#375 Pharm for Fibro: Can antidepressants ease the pain?
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- Seven systematic reviews of randomized, placebo-controlled trials (RCTs) in the last 10 years. Ages 42-53, >90% women. Statistically significant unless indicated.
- Duloxetine: 4 systematic reviews (6-7 RCTs, 2249-2642 patients).1-4 At 8-27 weeks:
- Proportion of patients with ≥30% reduction in pain:1 48% versus 36%, number needed to treat (NNT)=9.
- 30mg versus placebo: No difference.2
- 60-120mg: ~50% versus 35% (placebo).2
- Proportion with >50% reduction in pain:1 34% versus 23%, NNT=9.
- Withdrawal due to adverse events: No difference.1
- Exception: 120mg dose; 21% versus 11% (placebo), number needed to harm=10.
- Adverse effects: include nausea (26%), constipation (15%), headache (14%) versus 4-8% placebo; hyperhidrosis 8% versus 1% placebo.1
- Other reviews found similar.2-4
- Proportion of patients with ≥30% reduction in pain:1 48% versus 36%, number needed to treat (NNT)=9.
- Mirtazapine: One systematic review (3 RCTs, 591 patients, average 30mg daily).5 At 7-14 weeks:
- >30% pain reduction: 47% versus 34% (placebo), NNT=8.
- ≥ 50% pain reduction: No difference.
- Adverse event withdrawals: No difference.
- Adverse effects include:
- Somnolence: 41% versus 14% (placebo).
- Any weight gain: 19% versus 1% (placebo).
- SSRIs (fluoxetine, citalopram, paroxetine): One systematic review (7 RCTs, 383 patients).6 At 6-16 weeks:
- ≥30% reduction in pain: 33% versus 23% (placebo), NNT=10.
- Adverse event withdrawals: no difference.
- Amitriptyline: One systematic review (4 RCTs, 275 patients, 25-50mg daily).7 At 8-24 weeks:
- >50% pain reduction: 36% versus 11%, NNT=5.
- Adverse event withdrawals and adverse events: No difference.
- Limitations: Minimal reporting of patient function,1-3,5-8 small studies of short duration,6,7 majority industry funded,2,3,5 blinding uncertain.5
- Diagnosis requires chronic diffuse pain >3 months.8
- Specific tender point distribution no longer needed.8
- Specialist diagnosis/treatment or extensive investigations not required.8
- Exercise and cognitive behavioural therapy can improve pain and mobility.9
- 90-day cost:10 Duloxetine 60mg ~$100; mirtazapine 30mg ~$35.
Helpful re mirtazepine and pain effects
informative
A great tool
Consistent with my
This is consistent with my experience