Celiprolol hydrochloride is a cardioselective beta 1-adrenergic antagonist with partial agonist activity. The studies discussed were designed to assess celiprolol's pharmacokinetic disposition, its efficacy versus placebo and other beta blockers, its relative safety profile, and its therapeutic ratio in the elderly population. The results of a postmarketing surveillance study are also presented. Pharmacokinetic results indicate good dose-related bioavailability in the elderly, no accumulation on multiple dosing, and pharmacokinetics equivalent to those in a younger age group. Celiprolol effectively lowers blood pressure in elderly patients with mild to moderate hypertension, resulting in reductions of 12-15 mmHg and 8-11 mmHg in systolic and diastolic blood pressures, respectively. A clinically insignificant reduction in resting pulse rate is observed with celiprolol treatment. Its adverse experience profile is equivalent to that of placebo, and the incidence of beta-blocker-associated side effects is lower compared with that of atenolol and propranolol. Celiprolol also effectively controlled hypertension in the elderly in the postmarking surveillance study. Collectively, the results of these studies demonstrate that the pharmacokinetics and efficacy of celiprolol in the treatment of mild to moderate hypertension are equivalent in younger and older populations, and that the therapeutic ratio (i.e., efficacy/safety) of celiprolol is superior to that of atenolol and propranolol in the elderly.