[Effects of nitrates and beta-blockers on platelet aggregation in patients with coronary heart disease]

Abstract

Our study aimed at evaluating an effect of the selected nitrates and beta adrenoceptor blockers on platelet aggregation in patients (pts) with coronary artery disease (CAD). The study included 168 male patients (M), aged between 33 and 72 years (mean age 51 +/- 7). 61 M given isosorbide dinitrate were divided into three groups: in the group I and II an effect of the drug on the platelet aggregation following a single 10 mg (I) and 20 mg (II) dose has been evaluated; in group III an effect of the drug after a two-week treatment has been evaluated. 14 male patients (group IV) were given 5-mononitrate 40 mg daily for two weeks. 85 male patients, treated with propranolol have also been divided into three groups. In group V and group VII an effect of propranolol on platelet aggregation following a single dose of 40 mg and 80 mg has been evaluated respectively. In the group VII an outcome of a two-week propranolol therapy has been assessed. Eleven patients (group VIII) received nadolol in a dose of 40-80 mg daily for two weeks. Platelet aggregation induced by adenosine diphosphate (ADP) in concentration of 1 mM/ml and 5 mM/ml (groups I, II, III, V, VI, VII) and only of 1 microM/ml (groups IV, VIII) was evaluated with Born's method. In patients with CAD only isosorbide dinitrate inhibits platelet aggregation. This effect has been noted following a single dose as well as a two-week treatment. Other drugs (5-mononitrate, propranolol, nadolol) transiently increase platelet aggregation, but became either ineffective after two-week therapy (5-mononitrate, nadolol) or increase (propranolol) platelet aggregation. Tendency to inhibit (sorbonit) or to increase (propranolol) platelet aggregation has been more pronounced with higher concentration of aggregating factor.