Limited Efficacy of Muscle Relaxants for Chronic Pain Save

A systematic review of long-term muscle relaxant use for chronic pain suggests they may be effective in treating trigeminal neuralgia, cramps, and neck pain, but not fibromyalgia, low back pain, and other pain syndromes.

The importance of this issue has grown with stricter opioid prescribing guidelines in recent years.

A systematic review included 30 RCTs (1314 participants) and 14 cohort studies (1168 participants) receiving 9 different muscle relaxants for chronic pain, usually in short-term (4-6 weeks) trials. Nine unique SMRs were represented by the studies identified. Eleven studies (25%) examined baclofen, 8 (18%) examined tizanidine, and 7 (16%) examined cyclobenzaprine. 

Strong evidence for effectiveness (better than placebo effect) was demonstrated for trigeminal neuralgia, neck pain, and painful cramps. 

Muscle relaxants were not more beneficial than placebo in treating fibromyalgia, low back pain, headache or other pain syndromes. 

The most common adverse effects were sedation and dry mouth.