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.

Patterns of gabapentinoid use among long-term opioid users.

OBJECTIVE: Understanding the clinical and demographic profile of patients on gabapentinoids can highlight areas of prescribing disparities, inform clinical practice, and guide future research to optimize effectiveness and safety of gabapentinoids for pain management. We used a national sample of Medicare beneficiaries to examine trends, patterns, and patient-level predictors of gabapentinoid use among long-term opioid users. METHODS: Using a national Medicare sample between 2014 and 2020, we examined factors associated with gabapentinoid use among long-term opioid users. We included Medicare eligible long-term opioid users with no prior gabapentinoid use. The primary outcome was gabapentinoid use after the long-term opioid use episode. Logistic regression was used to test the association with gabapentinoid use for year, age, sex, race/ethnicity, region, Medicare entitlement, low-income status, frailty, pain locations, anxiety, depression, opioid use disorder, and opioid morphine milligrams equivalent. RESULTS: Gabapentinoid use among long-term opioid users increased from 12.6% in 2014 to 16.8% in 2019 (p < .0001). Factors associated with increased gabapentinoid use were Hispanic ethnicity, back pain, nerve pain, and moderate or high opioid usage. Factors associated with decreased gabapentinoid use were older age and Medicare entitlement due to old age. CONCLUSIONS: Variation of gabapentinoid use by socio-demographics and insurance status indicates opportunities to improve pain management and a need for shared therapeutic decision making informed by discussion between pain patients and providers regarding safety and effectiveness of pain therapies. Our findings underscore the need for future research into the comparative effectiveness and safety of gabapentinoids for non-cancer chronic pain in various subpopulations.

Risk of Suicidal Ideation and Behavior Following Early-Onset Idiopathic Restless Legs Syndrome Treatment.

PURPOSE: To estimate incidence rates of suicidal ideation and behavior following treatment initiation with gabapentinoids or dopamine agonists (DAs) in patients with newly diagnosed early-onset idiopathic restless legs syndrome (RLS) and to examine suicidal behavior risk, comparing between those receiving gabapentinoids and DAs. METHODS: A new user retrospective cohort study using MarketScan claims data from 2012 to 2019 was conducted. Exposures were monotherapy gabapentinoids or DAs initiated within 60 days of new RLS diagnosis. Three varying outcome measures of suicidality were examined and incidence rates were calculated for each. A log-binomial regression model the estimated relative risk (RR) of the outcomes with gabapentinoids. Propensity score weighting adjusted for baseline covariates, including age, substance use disorders, hyperlipidemia, antipsychotic use, hypnotic/sedative use, and mood stabilizer use, which were most imbalanced before weighting. RESULTS: The cohort included 6672 patients, with 4986 (74.7%) initiating a DA and 1686 (25.3%) initiating a gabapentinoid. Incidence rates for all outcome measures were higher in the gabapentinoid group (suicidality: 21.6 vs. 10.7 per 1000 person-years; suicidality with self-harm: 23.0 vs. 11.1 per 1000 person-years; overdose- and suicide-related events: 30.0 vs. 15.5 person-years). Associated risk of suicidality (adjusted RR, 1.27 [95% CI, 0.86-1.88]); suicidality with self-harm (adjusted RR, 1.30 [95% CI, 0.89-1.90]); or overdose- and suicide-related events (adjusted RR, 1.30 [95% CI, 0.93-1.80]) was not significant with gabapentinoids. CONCLUSIONS: Incidence rates for suicidal ideation and behavior were higher among the gabapentinoid group, although increased risk was not detected after adjustment. A possible signal cannot be ruled out given limitations of the data and rarity of the outcome.

Gabapentin-induced Multifocal Myoclonus.

BACKGROUND: Gabapentin is the most commonly preferred agent for neuropathic pain in general practice as it is usually well tolerated, but occasionally, its toxicity may occur at standard doses, especially in elderly individuals, even without any prior comorbidities. CASE: We present an elderly male with normal renal parameters, who was started on gabapentin for neuropathic pain. He developed multifocal myoclonus all over the body within few days after starting gabapentin and subsided completed after withdrawal of the drug. CONCLUSION: Acute hyperkinetic movement disorders such as multifocal or segmental myoclonus in elderly patients warrant a prompt review of recent drug history, especially gabapentin, even in the background of normal renal function.

Alcohol-related posterior reversible encephalopathy syndrome: a case report of a patient managed with a benzodiazepine-sparing regimen for alcohol withdrawal.

We report a case of posterior reversible encephalopathy syndrome (PRES) during treatment for alcohol withdrawal syndrome with gabapentin and clonidine. The patient developed severe hypertension, confusion and tremor, culminating in bilateral vision loss and a seizure. Imaging revealed posterior cerebral edema. Treatment with benzodiazepines, antihypertensives, and anti-seizure medications led to resolution. One year later, imaging showed resolution of the findings. We review the associated literature and propose the recognition of a PRES sub-entity, Alcohol-Related PRES (ARPRES), which can appear in the setting of alcohol withdrawal syndrome, chronic alcohol use, and acute alcohol intoxication, with or without hypertension.

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.

Usefulness of Gabapentin as an Alternative/Adjunct Therapy for Delirium: A Retrospective Observational Study.

BACKGROUND: Antipsychotics are commonly used to treat delirium but can adversely affect the extrapyramidal and cardiac conduction systems. Antipsychotic use has also been reported to be associated with increased mortality in older adults. Therefore, alternative and adjunct medications for delirium are necessary. We retrospectively assessed the efficacy and safety of gabapentin (GBP) as an alternative and adjunct medication for delirium. METHODS: We retrospectively investigated the records of patients with delirium treated with GBP (71 patients; median age, 81 years; interquartile range, 76-87.5 years; 54.9% males) at a general hospital. We examined duration to delirium improvement, as assessed by the Intensive Care Delirium Screening Checklist (ICDSC) and DSM-5 criteria, as well as adverse events. RESULTS: The median (interquartile range) GBP dose was 200 mg (150-350 mg) /day. A total of 71.8% and 85.9% of the patients failed to meet the diagnostic criteria for delirium at 2 days and 5 days after initial administration, respectively (p<0.05). In subgroup analysis, patients with a history of epilepsy or cerebrovascular disease responded better to GBP than did those without such histories, suggesting that patients with abnormal/borderline neuronal activity respond to GBP even though they do not exhibit seizures. GBP did not induce extrapyramidal symptoms, cardiac conduction disturbances, hyperglycemia, or epilepsy but caused sleepiness and myoclonus. CONCLUSIONS: GBP may improve delirium with fewer adverse effects and may be a safe alternative or adjunct treatment for delirium. Dosage adjustment may be necessary to prevent sleepiness.

Association between gabapentin use and risk of dementia in adults with chronic pain: A nested case-control study.

STUDY OBJECTIVE: To explore the association between gabapentin use and the risk of dementia in patients with chronic pain, considering the rising concerns of dementia in an aging population and the potential cognitive impacts of chronic pain management. DESIGN: A nested case-control study utilizing data from a longitudinal health insurance database. SETTING: The study is based on a longitudinal health insurance database spanning 2000-2019 in Taiwan. PATIENTS: A total of 201,492 patients aged 50 years and older diagnosed with chronic pain between 2001 and 2017 were included. The study focused on individuals with chronic pain, excluding those diagnosed with dementia a year before or after their chronic pain diagnosis. INTERVENTION: Analysis of gabapentin prescription history was conducted, considering the cumulative dose from the chronic pain diagnosis date to the dementia diagnosis date or equivalent period for controls. MEASUREMENT: Data included demographics, gabapentin prescription history, and comorbidities. Logistic regression was used to estimate odds ratios for dementia risk. MAIN RESULTS: No significant difference in the risk of dementia was found between low and high cumulative doses of gabapentin. The adjusted odds ratio for dementia risk associated with gabapentin use was 0.91 (95 % C.I. 0.83-1.01), indicating no substantial increase in risk. CONCLUSION: Long-term Gabapentin therapy for chronic pain is not associated with a differential risk of dementia across dosage levels, irrespective of age or gender. Further study into its potential cognitive impacts is essential.

Efficacy and Safety of Gabapentinoids for Acute Herpes Zoster Neuralgia: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

OBJECTIVE: This study aimed to systematically evaluate the clinical efficacy of gabapentin and pregabalin in the treatment of acute herpes zoster (HZ) neuralgia, including pain control and the occurrence of adverse effects. METHODS: A systematic computerized search was conducted in October 2023 in PubMed, Embase, Web of Science, Cochrane Library, VIP, CNKI, and Wanfang databases. Data from randomized controlled trials (RCTs) comparing gabapentin analogs for the treatment of acute HZ neuralgia were searched. Endpoints were visual analog scores (Visual Analog Scale) and adverse effects at 1, 2, and 4 weeks. Data from studies that met the inclusion criteria were extracted for meta-analysis and sensitivity analysis using Revman 5.4 and Stata16. RESULTS: The study included 292 patients from 6 RCTs. Of these, 118 were in the gabapentin-treated group, 37 were in the pregabalin-treated group, and 137 were in the placebo-controlled group. The gabapentin group showed superior pain reduction compared with the placebo group ( P < 0.05), but adverse events were more frequent. CONCLUSION: Gabapentin can effectively reduce acute HZ neuralgia in patients. Pregabalin requires additional RCTs to supplement the analysis.

Gabapentinoids for chemotherapy-induced peripheral neuropathy: systematic review and meta-analysis.

INTRODUCTION: Chemotherapy-induced peripheral neuropathy (CIPN) affects patients' quality of life and treatment effectiveness. Gabapentinoids, like gabapentin and pregabalin, are often used for CIPN treatment, but their efficacy and safety remain uncertain. This study reviews and analyses randomised controlled trial data on this topic. MATERIALS/METHODS: We searched PubMed, Embase and Cochrane CENTRAL until 29 August 2022 for studies on gabapentinoid use in CIPN. Meta-analysis was performed using RevMan V.5.4 and the Metafor package in R. Outcomes included pain scores, quality of life and adverse drug events. RESULTS: For the prevention setting, our meta-analysis shows that pregabalin did not significantly improve average pain (standardised mean difference (SMD) -0.14, 95% CI -0.51 to 0.23; I2=26% (95% CI 0% to >98%)) or quality of life (mean difference (MD) 2.5, 95% CI -4.67 to 9.67; p=0.49) in preventing CIPN compared with placebo. However, it showed a potential trend towards reducing the worst pain (SMD -0.28, 95% CI -0.57 to 0.01; I2=0% (95% CI 0% to 98%; p=0.06)). For the treatment setting, some studies have shown a potential therapeutic effect of gabapentinoids. However, the results are not consistent between studies. Given the studies' heterogeneity, a meta-analysis in treatment setting was not performed. CONCLUSION: There is limited evidence to support the use of gabapentinoids in CIPN. In prevention setting, gabapentinoids do not significantly prevent CIPN. In treatment setting, studies have been inconsistent in their conclusions, lacking definitive benefits over placebo. More comprehensive and higher quality research is needed in the future. PROSPERO REGISTRATION NUMBER: CRD42022361193.

The Association of Gabapentin Initiation with Cognitive and Behavioral Changes in Older Adults with Cognitive Impairment: A Retrospective Cohort Study.

BACKGROUND: Although gabapentin has been increasingly prescribed to older adults, the relation between gabapentin initiation and longer-term neurocognitive changes is not well understood. Thus, this study aimed to examine the association of gabapentin initiation with cognitive and motor function decline in older adult participants with cognitive impairment. METHODS: A retrospective cohort study was conducted using the National Alzheimer's Coordinating Center Uniform Data Set (2005-March 2023). Participants with cognitive impairment at the visit of gabapentin initiation (i.e., index visit) were included. Using the incidence density sampling method, up to nine non-users were randomly selected for each initiator. Cognitive decline over 1 year was defined as any increase in Clinical Dementia Rating global score (CDR®GLOB) or a 1-point increase in CDR® sum of boxes (CDR®SB). Functional status decline over 1 year was defined as at least a 3-point increase in the Functional Activities Questionnaire (FAQ) sum or a 0.3-point increase of mean of FAQ. Motoric decline over 1 year was defined as new clinician reports of gait disorder, falls, and slowness. To mitigate confounding and selection bias, joint stabilized inverse probability of treatment weights and censoring weights were used. Analyses compared index with index + 1 and index + 2 visits. RESULTS: For the study of cognitive and functional status decline, we included 505 initiators (mean age [SD] 78.8 [7.4]; male = 45%) and 4545 non-users (79.2 [7.6]; 50.1%). For the study of motor decline, we included 353 initiators (78.3 [7.2]; 42.8%) and 3177 non-users (78.5 [7.4]; 48.1%). Gabapentin initiation was not statistically associated with decline on CDR®GLOB, CDR®SB, FAQ sum, or mean FAQ at the index + 1 or index + 2 visits. However, gabapentin initiation was significantly associated with increased odds of new falls at the index + 2 visit (odds ratio [95% confidence interval] 2.5 [1.3, 4.6]). CONCLUSIONS: Over 1 or 2 years of follow-up, gabapentin initiation was not associated with decline in cognitive or functional status but was associated with increased odds of falling among research participants with cognitive impairment.

Medication-induced central sleep apnea: a unifying concept.

Medication-induced central sleep apnea (CSA) is one of the eight categories of causes of CSA but in the absence of awareness and careful history may be misclassified as primary CSA. While opioids are a well-known cause of respiratory depression and CSA, non-opioid medications including sodium oxybate, baclofen, valproic acid, gabapentin, and ticagrelor are less well-recognized. Opioids-induced respiratory depression and CSA are mediated primarily by µ-opioid receptors, which are abundant in the pontomedullary centers involved in breathing. The non-opioid medications, sodium oxybate, baclofen, valproic acid, and gabapentin, act upon brainstem gamma-aminobutyric acid (GABA) receptors, which co-colonize with µ-opioid receptors and mediate CSA. The pattern of ataxic breathing associated with these medications is like that induced by opioids on polysomnogram. Finally, ticagrelor also causes periodic breathing and CSA by increasing central chemosensitivity and ventilatory response to carbon dioxide. Given the potential consequences of CSA and the association between some of these medications with mortality, it is critical to recognize these adverse drug reactions, particularly because discontinuation of the offending agents has been shown to eliminate CSA.

Association of adverse cardiovascular events with gabapentin and pregabalin among patients with fibromyalgia.

OBJECTIVE: Fibromyalgia, a chronic pain disorder, impacts approximately 2% of adults in the US. Gabapentin and pregabalin are common treatments to manage fibromyalgia-related pain. Our recent study showed the risk of adverse cardiovascular events increased in diabetic neuropathy patients who were prescribed gabapentin or pregabalin. Here, we investigated whether the prescription of gabapentin or pregabalin has similar cardiovascular risk in patients with fibromyalgia. METHODS: This retrospective cohort study leveraged electronic health records from 64 US healthcare organizations with 112 million patients. The study population included 105,602 patients first diagnosed with fibromyalgia and followed by a prescription of gabapentin, pregabalin, or other FDA-approved drugs for treating fibromyalgia from 2010 to 2019. Outcomes were deep venous thrombosis (DVT), myocardial infarcts (MI), peripheral vascular disease (PVD), strokes, heart failure, and pulmonary embolism (PE). In propensity-score-matched cohorts, 1-year and 5-year hazard ratios (HRs) were computed with their respective 95% confidence intervals (CIs). Additionally, we conducted sensitivity analyses on the subpopulations without other possible indications. RESULTS: For 5-year follow-up, gabapentin increased the risk of PVD (HR = 1.46, 95% CI = 1.17-1.80), MI (HR = 1.31, 95% CI = 1.03-1.66), heart failure (HR = 1.27, 95% CI = 1.10-1.48), DVT (HR = 1.80, 95% CI = 1.33-2.44), and PE (HR = 2.23, 95% CI = 1.62-3.07). Pregabalin increased the risk of DVT (HR = 1.49, 95% CI = 1.01-2.20), and PE (HR = 2.24, 95% CI = 1.43-3.50). For 1-year follow-up, gabapentin increased the risk of PVD (HR = 1.32, 95% CI = 1.11-1.57), DVT (HR = 1.35, 95% CI = 1.09-1.68), and PE (HR = 1.36, 95% CI = 1.17-1.57). Pregabalin increased the risk of PVD (HR = 1.32, 95% CI = 1.06-1.63) and PE (HR = 1.25, 95% CI = 1.03-1.52). Sensitivity analyses showed similar trends. CONCLUSION: In fibromyalgia patients, the prescription of gabapentin and pregabalin moderately increased the risk of several adverse cardiovascular events. This risk, together with benefits and other adverse reactions, should be considered when prescribing these medications for fibromyalgia patients.

Exploring Analgesic Use Patterns Among Cancer Survivors With Chronic Chemotherapy-Induced Peripheral Neuropathy.

OBJECTIVES: To explore cancer survivors' historical and current use of analgesics for chronic chemotherapy-induced peripheral neuropathy (CIPN). SAMPLE & SETTING: 142 post-treatment cancer survivors who received neurotoxic chemotherapy and were experiencing moderate to severe CIPN. METHODS & VARIABLES: Participants completed the Treatment-Induced Neuropathy Assessment Scale at baseline and reported all analgesics used to manage CIPN. Frequency of historical or current prescription analgesic use for chronic CIPN was described and stratified by CIPN pain severity. RESULTS: At baseline, 31% of participants reported historical use of analgesics for CIPN and 46% of participants were currently using analgesics for CIPN. Gabapentin was the most frequently used analgesic, historically (20%) and currently (34%), and duloxetine was used less frequently (6% historical use, 10% current use). Many participants with severe pain (59%) reported using analgesics for CIPN. IMPLICATIONS FOR NURSING: Duloxetine, the first-line treatment for chronic CIPN pain, was used less frequently than gabapentin, a common prescription analgesic for neuropathic pain. Further research is needed to determine strategies to promote the implementation of evidence-based CIPN treatments in clinical practice.

A systematic review and meta-analysis of the effectiveness and adverse events of gabapentin and pregabalin for sciatica pain / Revisión sistemática y metaanálisis sobre la efectividad y eventos adversos de gabapentina y pregabalina para el dolor de ciática

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.DesignSystematic review.DatabasesElectronic 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 criteriaRandomized 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 treatmentThe 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.ResultsEight 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.ConclusionsThis 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.

Objetivo: Esta revisión sistemática evalúa la efectividad de pregabalina y gabapentina sobre el dolor y la discapacidad producidas por el dolor agudo causado por ciática, y los eventos adversos asociados al uso clínico.DiseñoRevisión sistemática.Bases de datosSe buscó en Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, y en Clinical Trials.gov desde su inicio hasta el 1 de marzo del 2021.Criterios de selecciónEnsayos clínicos aleatorizados (ECA) sobre adultos > 18 años con ciática aguda establecida entre una semana como mínimo y un año como máximo (al menos con dolor moderado).Tratamiento de datosLos resultados fueron dolor, discapacidad y eventos adversos. Los datos fueron resumidos usando odds ratio y diferencia de medias. Para calcular el nivel de evidencia se empleó GRADE.ResultadosSe incluyeron 8 ECA con un total de 747 participantes. El efecto de la pregabalina fue evaluado en 3 ECA y en un ensayo de 3 brazos (pregabalina vs. limaprost vs. una combinación de limaprost y pregabalina). Dos ensayos evaluaron el efecto de gabapentina comparado con placebo y uno lo comparó con tramadol. Un estudio evaluó el efecto de gabapentina vs. pregabalina en un ensayo cruzado.En un ECA se encontró una diferencia estadísticamente significativa en la mejora del dolor de piernas a las 2 semanas y en el dolor de piernas con el movimiento a los 3 y 4 meses, con gabapentina comparado frente a placebo. No hubo diferencias en el resto de los periodos estudiados para el dolor de piernas, dolor en la zona lumbar o en la discapacidad funcional.ConclusionesEsta revisión sistemática ofrece evidencia clara de la falta de pruebas sobre la efectividad de pregabalina o gabapentina para el manejo del dolor derivado de la ciática. Por tanto, su uso clínico rutinario no está avalado.

Effect of melatonin on the daytime sleepiness side-effect of gabapentin in adults patients with neuropathic pain / Efeito da melatonina sobre o efeito colateral de sonolência diurna da gabapentina em pacientes adultos com dor neuropática

Abstract Background and objectives: Gabapentin is an antiepileptic drug. Widely used for the management of neuropathic pain. Although it is known to be well tolerated, somnolence and dizziness are the most frequent adverse effects. In this study, we aimed to evaluate the effect of melatonin on daytime sleepiness side effect of gabapentin, sleep quality and pain intensity of patients with neuropathic pain. Methods: Patients suffering from "neuropathic pain" and planed to receive gabapentin therapy were randomly divided into two groups. Group 1 received melatonin 3 mg and gabapentin 900 mg orally, group 2 received matching placebo capsule and gabapentin 900 mg. The Epworth Sleepiness Scale, the Pittsburgh sleep quality index for assessment of sleep quality and Verbal Rating Scale were completed at the 0th, 10th and 30th days of treatment. Additive analgesic drug requirements were recorded. Results: Eighty patients were enrolled to the study; age, gender, ratio of additive analgesic consumption, baseline Epworth Sleepiness Scale, Pittsburg Sleep Quality index and Verbal Rating Scale scores were similar between the groups. Epworth Sleepiness Scale scores, Pittsburgh sleep quality index scores and Verbal Rating Scale scores in Group 1 were significantly lower than group 2 at the 10th day of treatment (p = 0.002, p = 0.003, p = 0.002 respectively). At the 30th day of treatment, Epworth Sleepiness Scale scores and Verbal Rating Scale scores were significantly lower in Group 1 (p = 0.002, p = 0.008 respectively). However, Pittsburgh sleep quality index scores did not significantly differ between the groups (p = 0.0566). Conclusions: Melatonin supplementation rapidly and significantly improved daytime sleepiness side-effect of gabapentin, however sleep quality of the patients with neuropathic pain was similar between groups.

Resumo Justificativa e objetivos: Gabapentina é um agente antiepiléptico, amplamente utilizado para o tratamento da dor neuropática. Embora conhecida por ser bem-tolerada, sonolência e tontura são os seus efeitos adversos mais frequentes. Neste estudo, nosso objetivo foi avaliar o efeito da melatonina sobre o efeito colateral de sonolência diurna da gabapentina, a qualidade do sono e a intensidade da dor em pacientes com dor neuropática. Métodos: Os pacientes que sofriam de "dor neuropática" e com prescrição para receber terapia com gabapentina foram divididos aleatoriamente em dois grupos. O Grupo 1 recebeu 3 mg de melatonina e 900 mg de gabapentina por via oral, o Grupo 2 recebeu uma cápsula de placebo correspondente e 900 mg de gabapentina. A escala de sonolência de Epworth (ESS), o índice de qualidade do sono de Pittsburgh para avaliação da qualidade do sono (PSQI) e a escala de avaliação verbal (VRS) foram aplicados nos dias 0, 10 e 30 de tratamento. A necessidade de medicamentos analgésicos adicionais foi registrada. Resultados: Oitenta pacientes foram incluídos no estudo; idade, sexo, quantidade de analgésico adicional consumida e os escores basais de ESS, PSQI e VRS foram semelhantes entre os grupos. Os escores ESS, PSQI e VRS do Grupo 1 foram significativamente menores que os do Grupo 2 no décimo dia de tratamento (p = 0,002, p = 0,003, p = 0,002, respectivamente). No trigésimo dia de tratamento, os escores ESS e VRS foram significativamente menores no Grupo 1 (p = 0,002, p = 0,008, respectivamente). No entanto, os escores PSQI não diferiram significativamente entre os grupos (p = 0,0566). Conclusões: A suplementação de melatonina melhorou de forma rápida e significativa o efeito colateral de sonolência diurna da gabapentina, mas a qualidade do sono dos pacientes com dor neuropática foi semelhante entre os grupos.