The U.S. Food and Drug Administration has banned the sale of all non-approved brands of quinine because of the risk of serious side effects or death. As of December 2006, Qualaquin is the only brand of quinine that is approved by the FDA.
Quinine can cause serious or life-threatening side effects, and is approved for use only in treating malaria. Some people have used quinine to treat leg cramps, but this is not an FDA-approved use.
Do not use quinine to treat any medical condition if your doctor did not prescribe quinine for that condition. Do not purchase quinine on the Internet or from vendors outside of the United States. Using this medication improperly or without the advice of a doctor can result in serious side effects or death.
Do not use this medication if you have ever had an allergic reaction to quinine or similar medicines such as mefloquine (Lariam) or quinidine (Cardioquin, Quinidex, Quinaglute).
You should not take quinine if you have a history of "Long QT syndrome”, or if you have glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, myasthenia gravis, or optic neuritis (inflammation of the nerves in your eyes).
Call your doctor at once if you have a weak pulse, if you faint or collapse, if you have fever, confusion, pale or yellowed skin, dark colored urine, hearing or vision loss, purple spots under your skin, a blistering or peeling skin rash, or if you urinate less than usual or not at all.
No medication is 100% effective in treating malaria. For best results, keep using the medication as directed. Talk with your doctor if you have fever, vomiting, or diarrhea during your treatment.