Quinine is readily and completely absorbed from the small
intestine when given orally. Quinine is a potent local irritant and
is not generally administered by either intramuscular or subcutaneous
injection. Peak plasma concentration is reached within one to three
hours following a single oral dose. Therapeutic doses of 1 g/day of
quinine for several days result in an average plasma quinine
concentration of approximately 7 µg/ml with a plasma half-life of
about 12 hours. Approximately 70% of plasma quinine is bound to
proteins. Quinine is extensively metabolized in the liver with less
than 5% excreted unaltered in the urine (Webster, 1985; White, 1987).
The pharmacokinetics of quinine are variable (clearance 0.9-1.8
ml/kg/min., half-life 8.4-18.2 hours). Quinine readily crosses the
placenta (Webster, 1985; White, 1987).