Quinine sulfate for leg cramps: does it work?

Abstract

Objective: To study the efficacy of quinine in the prevention of nocturnal leg muscle cramps.

Design: Double-blind, randomized, crossover trial with four periods of observation, each lasting 2 weeks.

Setting: General internal medicine outpatient clinic.

Participants: Ambulatory outpatients who experienced an estimated two or more typical nocturnal leg cramps per week.

Intervention: 200 mg of quinine taken at bedtime.

Main outcome measures: Self-reported ratings of leg cramp frequency, duration, and intensity.

Results: Sixteen patients completed the trial. During the 2 weeks patients used quinine, there was no statistically significant reduction in mean leg cramp number (quinine 3.5 vs placebo 4.2, P = 0.48), mean leg cramp duration (quinine 152 seconds vs placebo 163 seconds, P = 0.89), or patient ratings of severity using a 1 (low) to 10 (high) scale (quinine = 4.2 vs placebo = 4.0, P = 0.83).

Conclusion: No significant reduction in nocturnal leg cramp frequency, intensity, or duration could be found using nightly quinine in this study. Since quinine is not without the potential for side effects and drug interactions, clinicians need to carefully consider the likelihood of modest benefit associated with quinine against the potential for side effects and drug-drug interactions.