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Nocturnal Leg Cramps

 

Check out the updated version of this story (June 2001) here

Leg cramps at night are common in elderly people, with perhaps 70% having leg cramps at some time. Quinine was first used over 50 years ago, and it has been suggested that it is the most beneficial form of treatment. The problem has been that trials of quinine in leg cramps have tended to use relatively small treatment groups and short treatment times, and there have been relatively few of them. The result has been uncertainty about whether prescribing quinine for patients with leg cramps was beneficial.

Meta-analysis

This uncertainty has been resolved by a recently published meta-analysis published in the British Medical Journal [1]. The authors searched for randomised controlled trials (RCTs) which had a double-blind, placebo-controlled, crossover design, and which were conducted in ambulatory elderly patients.

They found 11 such papers, but rejected five because they did not comply fully with their inclusion criteria. The six papers accepted had only 107 patients in all on whom individual data could be used in a meta-analysis to determine whether quinine was effective in reducing the number of cramps, their severity or duration, and the number of nights with cramps.

The doses of quinine used were 200 mg - 300 mg daily, usually taken in the evening or at bedtime.

Results

The meta-analysis showed :-
  • A significant reduction in the number of cramps in people taking quinine. Over four weeks, they had almost 9 fewer cramps (95% confidence interval 4 - 13 cramps). This reduction in cramp numbers was even higher (nearly 13 cramps fewer) when a parallel group comparison of quinine and placebo was added to the analysis.
  • A significant reduction in the number of nights free of cramps in people taking quinine. Over four weeks, there were almost 30% fewer nights with cramps.
  • Studies with treatment times of four weeks had more positive results than those with two weeks. This suggests that dosing is cumulative, and a four-week trial may be necessary to show a beneficial effect, and indicates that quinine, to be effective, should be taken regularly.
  • Quinine did not affect the severity of individual cramps or their duration when leg cramps occurred.
  • Adverse events were uncommon, and only one patient had a severe reaction. Numbers of people studied were too few to characterise adequately the incidence of uncommon adverse effects.

This is an interesting meta-analysis, and the authors clearly show some of the difficulties encountered in amalgamating information. It's worth a read.

Reference:

M Man-Son-Hing, G Wells. Meta-analysis of efficacy of quinine for treatment of nocturnal leg cramps in elderly people. British Medical Journal 1995 310: 13-7.



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