Interaction of Metoprolol, Propranolol and Atenolol with Cimetidine

1. Pharmacokinetics of metoprolol, propranolol and atenolol were investigated in six healthy volunteers after 7 days of oral monotherapy with these drugs and after 7 days concurrent administration, with each of these β-adrenoceptor antagonists with cimetidine.

2. Cimetidine did not interact with atenolol, whereas mean peak plasma concentrations of metoprolol were increased by 70%, and those of propranolol by 95% with concurrent administration of cimetidine (P < 0.05).

3. The area under the plasma concentration-time curve for propranolol and metoprolol was similarly increased (P < 0.05).