#381 Pharm for Fibro, Round 2: Can gabapentinoids ease the pain?

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- Statistically significant unless indicated.
- Pregabalin versus placebo: 1 systematic review (5 RCTs, 3283 patients, 150-600mg daily). At 8-14 weeks:1
- Proportion of patients with ≥30% reduction in pain:
- 150mg: no difference.
- 300-600mg: 39-43% versus 29% (placebo), Number Needed to Treat (NNT)~8-10.
- Adverse event withdrawals:
- 150mg: no difference.
- 300-600mg: 17-28% versus 10% (placebo), Number Needed to Harm (NNH)=6-15.
- Some adverse effects increased with higher doses. Examples:
- Dizziness: 32% (300mg) versus 46% (600mg) versus 10% (placebo), NNH~3-5.
- Peripheral edema: 6.5% (300mg) versus 11% (600mg) versus ~2% (placebo) NNH=11-23.
- Proportion of patients with ≥30% reduction in pain:
- Pregabalin 150mg versus duloxetine 60mg: One RCT, 66 patients. At 4 weeks:2
- Number of pain sites (up to 19 possible sites, baseline~8): reduced to 6.3 (pregabalin) versus 4 (duloxetine).
- Pregabalin (300-450mg) added to antidepressants: One RCT, 181 patients on various anti-depressants. At 6 weeks:3
- Proportion with ≥30% pain reduction: 45% (pregabalin add-on) versus 28% (no add-on), NNT=6.
- Gabapentin: 1 publicly funded RCT, 150 patients, 1200-2400mg/day. After 12 weeks:4
- Proportion with ≥30% pain reduction: 51% versus 31% (placebo), NNT=5.
- Global improvement: 68% versus 35% (placebo), NNT=3.
- Adverse events:
- Withdrawal due to adverse events: No difference.
- Sedation: 24% versus 4% (placebo); dizziness 25% versus 9% (placebo). NNH=5-7.
- Limitations: All pregabalin studies were industry funded. Most studies excluded patients on antidepressants.
- Canadian guidelines: Antidepressant medications can be used based on individual presentation and anticonvulsants can be tried, up-titrating as tolerated.5
- Depression is present in about 22% patients with fibromyalgia.6
- Duloxetine and mirtazapine reduce pain by ≥30% in ~50% of patients with fibromyalgia versus 35% placebo.7
- 90-day costs:8 pregabalin 300mg ~$95; gabapentin 900mg ~$45.
Will consider using higher doses of Pregabalin in the appropriate situation.
Helpful information.