Time-dependent effects of metoprolol in patients with coronary heart disease and grade II–III angina pectoris

BACKGROUND: This study focused on the topical problem of studying the time-dependent effects of the cardioselective β-adrenergic receptor blocking agent metoprolol in patients with coronary heart disease (CHD) and grade II–III angina pectoris.

AIM: This study aimed to analyze the effect of metoprolol when used at different times of the day based on the concept of chronopharmacology, which is based on the variability of adrenoreceptor sensitivity depending on the day-night cycle.

MATERIALS AND METHODS: Acute clinical and pharmacological tests were performed in 20 patients with CHD and grade II–III angina pectoris to determine the time-dependent effects of metoprolol. All patients underwent a study of the parameters of central and peripheral hemodynamics, as well as electrocardiography and echocardiography. The study results were subjected to statistical analysis.

RESULTS: Metoprolol at 100 mg at different hours of the day causes a persistent negative chrono- and inotropic, hypotensive effect. The clinical and pharmacological test results registered the listed effects with favorable shifts in the first instance when taking the drug in the morning and midday hours. Circadian rhythms of sensitivity of several indicators of the cardiovascular system to metoprolol have been established.

CONCLUSIONS: The study results on the time-dependent hemodynamic effects of metoprolol using acute pharmacological tests enabled to establish the presence of a circadian organization of several hemodynamic parameters with an acrophase of sensitivity to metoprolol at 15:00 and 14:00 h.