RANDOMIZED CONTROLLED TRIAL OF HYDROQUININE IN MUSCLE CRAMPS

Background Although quinine and hydroquinine are commonly prescribed f or muscle cramps, controlled clinical trials of these drugs have repor ted mixed findings about efficacy. We investigated hydroquinine therap y in otherwise healthy adults who had frequent, ordinary muscle cramps . Methods This randomised, double-blind, placebo-controlled, parallel- group trial consisted of three consecutive 2-week periods: qualificati on, treatment, and washout. 68 women and 44 men who had at least three muscle cramps per week were enrolled. During the treatment period, pa rticipants were randomly assigned 300 mg daily dose of hydroquinine hy drobromide dihydrate (54 participants) or placebo (58). The frequency, severity (1-10), duration, and location of muscle cramps, as well as any side-effects, were recorded by participants in daily diaries. The primary outcome measures were the number of muscle cramps and the numb er of days during which the participants had muscle cramps (cramp-days ). Findings We excluded five participants from both groups from the an alysis. Thus, data from 49 hydroquinine-group participants and 53 plac ebo-group participants were analysed. In both groups the total number of muscle cramps and the number of cramp-days decreased during the tre atment period compared with the qualification period. However, these i mprovements were greater in the hydroquinine group than in the placebo group. The hydroquinine-group participants reported a median of 8 (95 % CI 7-12) fewer cramps and median of 3 (1-4) fewer cramp-days, wherea s those on placebo reported only 3 (0-5) fewer cramps and 1 (0-5) fewe r cramp-days. 32 (65%) of participants in the hydroquinine group had a 50% or greater reduction in the number of muscle cramps. After the on set of cramps, hydroquinine did not reduce the severity or duration of cramps. We also found a sustained effect after treatment had stopped. Hydroquinine was well tolerated, and resulted in only mild side-effec ts. Interpretation In our study, 300 mg hydroquinine was safe to take in the short-term and significantly more effective than placebo in the prevention of frequent, ordinary muscle cramps. this therapeutic effe ct outlasted the duration of treatment.