FDA: Don't Use Quinine for Leg Cramps

FDA Cracks Down on Unapproved Quinine Drugs, Cites Problems Including Deaths

Medically Reviewed by Louise Chang, MD on December 12, 2006

Dec. 12, 2006 -- The FDA is telling people not to use the malaria drug quinine for leg cramps, citing potentially deadly side effects.

The FDA issued the advice today and ordered all unapproved drugs containing quinine off the market within 60 days.

Qualaquin, the only FDA-approved quinine drug, can be used to treat certain types of malaria; the new order doesn't change that.

But quinine is also often prescribed to treat leg cramps. That unapproved use is too risky, says the FDA.

Quinine carries extensive warnings about possible side effects, including:

  • Potentially serious interactions with other drugs
  • Abnormal heart rhythms
  • Thrombocytopenia, a blood platelet disorder that can cause hemorrhage or clotting problems
  • Severe hypersensitivity reactions

Since 1969, the FDA has received 665 reports of serious adverse events tied to quinine, including 93 deaths.

Quinine has a narrow margin between effective and toxic doses, notes the FDA.

The doses for Qualaquin have the FDA's approval for treatment of certain types of malaria. But the FDA hasn't reviewed dosing for unapproved quinine drugs.

"We believe unapproved quinine products represent a serious health risk because of the widespread use of this product for treating leg cramps," Steven Galson, MD, MPH, says in the FDA news release. Galson directs the FDA's Center for Drug Evaluation and Research.

"Quinine needs to be dosed carefully, and FDA-approved labeling reflects the fact that the risks associated with the use of this drug for treatment of leg cramps outweigh the benefits," Galson says.