A Cochrane review [Abstract] 1 includes 23 trials with a total of 1586 subjects. Fifty-eight per cent of them were from 5 unpublished studies. Twenty trials investigated idiopathic muscle cramps. Quinine was compared to placebo (20 trials, n =1140), vitamin E (4 trials, n = 543), a quinine-vitamin E combination (3 trials, n = 510), a quinine-theophylline combination (one trial, n = 77), and xylocaine injections into the gastrocnemius muscle (one trial, n = 24). Most of the trials used a daily quinine dose of 300 mg (range 200 to 500 mg).The duration of treatment ranged from 5 to 42 days. Compared to placebo, quinine significantly reduced cramp number over two weeks by 28%, cramp intensity by 10%, and cramp days by 20%. Cramp duration was not significantly affected (14 trials, n = 982).A significantly greater number of people suffered minor adverse events on quinine (risk difference +3%, 95% CI 0% to 6%), mainly gastrointestinal symptoms. A quinine-vitamin E combination, vitamin E alone, and xylocaine injections into gastrocnemius were not significantly different to quinine, including adverse effects. Based on a single trial comparison, quinine alone was significantly less effective than a quinine-theophylline combination but with no significant differences in adverse events.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment).
Primary/Secondary Keywords