JAMA — Robertson K, et al. | January 15, 2019
Researchers investigated gabapentin (GBP) vs pregabalin (PGB) head to head for the treatment of chronic sciatica (CS). As per findings, both pregabalin and GBP were significantly efficacious. However, fewer and less severe adverse events noted with GBP support its superiority. They recommend initiating gabapentin before PGB to permit optimal crossover of medicines.
Methods
- In a single-center, tertiary referral public hospital, researchers performed a 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.
- From March 2016 to March 2018, randomization was done of a total of 20 patients; 2 were excluded with 1 lost to follow-up and the other requiring urgent surgery unrelated to the study.
- They recruited patients attending a specialist neurosurgery clinic with unilateral CS in this trial.
- They defined chronic sciatica as pain lasting for at least 3 months radiating into 1 leg only to, at, or below the knee level.
- The trial clinician determined the imaging (magnetic resonance imaging with or without computed tomography) corroborating a root-level lesion concordant with symptoms and/or signs.
- Patients who had not used GBP and PGB and were 18 years or older were eligible for inclusion.
- They performed intention to treat analysis that began in February 2018.
- Participants were randomly assigned to receive 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.
- Pain intensity (10-point visual analog scale) at baseline and 8 weeks was assessed as the primary outcome.
- Disability (using the Oswestry Disability Index) and severity/frequency of adverse events were assessed as the secondary outcomes.
Results
- Mostly men (11 [61%]) comprised the total trial population (N = 18) with a mean (SD) age of 57 (16.5) years.
- In this cohort, about one third of the participants were smokers (5 [28%]), and more than half consumed alcohol (12 [67%]).
- Compared to PGB, gabapentin was superior 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) led to a marked reduction in visual analog pain intensity scale and Oswestry Disability Index (mean [SD], 59.22 [16.88] to 48.54 [15.52]; P < .001 for both).
- Head to head, superior visual analog pain intensity scale reduction (mean [SD], GBP: 1.72 [1.17] vs PGB: 0.94 [1.09]; P=.035) was evident with GBP irrespective of sequence order; however, Oswestry Disability Index reduction was unchanged.
- PGB led to more frequent adverse events (PGB, 31 [81%] vs GBP, 7 [19%]; P=.002) especially when it was taken first.