. Relapse is common on withdrawal or reduction of dosage. Novel medication for RCC is an urgent clinical need. PLAIN LANGUAGE SUMMARY: This is the first report that fully represented a guideline-led treatment protocol for refractory chronic cough (RCC) based on a large series of patients, which evaluated the short- and long-term effects of the currently available treatments for RCC. We found that the therapeutic trial of different neuromodulators is a pragmatic strategy, which helped around two-thirds of patients. Gabapentin, deanxit (flupentixol/melitracen), and baclofen had similar therapeutic outcomes. This study may offer real-world experience for the future management of RCC.

The effect of gabapentin and pregabalin administration on memory in clinical and preclinical studies: a meta-analysis and systematic review.

BACKGROUND: Today, gabapentinoids such as Gabapentin (GBP) and pregabalin (PGB) are widely used as painkillers. This may alter the function of the nervous system; hence their results may include a difference in memory and processes that end in memory formation. This study aims to conclude whether gabapentinoids can alter memory or not by reviewing and analyzing clinical and preclinical studies. MATERIAL AND METHODS: A comprehensive search was carried out in databases including PUBMED, EMBASE, SCOPUS, and Web of Science. In the included studies, memory was measured as an outcome variable in clinical or preclinical studies. RESULT: A total of 21 articles (4 clinical, 17 preclinical) were included in the meta-analysis by STATA Software. The results showed that memory changes under the influence of GBP. Both the administrated dosage and the time of administration are important in the final results and latency time of retention. GBP administration in healthy animals increased latency time, whereas if the administration of GBP took place exactly before training, the latency time increased slightly. Short-term administration of PGB in healthy volunteers is accompanied by transient side effects on the CNS. However, the number and homogeneity of the studies were not such that a meta-analysis could be performed on them. CONCLUSION: Clinical and preclinical studies showed that PGB administration did not confirm its improving memory effect. GBP administration in healthy animals increased latency time and improved memory. Although it depended on the time of administration.

Non-opioid antinociceptive drugs : risk of respiratory depression and death related to concomitant use of gabapentinoids in addition to opioids.

INTRODUCTION: Respiratory depression and opioid-related death are reported when opioids are associated with gabapentinoids. Meta-analyses of randomized clinical trials investigating efficacy and safety of such association failed to assess these risks because of the lack of data. The aim of this systematic review was to investigate the risk of respiratory depression or death during this combination in the scientific literature, including case reports or series, observational studies, and clinical trials. AREAS COVERED: PubMed®, Web of Science®, Embase®, and Google Scholar® were searched from their inception to December 2021, for original articles in English, French, and German. Data synthesis was done on a narrative approach by type of articles. EXPERT OPINION: The review included 25 articles (4 case reports, 2 cross-sectional, 3 case-control, 14 cohort studies, and 2 clinical trials). Respiratory depression or opioid-related death and co-exposure to gabapentinoids were associated in perioperative setting/chronic pain (odds ratios around 1.3) and in opioid maintenance treatment (hazard ratio 3.4). These findings are in agreement with experimental studies showing that a single dose of gabapentinoid may reverse opioid respiratory tolerance. Because the combination gabapentinoids-opioids is highly prevalent in all clinical context, all health care professionals and patients must be aware of this risk.

The safety and efficacy of gabapentinoids in the management of neuropathic pain: a systematic review with meta-analysis of randomised controlled trials.

BACKGROUND: There are increasing concerns regarding the abusive potential of gabapentinoids putting at risk patients with neuropathic pain requiring long-term pain management. The evidence to support this is rather inconcusive. AIM: This systematic review aimed to evaluate the safety and efficacy of gabapentinoids in the management of neuropathic pain with a focus on randomised controlled trials (RCTs) and categorising the side effects according to the body systems they were affecting. METHOD: Searches were conducted in MEDLINE (PubMed), EMBASE, Web of Science, PsycoINFO, and CINAHL (EBSCO), and included RCTs to identify and critically appraise studies investigating safety and therapeutic effects of gabapentionoids in adults with neuropathic pain. Data extraction was conducted using an established Cochrane form and the risk-of-bias tool was used in the assessment of quality. RESULTS: 50 studies (12,398 participants) were included. The majority of adverse events pertained to the nervous system (7 effects) or psychiatric (3 effects) disorders. There were more adverse effects reported with pregabalin (36 effects) than with gabapentin (22 effects). Six pregabalin studies reported euphoria as a side effect, while no studies reported euphoria with gabapentin. This was the only side effect that may correlate with addictive potential. Gabapentioids were reported to significantly reduce pain compared to placebo. CONCLUSION: Despite RCTs documenting the adverse events of gabapentionoids on the nervous system, there was no evidence of gabapentinoid use leading to addiction, suggesting an urgent need to design studies investigating their abusive potential.

Randomized double-blind, placebo-controlled study of oral gabapentin for prevention of neuropathy in patients receiving paclitaxel.

BACKGROUND: Peripheral neuropathy is a common dose-limiting side effect of paclitaxel. To date, there is no effective strategy to prevent paclitaxel-induced peripheral neuropathy. A recent small phase II study demonstrated the potential role of oral gabapentin in this setting. This phase III study is aimed to assess the efficacy of oral gabapentin in preventing paclitaxel-induced neuropathy. OBJECTIVE: To compare the efficacy of oral gabapentin with placebo in preventing clinically significant peripheral neuropathy (NCI CTCAEv5.0 grade 2 or higher) in patients receiving paclitaxel. METHODS: This is a randomized, placebo-controlled, double-blind, parallel-group superiority trial. The primary outcome is the development of grade 2 or higher chemotherapy-induced peripheral neuropathy. Secondary outcomes include any grade neuropathy, the percentage change in sensory nerve conduction velocities in peripheral nerves, time to development of any grade neuropathy, paclitaxel dose reductions and delays due to peripheral neuropathy, patient-reported outcomes, adverse events, and adherence to oral therapy. A total of 136 patients receiving paclitaxel will be randomly allocated (stratified by weekly vs. non-weekly administration) to receive either oral gabapentin or placebo till three weeks after the last dose of chemotherapy or occurrence of the primary outcome. CONCLUSION: This study aims to find if oral gabapentin reduces the incidence of grade 2 or higher chemotherapy-induced peripheral neuropathy in patients receiving paclitaxel. TRIAL REGISTRATION: The trial is registered prospectively with the Clinical Trials Registry of India (CTRI/2022/02/040030) on April 4, 2022.

Risk of parkinsonism and related movement disorders with gabapentinoids or tramadol: A case-crossover study.

INTRODUCTION: A safety signal concerning parkinsonism and related movement disorders with gabapentinoids (gabapentin and pregabalin) or tramadol was detected by reviewing individual case reports and data mining in spontaneous report databases. Well-designed pharmacoepidemiological studies are needed to assess the signal. OBJECTIVE: This study aimed to investigate the association of exposure to gabapentinoids or tramadol with the risk of parkinsonism and related movement disorders. METHODS: We conducted a case-crossover study using a Japanese electronic medical records database. Patients with newly diagnosed parkinsonism or related movement disorders between January 1, 2007, and April 14, 2019, were identified. The diagnosis date of outcomes was defined as the index date. We assessed the exposure of each patient to gabapentinoids or tramadol during a 90-day hazard period ending 1 day before the index date and in three 90-day reference periods. Multivariable conditional logistic regression models were employed to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). To confirm the robustness of the primary findings, we also performed sensitivity analyses using a case-case-time-control design, a different time window for hazard and reference periods, a different definition of outcome, and different number of reference periods. RESULTS: A total of 28,972 eligible cases were included in the primary analysis. Exposure to gabapentinoids (aOR, 2.12; 95% CI, 1.73-2.61) and tramadol (aOR, 2.04; 95% CI, 1.57-2.64) was associated with increased risk. Results were consistent across sensitivity analyses. CONCLUSION: Our findings serve as a caution to physicians who prescribe gabapentinoids or tramadol in routine clinical practice.

Pharmacist, prescriber, and drug policy expert opinions on gabapentinoid misuse.

BACKGROUND: Gabapentinoids (gabapentin and pregabalin) are widely used in clinical practice, but recent evidence indicates that they carry an increased risk of misuse. As healthcare professionals (HCPs) and policymakers plan different strategies to promote harm reduction, it is important to understand different interested party viewpoints. OBJECTIVE: To explore prescriber, pharmacist, and drug policy expert (DPE) awareness, opinions, and experiences regarding gabapentinoid misuse. METHODS: A qualitative description study using individual semi-structured virtual interviews was conducted between February and April 2021. Participants included prescribers (physicians, physician assistants [PA], or nurse practitioners [NP]) and pharmacists practicing in outpatient, ambulatory, or community-based healthcare settings; individuals with relevant drug policy expertise were also included. Qualtrics (Provo, Utah) and Zoom (San Jose, California) were used to facilitate quantitative (for initial screening and participant characteristics) and qualitative (interview) data collection. Data were coded and organized into themes in NVivo (QSR International; Burlington, Massachusetts) using thematic analysis steps. RESULTS: A total of 43 individuals participated in this study, including 16 (37.2%) pharmacists, 13 (30.2%) physicians, seven (16.3%) NPs, four (9.3%) DPEs, two (4.7%) pharmacist/DPEs, and one (2.3%) PA. Results were organized along four themes: (1) challenges/opportunities in gabapentinoid use; (2) gabapentinoid misuse awareness; (3) solutions to gabapentinoid misuse and (4) contributing barriers in pain management. Participants invoked different opinions in their consideration of gabapentinoid misuse, including the desire for harm reduction, the limitations of the current healthcare and insurance system, the lack of options for pain and substance use disorder treatment, and the influence of patient expectations. CONCLUSIONS: Gabapentinoid misuse was commonly framed in comparative fashion to ongoing concerns with opioids, and proposed solutions often focused less on regulatory control and more toward patient and HCP education and an overhaul of the health system approach to substance use and healthcare overall.

The risk of fragility fractures following initiation of gabapentin and pregabalin-A Danish, nationwide, high-dimensional propensity score-matched cohort study.

Gabapentin and pregabalin have been associated with an increased risk of fragility fractures. Due to differences in pharmacokinetics, we aimed to assess the fracture-risk difference between the two medicines. We performed a Danish nationwide new user, high-dimensional propensity score-matched cohort study to assess the 90-day risk of fragility fractures among adults, from January 1996 to December 2018. We applied a high-dimensional propensity score to match new users of gabapentin with new users of pregabalin in a 1:1 intention-to-treat approach. Hazard ratios (HRs), incidence rates (IRs) and incidence rate difference (IRD) were obtained. We identified 388 236 eligible patients of which 294 223 and 98 869 initiated gabapentin and pregabalin, respectively. We included 48 272 matched pairs for further analysis. The mean age was 56 (IQR 44-69) years, and the average follow-up was approximately 11 500 person-years (PY). The IRs of fragility fractures were 23.7 (95%CI 21.0-26.7) and 23.2 (95%CI 20.5-26.2) per 1000 PY for gabapentin and pregabalin-exposed patients, respectively. This yielded an HR of 1.02 (95%CI 0.86-1.21) when using gabapentin as the intervention drug and pregabalin as the reference drug. The IRD was estimated to 0.5 PY (95%CI -3.5-4.5). In conclusion, short-term risk of fragility fractures among gabapentin initiators was not different compared to those initiating pregabalin.

Gabapentin-Induced Overflow Urinary Incontinence: A Case Report and Review of the Literature.

Gabapentin (GBP) is a structural analog of gamma-aminobutyric acid (GABA) that is commonly used in palliative care for symptom management indications including neuropathic pain syndromes, hiccups, cough, and anxiety. An uncommon adverse effect of GBP is urinary incontinence (UI). We report the case of a 61-year-old male with metastatic non-small cell lung cancer who developed probable overflow UI while receiving 1200 mg/day of GBP for chemotherapy-induced peripheral neuropathy. The patient self-tapered GBP to 600 mg/day which resolved the overflow UI, but resulted in poorly controlled bilateral foot pain. The palliative care physician rotated the patient to pregabalin 150 mg/day and his bilateral foot pain improved after his regimen was titrated to 200 mg/day. The patient did not experience overflow UI while taking pregabalin despite the similar pharmacology and comparable doses to GBP. We believe this is the first case report to describe subsequent achievement of pain control by substituting pregabalin without recurrence of UI. Healthcare professionals should consider GBP as a potential cause when evaluating patients presenting with new onset overflow UI.

Efficacy and Safety of Gabapentin on Postoperative Pain Management After Bariatric Surgery: A Systematic Review and Meta-Analysis.

PURPOSE: Examine the efficacy and safety of perioperative gabapentin in bariatric surgical patients. DESIGN: Systematic Review and Meta-analysis. METHODS: An exhaustive search was conducted using PubMed, Cochrane Library, MEDLINE, CINAHL, Google Scholar, and other gray literature. Only randomized controlled trials evaluating the use of gabapentin in bariatric surgery were included. Risk ratio (RR) and mean difference (MD) were used to estimate outcomes with suitable effect models. Quality of evidence was assessed using the Risk of Bias and GRADE system. FINDINGS: Four trials consisting of 283 patients were analyzed. The use of gabapentin significantly lowered the cumulative pain score in the first 24 hours after surgery by an average of 1.04 (MD, -1.04; 95% CI, -1.45 to -0.63; P < .00001). Gabapentin also reduced the overall morphine equivalent consumption by 7.89 mg (MD, -7.89; 95% CI, -13.56 to -2.2; P = .006). However, gabapentin did not affect the incidence of PONV (RR, 0.61; 95% CI, 0.38-1.00; P = .05), somnolence (RR, 1.25; 95% CI, 0.57-2.73; P = .57), dizziness (RR, 1.01; 95% CI, 0.40-2.54; P = .99), and headache (RR, 0.76; 95% CI, 0.25-2.30; P = .62). Substantial heterogeneity, imprecision of the effect size, and potential publication bias were limitations of this review. CONCLUSIONS: The use of gabapentin is effective in the management of postoperative pain in bariatric surgery. However, there is limited data regarding the opioid-sparing effect and adverse effect profiles of gabapentin in the bariatric surgical population.