PHARMACOKINETIC INTERACTION OF SINGLE DOSES OF QUININE AND CARBAMAZEPINE, PHENOBARBITONE AND PHENYTOIN IN HEALTHY-VOLUNTEERS

Effects of single doses of quinine on plasma and urine concentrations of carbamazepine, phenobarbitone and phenytoin were studied in healthy volunteers. Quinine (600mg, p.o.) markedly augmented the peak plasma concentrations and area under the curve (AUC [0-24]) values of carbamazepine (200mg, p.o.) and phenobarbitone (120mg, p.o.) but did not affect those of phenytoin (200mg, p.o.). Mean urinary recoveries of carbamazepine, phenobarbitone and phenytoin over 24 hours also profoundly increased with concomitant administration of quinine. These results indicate possible interaction between quinine and carbamazepine or phenobarbitone.