A systematic review and network meta-analysis estimated the effect of pregabalin in fibromyalgia related pain and found small impact «Farag HM, Yunusa I, Goswami H, et al. Comparison o...»1. By reanalyzing the included studied, we estimated the effect to be about 11% decrease in pain at 8-14 weeks follow up (0.56 points on scale 0-10). The same review found little to no impact on fibromyalgia-related quality of life, but the evidence was more uncertain.
A Cochrane review found increased withdrawals due to adverse events with a dose-response (higher doses leading to higher withdrawals) «Derry S, Cording M, Wiffen PJ, et al. Pregabalin f...»2. Another systematic review estimated specific harms for any condition «Zaccara G, Gangemi P, Perucca P, et al. The advers...»3. For 300mg per day dose the risk differences (95 % confidence interval) were: dizziness 0.21 (0.19 to 0.24), Vertigo 0.05 (0.02 to 0.07), ataxia 0.04 (0.00 to 0.08), blurred vision 0.04 (0.02 to 0.05), amblyopia 0.03 (0.00 to 0.06), somnolence 0.14 (0.12 to 0.16), edema 0.08 (0.02 to 0.18) dry mouth 0.05 (0.03 to 0.06), and constipation 0.03 (0.01 to 0.04). Harms had dose-response, meaning that higher doses likely lead to more harms.
The evidence was limited by high risk of bias.
| Reference | Study type | Population | Intervention and comparison | Outcomes | Risk of bias |
|---|---|---|---|---|---|
| RCT=randomized controlled trial; SR=systematic review; MA=meta-analysis; NMA=network meta-analysis | |||||
| «Farag HM, Yunusa I, Goswami H, et al. Comparison o...»1 | SR/NMA | Adults with fibromyalgia | Pregabalin vs placebo | Mean pain intensity, sleep problems, fibromyalgia-related quality of life | High |
| «Derry S, Cording M, Wiffen PJ, et al. Pregabalin f...»2 | SR/MA | Adults with fibromyalgia | Pregabalin vs placebo | Withdrawals due to adverse events | High |
| Reference | Comments |
|---|---|
| «Farag HM, Yunusa I, Goswami H, et al. Comparison o...»1 | High dropout rates. Randomization and blinding ok. |
| «Derry S, Cording M, Wiffen PJ, et al. Pregabalin f...»2 | Same trials than in the previous review, but estimated withdrawals due to adverse events, not estimated in the previous review. |
| Reference | Number of studies and number of patients | Follow-up time | Mean change from baseline (sd) I | Mean at follow up C | Mean difference (95% CI) |
|---|---|---|---|---|---|
| Level of evidence: moderate The quality of evidence is downgraded due to study limitations. I=intervention; C=comparison; CI=confidence interval *Estimated with reanalysis of the included studies (random effects meta-analysis). Conversion with weighted average sd gives similar MD (0.54 for 600mg). |
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| «Farag HM, Yunusa I, Goswami H, et al. Comparison o...»1 | 7 studies, 3982 patients | 8-14 weeks | - | - | SMD for 300mg: -0.23 (-0.26 to -0.21) SMD for 450mg: -0.30 (-0.32 to -0.27) SMD for 600mg: -0.27 (-0.30 to -0.25) MD for 300-600mg: -0.56 (-0.72 to -0.4)* Relative decrease: -11 % (-14 % to -0.8 %)* |
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Mean change from baseline (sd) I | Mean at follow up C | Mean difference (95% CI) |
|---|---|---|---|---|---|
| Level of evidence: low The quality of evidence is downgraded due to study limitations and imprecision. I=intervention; C=comparison; CI=confidence interval |
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| «Farag HM, Yunusa I, Goswami H, et al. Comparison o...»1 | 7 studies, 3982 patients | 8-14 weeks | - | - | SMD for 300mg: -0.14 (-0.23 to 0.09) SMD for 450mg: -0.18 (-0.29 to -0.06) SMD for 600mg: -0.11 (-0.23 to 0.01) |
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Events I (%) | Events C (%) | Relative risk (95% CI) |
|---|---|---|---|---|---|
| Level of evidence: High I=intervention; C=comparison; CI=confidence interval |
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| «Derry S, Cording M, Wiffen PJ, et al. Pregabalin f...»2 | 5 studies | 8-14 weeks | 300mg: 113 (16.5%) 450mg: 163 (17.4%) 600mg: 159 (28%) |
80 (8.5%) | RR for 300mg: 1.58 (1.20 to 2.08) RR for 450mg: 2.04 (1.59 to 2.62) RR for 600mg: 2.54 (1.94 to 3.32) |