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FDA Drug Safety Podcast for Healthcare Professionals: New risk management plan and patient Medication Guide for Qualaquin

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Welcome, my name is Chris Jones, a pharmacist in the Division of Drug Information. Today, I am updating you on a newly approved risk management plan to warn against using Qualaquin "off-label" for night time leg cramps.

Qualaquin is ONLY FDA-approved for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum, a rare infection in the United States, seen primarily in travelers returning from malaria-endemic areas. However, the majority of Qualaquin's use in the United States is for the treatment or prevention of night time leg cramps, a use NOT approved by FDA.

Qualaquin use may result in serious and life-threatening hematological reactions, including serious bleeding due to thrombocytopenia, and hemolytic-uremic syndrome/ thrombotic thrombocytopenic purpura which in some cases may result in permanent kidney damage. In some patients, adverse reactions result in hospitalization and death.

A review of reports submitted to FDA's Adverse Event Reporting System from April 2005 to October 1, 2008, found 38 U.S. cases of serious adverse events associated with quinine, the active drug in Qualaquin. 25 of the 38 patients took quinine to prevent or treat leg cramps or Restless Leg Syndrome; only 1 patient was taking quinine for the treatment of malaria. 

Among the 38 reports, there were 24 hematologic events, four cardiovascular events, and 10 miscellaneous adverse events such as gastrointestinal symptoms, hearing loss, rash, electrolyte imbalance, and drug interaction. Of the 24 patients with reported hematologic adverse events:

  • The median time-to-onset of adverse events after starting quinine was 13.5 days.
  • Twenty-one patients had a diagnosis of thrombocytopenia and required hospitalization. Of these, 18 reports provided data on platelet count:
    • median platelet count: 4500 cells/μL
    • case range: 1000 - 83,000 cells/μL; (compared to a normal range: 150,000 - 450,000 cells/μL).
  • Twelve reports noted that patients had mucosal bleeding (gingival, gastrointestinal, or epistaxis), hemoptysis, petechiae, or ecchymosis.
  • Four cases of thrombocytopenia were further classified 2 thrombotic thrombocytopenic purpura (TTP) and 2 idiopathic thrombocytopenic purpura (ITP).
  • Two deaths were reported, one death due to TTP and one due to hemolysis.
  • Most of the patients with thrombocytopenia recovered when quinine was discontinued and other therapeutic interventions were initiated.

The risk management plan, called a Risk Evaluation and Mitigation Strategy (REMS), requires that patients be given a Medication Guide explaining what this medication is and is not approved for, as well as the potential side effects of this drug. In addition, the REMS requires that the manufacturer issue a Dear Health Care Provider Letter warning of the risk of serious and life-threatening hematologic reactions.

Healthcare Professionals should:

  1. Know that Qualaquin is only approved for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum.
  2. Understand that Qualaquin is NOT approved for the treatment or prevention of night time leg cramps. Prescribing Qualaquin for this condition exposes patients to risk for serious adverse events.
  3. Discuss with patients the warning signs of thrombocytopenia such as easy bruising, severe nose bleeds, blood in the urine or stool, bleeding gums, and the appearance of unusual purple, brown, or red spots on the skin.
  4. Encourage patients to read the Medication Guide given to them at the pharmacy before starting Qualaquin and each time they get a refill.
  5. Report any adverse events with Qualaquin to FDA's MedWatch program at www.fda.gov/medwatch.

Thank you for listening. The FDA is committed to keeping healthcare professionals informed of the latest safety information. If you have questions about this safety communication, you can reach the Division of Drug Information at the following email address: druginfo@fda.hhs.gov.

 

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