Quinine and Warfarin

Publication Date: 
Tue, 07/01/2014
By: Alere Staff

Quinine, known as an antimalarial medication, is a compound that is used to kill the organisms that cause malaria.1 This compound is found in anti-malarial drugs and tonic water. For treatment of malaria, quinine may be used alone or with other medications. Quinine is not used to prevent malaria.1  

In the past, quinine was used off-label in the United States for leg cramping. According to the National Institute of Health, the drug quinine should not be used to treat or prevent nighttime leg cramps.1

In 2007, the U.S. Food and Drug Administration (FDA) instructed manufacturers to stop “marketing unapproved drug products containing quinine" because of serious safety concerns. The FDA received 665 reports of serious adverse events associated with quinine use since 1969, including 93 deaths. Among the side effects of quinine are cardiac arrhythmias, thrombocytopenia and severe hypersensitivity reactions”.2 Quinine sulfate (brand name Qualaquin® medication), is manufactured by Mutual Pharmaceutical Company, and recommended only for treatment of malaria.3

Historically, quinine has been used from the dried ground bark of the cinchona plant to treat malaria, fever, and indigestion. A typical cinchona bark contains about 16% of quinoline alkaloids consisting mainly of quinine, quinidine, cinchonine, and cinchonidine. Quinine is used to flavor beverages such as tonic water. Tonic water contains about 15 mg of quinine per bottle.4

Quinine may cause the patients blood platelet levels to drop, putting them at a risk for bleeding. If you are taking warfarin, this could cause serious bleeding problems.Talk to your doctor or pharmacist before starting or stopping any new medications or food/drink like tonic water while you are taking warfarin.

  1. Medline Plus. Quinine. http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682322.html. Updated February 1, 2011. Accessed June 9, 2014.
  2. U.S. Food and Drug Administration. Quinine products. http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm150746.htm. AccessedJune 9, 2014.
  3. MutualPharmaceutical Company, Inc. MedicationGuide for QUALAQUIN (quinine sulfate) Capsules. [PackageInsert]. Philadelphia, PA: April, 2013.
  4. Aster RH. Quinine sensitivity: a newcauseof the hemolytic uremic syndrome[letter]