Approved Use

• As noted in quinine sulfate's prescribing information, the FDA has approved the medication "only for treatment of uncomplicated Plasmodium falciparum malaria." The statement of indications goes on to specify that quinine sulfate is not indicated for treating any other disease, infection or condition. When taking the medication to treat malaria, patients must take two capsules three times a day for seven days.
  
  

Off-Label Uses

• Some physicians prescribe quinine sulfate off-label for treating at least half a dozen health problems besides uncomplicated malaria. As noted in a safety summary FDA issued on June 29, 2009, some patients take quinine sulfate when they suffer from nocturnal leg cramps, restless leg syndrome, diarrhea with cramping, muscle cramps and neuropathy. However, FDA allows doctors to prescribe any medication for any problem for which a doctor believes the medication can treat.
  
  

Side Effects

• Quinine sulfate produces a cluster of usually reversible side effects in close to 100 percent of people who take the medication, according to the drug's prescribing information. Mild problems for patients include nausea, ringing or buzzing in the ears, blurred eyesight, headaches, skin flushing and sweating. These problem can be as severe as vomiting, deafness, blindness and irregular heartbeat for other patients. Less-common side effects patients have experienced from quinine sulfate have included chills, overall weakness, lowered blood cell counts, internal bleeding, mental disturbances, rashes, breathing difficulties, muscle pain, low blood sugar and hypotension.
  
  

Contraindications

• Patient with abnormally slow heartbeats, progressive weakening of their muscles or the condition known as optic neuritis cannot take quinine sulfate. Optic neuritis involves swelling of the optic nerve, temporary vision loss and pain at the back of the eye. Also, while taking quinine sulfate with other medications presents few dangers, quinine sulfate's prescribing information includes a long list of drugs that will cancel out any benefits from one or both medications when patients take them at the same time.
  
  

FDA Warnings

• The FDA ordered all unapproved quinine sulfate products---particularly nonprescription products---off the U.S. market in December 2006, citing both a lack of evidence that the medication was effective for treating or preventing any health problems other than malaria and the high risk of serious side effects. The agency found it necessary to reiterate these messages in June 2009, writing in a safety alert that since 2005, when it approved Qualaquin, it had received 38 reports of life-threatening side effects among people who took quinine sulfate for nocturnal leg cramps or other conditions. Of these patients, five died. This led the FDA to write that it, "encourages healthcare professionals to: (1) Only prescribe quinine sulfate (Qualaquin) for the FDA-approved indication of treatment of uncomplicated P. falciparum malaria; (2) seek alternative therapies to treat nocturnal leg cramps or other musculoskeletal disorders, as quinine is not approved for these conditions."