Qualaquin is a drug used to treat malaria caused by mosquito bites. It works by killing malaria parasites residing in red blood cells. It is an antimalarial and may be used in combination with other drugs. The FDA has warned that it should not be used to treat leg cramps, as it may cause adverse side effects that outweigh any potential benefits gained from using the drug. It has shown to be effective in regions where resistance to chloroquine is documented. Qualaquin should not be used in the prevention of malaria.


Qualaquin may cause the following adverse reactions: prolonged QT interval, G6PD deficiency, hypersensitivity reactions, or serious cardiac arrhythemias. It may also cause severe bleeding due to a lowering of blood platelets (thrombocytopenia).  These effects may be life threating, requiring hospitalization and serious medical intervention. Use of qualaquin for leg cramps has also led to serious blood disorders.


The majority of patients who took quinine, the active drug found in Qualaquin, were using it for the treatment of leg cramps, according to an FDA study conducted from April 2005 to 2008. 24 of 38 recorded cases were of blood related illnesses, with victims hospitalized in 18 of the cases. 2 cases resulted in death of the patient. This has led qualaquin to be a controversial drug with increasing lawsuits on the rise. Hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura, conditions that can cause permanent kidney damage,   led to the rise of kidney damage lawsuits.