NEW YORK, Feb 21 (Reuters) -- For decades, doctors have treated muscle cramps with quinine and hydroquinine, drugs which have a similar action as curare -- the muscle-paralyzing substance once used in poison-tipped darts.
However, the few studies of quinine treatment -- which can have serious side effects such as deafness, headache and ringing in the ears -- were small and poorly designed, according to researchers.
Now, a new study has confirmed that, yes, the drugs are safe and do appear to relieve muscle cramps, a problem that afflicts about 2% of the population on a weekly basis.
According to the report in this week's issue of The Lancet, those individuals taking 300 milligrams of hydroquinine during a two-week period had a median of eight fewer cramps, and three fewer days when they experienced cramps, than before treatment.
In comparison, those taking a placebo, or dummy medication, experienced three fewer cramps, and one less day of experiencing cramps than before treatment. Even after halting medication, those taking hydroquinine had fewer cramps the following week.
"The results of this study confirmed that a daily dose of 300 milligram hydroquinine dihydrate is safe to take on a short-term basis, and is significantly more effective than placebo in the prevention of frequent, ordinary muscle cramps in otherwise healthy adults," wrote senior investigator Professor A. Verbeek, of the Catholic University of Nijmegen in The Netherlands.
In the study of 102 individuals -- 49 of whom took hydroquinine, and 53 who took placebo -- the side effects were few and fairly mild. Ten people complained of the bitter taste of the drug, and there was one case of tinnitus, or ringing in the ears. Only one woman had to stop taking the drug because of nausea and the bitter taste.
Hydroquinine does not stop a cramp in progress. Instead, it seems to be more effective at reducing the cycle that causes them to occur.
"We believe that the drug should be prescribed on a regular, rather than on an as-needed basis," the authors concluded.
SOURCE: The Lancet (1997;349:528-532)
