Quinine is used alone or with other medications to treat malaria (a serious or life-threatening illness that is spread by mosquitos in certain parts of the world). Quinine should not be used to prevent malaria or to prevent or treat nighttime leg cramps. Quinine is in a class of medications called antimalarials. It works by killing the organisms that cause malaria.

ISSUE: Due to continued reports of serious side effects in patients using quinine (Qualaquin) "off-label" for night time leg cramps, FDA has approved a risk management plan to warn against the use of this drug for such unapproved uses. Quinine should not be used for night time leg cramps. Quinine 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.