The Food and Drug Administration on Thursday cautioned consumers against using quinine for leg cramps, warning that the drug could cause severe side effects, including death. Quinine, sold in this country under the brand name Qualaquin, is approved for treatment of uncomplicated malaria, but has a long history of use as a remedy for leg cramps, especially at night. In many countries, it is sold over the counter. Studies have shown that it can reduce the incidence of cramps by one-third to one-half but that as many as one in every 25 users can suffer serious side effects.
In a new warning to health professionals, the FDA said that between April 2005 and Oct. 1, 2008, it had received 38 reports of severe adverse events associated with the drug, including two deaths. Twenty-one patients had to be hospitalized because of severe bleeding due to a loss of blood cells called platelets -- a condition called thromobocytopenia -- and an additional 12 had bleeding in their mucosa. The agency believes many similar events went unreported.
The agency is initiating what is known as a Risk Evaluation and Mitigation Strategy that will require, among other things, that the manufacturer send a letter to healthcare professionals warning about the risks of unapproved use of quinine and that pharmacies be required to provide consumers with a medication guide illustrating what the drug is approved for and pointing out the potential side effects.