Interactions between tenormin(atenolol) and Atazanavir (atazanavir)
atenolol and atazanavir (Major Drug-Drug)
MONITOR CLOSELY: Atazanavir has been shown to prolong the PR interval of the electrocardiogram in some patients. Theoretically, coadministration with other agents that prolong the PR interval (e.g., beta blockers, digoxin, verapamil) may result in elevated risk of conduction disturbances and atrioventricular block. In a pharmacokinetic study, no substantial additive effect on the PR interval was observed during coadministration of atazanavir (400 mg once a day) and atenolol (50 mg once a day). However, an additive effect cannot be excluded because data are limited and atazanavir has not been studied in combination with other agents that prolong the PR interval.
MANAGEMENT: Caution is advised if atazanavir is used concomitantly with other agents that prolong the PR interval, particularly those that are metabolized by CYP450 3A4 (e.g., verapamil), since atazanavir is an inhibitor of that isoenzyme.
