A systematic review «Soliman N, Moisset X, Ferraro MC, ym. Pharmacother...»1 measured effectiveness of Gabapentinoids on neuropathic pain including 56 randomized trials. A reanalysis of these trials suggested mean 0.67 points decrease (95% CI -0.83 to -0.51) in average pain at 4-16 weeks follow up, translating to about 13 % decrease in pain (95% CI -17 % to -10 %).
In a subgroup analysis pregabalin (300-600mg; mean difference -0.70, 95% CI -0.94 to -0.47) had very similar effect compared to gabapentin (1600-3600mg; mean difference -0.67, 95% CI -0.83 to -0.51).
The same systematic review found RD of 3.8 % (2.7 % to 4.9 %) for withdrawals due to side effects.
A Cochrane review «Derry S, Bell RF, Straube S, ym. Pregabalin for ne...»2measured harms for Pregabalin 300mg and suggested an increase in risk of somnolence (RD 8%; RR 3,.34 [2.62-4.26]) and dizziness (RD 12%, RR 3.53 [2.86-4.35]). Other specific adverse events were not reported. However, another systematic review «Zaccara G, Gangemi P, Perucca P, ym. The adverse e...»3 estimated other adverse events on any condition and found also increased risk of Vertigo (5 %), ataxia (4 %), blurred vision (4 %), peripheral edema (5 %), dry mouth (5 %) and constipation (3 %). The risk of adverse events is likely correlated with the dose.
The quality of evidence was downgraded due to high risk of bias (high dropout rates).
| Reference | Study type | Population | Intervention and comparison | Outcomes | Risk of bias |
|---|---|---|---|---|---|
| RCT=randomized controlled trial; SR=systematic review; MA=meta-analysis | |||||
| «Soliman N, Moisset X, Ferraro MC, ym. Pharmacother...»1 | SR/MA | Adult patients with neuropathic pain | Gabapentinoids vs placebo | Decrease in average pain | High |
| Reference | Comments |
|---|---|
| «Soliman N, Moisset X, Ferraro MC, ym. Pharmacother...»1 | Most trials were at high risk of bias (mainly due to over 20 % dropout rates). From all trials, 42 tested pregabalin, 23 gabapentin, and 5 mirogabalin. |
Results
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Mean (SD) I | Mean (SD) C | Mean difference (95% CI) |
|---|---|---|---|---|---|
| Level of evidence: Moderate The quality of evidence was downgraded one time due to high risk of bias and inconsistency combined. *We calculated the effect size by using the data provided by the systematic review. We used random effects meta-analysis. We excluded 9 small trials included in the original review due to insufficient data and excluded small doses (under 1600mg for gabapentin and under 300mg for pregabalin). I= intervention; C=comparison; CI=confidence interval |
|||||
| «Soliman N, Moisset X, Ferraro MC, ym. Pharmacother...»1 | 44 trials, 2699 patients | 4-14 weeks | Not reported | 5.02 | -0.67 (-0.83 to -0.51)* Relative effect: -13 % (-17 % to -10 %) |