A systematic review including 7 RCTs with a total of 419 subjects was abstracted in DARE. The pooled OR for self-reported improvement was 3.85 (95% CI 2.22 to 6.67). Adverse effects necessitated 8 withdrawals. Reported adverse effects included hypertension, loss of anti-epileptic action of phenytoin, rash, anxiety, dizziness, increased urinary frequency, chills, headache, sweating, agitation, tachycardia, gastrointestinal disturbances, diarrhoea and lethargy.
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in results in different populations).
Another meta-analysis see reference .