Absorption of quinine occurs mainly from the upper small intestine. Following administration of a single oral dose, peak serum concentrations of quinine generally occur within 1-3 hours. Plasma concentrations of quinine are higher and the plasma half-life of the drug may be longer in patients with malaria than in healthy individuals or patients convalescing from malaria, apparently because malaria can cause impaired hepatic function which results in a decrease in total body clearance of quinine and a decrease in the volume of distribution of the drug. Quinine is widely distributed in body tissues. Quinine readily crosses the placenta and is distributed into milk.
Quinine sulfate is extensively metabolized, mainly in the liver.
Because quinine is reabsorbed when the urine is alkaline, renal excretion of the drug is twice as rapid when the urine is acidic than when it is alkaline. Quinine is removed by hemodialysis or charcoal hemoperfusion, but the drug is not effectively removed by peritoneal dialysis. The combination of quinine sulfate and clindamycin may be useful in the treatment of cryptosporidiosis . Other Major Uses Treatment of malaria, nocturnal recumbent leg muscle cramps and Babesia microti infections. Other adverse effects include hypoglycemia, and renal failure.