Effect of Gabapentin vs Pregabalin on Pain Intensity in Adults With Chronic Sciatica

Abstract

IMPORTANCEOptimal pharmacologic treatment for chronic sciatica (CS) is currently unclear. While gabapentin (GBP) and pregabalin (PGB) are both used to treat CS, equipoise exists. Nevertheless, pharmaceutical regulation authorities typically subsidize one drug over the other. This hinders interchange wherever the favored drug is either ineffective or ill-tolerated.OBJECTIVE To assess GBP vs PGB head to head for the treatment of CS. DESIGN, SETTING, AND PARTICIPANTSA preplanned interim analysis of a randomized, double-blind, double-dummy crossover trial of PGB vs GBP for management of CS at half the estimated final sample size was performed in a single-center, tertiary referral public hospital. A total of 20 patients underwent randomization from March 2016 to March 2018, and 2 were excluded with 1 lost to follow-up and the other requiring urgent surgery unrelated to the study. Patients attending a specialist neurosurgery clinic with unilateral CS were considered for trial recruitment. Chronic sciatica was defined as pain lasting for at least 3 months radiating into 1 leg only to, at, or below the knee level. Imaging (magnetic resonance imaging with or without computed tomography) corroborating a root-level lesion concordant with symptoms and/or signs was determined by the trial clinician. Inclusion criteria included patients who had not used GBP and PGB and were 18 years or older. Analyses were intention to treat and began February 2018.INTERVENTIONS Randomly assigned participants received GBP (400 mg to 800 mg 3 times a day) then PGB (150 mg to 300 mg twice daily) or vice versa, each taken for 8 weeks. Crossover followed a 1-week washout. MAIN OUTCOMES AND MEASURESThe primary outcome was pain intensity (10-point visual analog scale) at baseline and 8 weeks. Secondary outcomes included disability (using the Oswestry Disability Index) and severity/frequency of adverse events. RESULTSThe total trial population (N = 18) consisted mostly of men (11 [61%]) with a mean (SD) age of 57 (16.5) years. A third of the cohort were smokers (5 [28%]), and more than half consumed alcohol (12 [67%]). Gabapentin was superior to PGB, with fewer and less severe adverse events. Both GBP (mean [SD], 7.54 [1.39] to 5.82 [1.72]; P < .001) and PGB (mean [SD], 7.33 [1.30] to 6.38 [1.88]; P = .002) displayed significant visual analog pain intensity scale reduction and Oswestry Disability Index reduction (mean [SD], 59.22 [16.88] to 48.54 [15.52]; P < .001 for both). Head to head, GBP showed superior visual analog pain intensity scale reduction (mean [SD], GBP: 1.72 [1.17] vs PGB: 0.94 [1.09]; P = .035) irrespective of sequence order; however, Oswestry Disability Index reduction was unchanged. Adverse events for PGB were more frequent (PGB, 31 [81%] vs GBP, 7 [19%]; P = .002) especially when PGB was taken first.CONCLUSIONS AND RELEVANCE Pregabalin and GBP were both significantly efficacious. However, GBP was superior with fewer and less severe adverse events. Gabapentin should be commenced before PGB to permit optimal crossover of medicines.

Dual‐trajectories of opioid and gabapentinoid use and risk of subsequent drug overdose among Medicare beneficiaries in the United States: a retrospective cohort study

“…Recently, several clinical trials have suggested the efficacy of GABA use for off-label pain conditions (e.g. chronic sciatica; irritable bowel syndrome) and for reducing acute and chronic postoperative pain and OPI use [50][51][52][53][54][55]. However, given the safety concerns about GABAs, there have been calls for placing more stringent regulations on gabapentin at the federal level and to include gabapentin monitoring in state prescription drug monitoring programs (PDMPs) to promote safety.…”

Pharmacotherapeutic Options for Managing Neuropathic Pain: A Systematic Review and Meta-Analysis

“…The effect size of pregabalin and its clinical usefulness are currently sources of debate [ 46 , 47 ]. Recent recommendations issued by the French chapter of the IASP and the French Society of Neurology [ 46 ] have proposed pregabalin as an alternative to gabapentin for second-line treatment, given that different studies [ 3 , 48 ] have shown that gabapentin has a relatively large effect size and tolerability.…”

Current and future pharmacological agents for the treatment of back pain

“…There have also been concerns about misuse, diversion, and dependence with long-term use of these medications. These medications may have a theoretical role in patients whose LBP has a strong neuropathic component [24], but the number needed to treat is high. A medication trial period of up to 4 weeks at therapeutic doses followed by cessation in absence of benefit is reasonable.…”