Comment: The strength of recommendation is downgraded by unknown balance of benefit and harm, and lack of information on comparative effectiveness with other drugs for neuropathic pain.
Summary
A Cochrane review «Gabapentin for chronic neuropathic pain in adults»1 «Wiffen PJ, Derry S, Bell RF et al. Gabapentin for chronic neuropathic pain in adults. Cochrane Database Syst Rev 2017;(6):CD007938. »1 included 37 studies with a total of 5914 subjects. Gabapentin was studied at daily doses of 1200 mg or more in different neuropathic pain conditions, predominantly postherpetic neuralgia and painful diabetic neuropathy.
In postherpetic neuralgia, more participants (32%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (17%) (RR 1.8 (95% CI 1.5 to 2.1); NNT 6.7 (5.4 to 8.7); 8 studies, 2260 participants). More participants (46%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (25%) (RR 1.8 (95% CI 1.6 to 2.0); NNT 4.8 (4.1 to 6.0); 8 studies, 2260 participants).
In painful diabetic neuropathy, more participants (38%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (21%) (RR 1.9 (95% CI 1.5 to 2.3); NNT 5.9 (4.6 to 8.3); 6 studies, 1277 participants). More participants (52%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (37%) (RR 1.4 (95% CI 1.3 to 1.6); NNT 6.6 (4.9 to 9.9); 7 studies, 1439 participants).
Serious adverse events were no more common with gabapentin (3.2%) than with placebo (2.8%) (RR 1.2 (95% CI 0.8 to 1.7); 19 studies, 3948 participants); there were eight deaths. Participants experiencing at least one adverse event were more common with gabapentin (63%) than with placebo (49%) (RR 1.3 (95% CI 1.2 to 1.4); NNH 7.5 (6.1 to 9.6); 18 studies, 4279 participants). Individual adverse events occurred significantly more often with gabapentin. Participants taking gabapentin experienced dizziness (19%), somnolence (14%), peripheral oedema (7%), and gait disturbance (14%).
| Condition, At least 50% pain intensity reduction | Studies | Patients | Benefit gabapentin % | Benefit placebo % | RR, 95 % Cl |
|---|---|---|---|---|---|
| PHN Postherpetic neuralgia | 7 | 2031 | 33 | 19 | 1.7 (1.4 to 2.0) |
| PDN Painful diabetic neuropathy | 6 | 1331 | 38 | 23 | 1.7 (1.4 to 2.0) |