Life-Threatening Side Effects With Quinine (QUALAQUIN)

People who use quinine (QUALAQUIN) for nighttime leg cramps may be at risk of seri­ous side effects, including bleeding, according to the Food and Drug Administration (FDA).

The agency’s July 8, 2010, an­nouncement came in response to continuing reports of serious adverse drug reactions in patients using the drug for this purpose. The agency is instituting a risk-management plan to warn against use of the drug for “off-label” purposes.

An off-label use is one that is not approved by the FDA. The use of quinine for nighttime leg cramps is an off-label use because quinine is not approved to treat nighttime leg cramps; in fact, the drug is only ap­proved by the FDA for the treatment of malaria caused by the parasite Plasmodium falciparum. According to the FDA, the majority of quinine use in the U.S. is for the treatment or prevention of nocturnal leg cramps — not for malaria. Although doctors may prescribe an approved drug for a purpose other than its FDA-approved purpose, manufacturers are prohib­ited from promoting a drug for an off-label use.

Quinine use can lead to blood-related reactions, including serious internal or external bleeding due to a severe lowering of platelets in the blood and a condition known as hemolytic-uremic syndrome/throm­botic thrombocytopenic purpura, which in some cases may result in permanent kidney damage. In some patients, these adverse reactions have resulted in hospitalization and death.

The FDA’s risk-management plan, called a Risk Evaluation and Mitigation Strategy (REMS), requires pharmacists to give patients a medica­tion guide that explains what quinine is approved for, as well as potential side effects. In addition, the REMS requires the manufacturer to issue a “Dear Health Care Provider” letter warning of the risk of serious and life-threatening hematologic (blood-related) reactions.

An examination of the adverse drug reaction reports submitted to the FDA from April 2005 to Oct. 1, 2008, found 38 cases of serious adverse reactions associated with the use of quinine in the U.S. Two-thirds (25) of these patients took quinine to prevent or treat leg cramps or Restless Leg Syndrome. Only one patient was taking quinine for the treatment of malaria.

Among the 38 reports, there were 24 blood-related reactions, four cardiovascular events and 10 mis­cellaneous adverse events such as gastrointestinal symptoms, hearing loss, rash, electrolyte imbalance and drug interaction. Two deaths were reported; both were associated with blood reactions.

The Health Research Group and quinine

Public Citizen’s Health Research Group petitioned the FDA to ban the over-the-counter sale of quinine for leg cramps in 1988 and to ban prescription use of quinine for leg cramps in 1994.

FDA black-box warning

Quinine must display a black-box warning in its professional product label about an increased risk of seri­ous and life-threatening adverse drug reactions.

A boxed warning is the strongest type of safety warning that the FDA can require in a drug’s professional product label or package insert and is reserved for products that can cause serious harm or death to patients.

What You Can Do

You should not use QUALAQUIN or any other quinine-containing product for nighttime leg cramps or any purpose other than the treatment of malaria.

Quinine must be dispensed with an FDA-approved medication guide written specifically for consumers in nontechnical language. Read the medication guide for quinine, avail­able on the FDA’s website or from your local pharmacist.

You should contact your health care provider immediately if you experience any of the following:

• Easy bruising
• Severe nose bleeding
• Blood in your urine or stool
• Bleeding gums
• Unusual purple, brown or red spots on your skin

Consumers may report serious adverse events with quinine or other product-quality problems to the FDA’s MedWatch Adverse Event Reporting program either online or by mail, fax or phone.

Online: https://www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm
Regular Mail: Use postage-paid FDA form 3500 and mail to Med­Watch, 5600 Fishers Lane, Rockville, MD 20852-9787
Fax: (800) FDA-0178
Phone: (800) FDA-1088