The relationship between debrisoquine oxidation phenotype and the pharmacokinetics and pharmacodynamics of propranolol.

The pharmacokinetics and pharmacodynamics of propranolol (80 mg by mouth) were studied in seven extensive and four poor metabolisers of debrisoquine. Evidence for impairment of the 4'-hydroxylation of propranolol was found in poor metabolisers. However, no significant difference was detected in the oral clearance of unchanged drug between the two groups of debrisoquine oxidation phenotypes. Poor metabolisers of debrisoquine did not experience more intense or more prolonged beta-adrenoceptor blockade than extensive metabolisers of debrisoquine.