The pharmacokinetics of quinine in patients with hepatitis.

The pharmacokinetics of quinine were studied in six patients with hepatitis B infection (during acute and convalescent periods) and six healthy subjects. A single 10 mg kg-1 dose of quinine was given intravenously over 2 h. Pharmacokinetic parameters of quinine during the acute phase of the infection were not different from those during the recovery phase. However, when compared with those obtained from healthy subjects, significant changes were found. The terminal elimination half-life was prolonged (17 and 15 vs 10 h) and clearance was lower (2.9 and 2.3 vs 3.5 ml min-1 kg-1). Unbound quinine concentration in plasma at 2 h was approximately 10% of the total concentration in all subjects in the three study groups. A prolonged QTc interval (< 25%) was observed in all groups. The present data suggest that current dosage regimens of quinine used in the treatment of falciparum malaria may not be suitable for malaria patients with acute hepatitis or those who have had hepatitis within the past 3 months.