Antiplatelet effects of oral diltiazem, propranolol, and their combination.
1. The antiplatelet effects of a single oral dose of the calcium entry blocker diltiazem (60 mg), the beta-adrenoceptor blocker propranolol (40 mg), and their combination were studied in five healthy subjects. 2. Platelet aggregation and ATP release induced by adrenaline and ADP and ADP induced platelet thromboxane A2 generation were significantly inhibited (P less than 0.05) by either diltiazem or propranolol, although propranolol tended to have greater inhibitory effects on platelet function than diltiazem that did not reach statistical significance. 3. Combination therapy resulted in additive antiplatelet effects that were significantly (P less than 0.05) greater than either drug alone. 4. These data indicate that combined administration of a calcium entry blocker and a beta-adrenoceptor blocker results in additive inhibitory effects on platelet function. These effects may mediate part of the therapeutic efficacy of combination therapy in patients with coronary artery disease.
Department of Internal Medicine, University of Arizona College of Medicine, Tucson.
M E
ME
Ring
J J
JJ
Corrigan
P E
PE
Fenster
D000244:Adenosine Diphosphate / Q000097:blood; D000255:Adenosine Triphosphate / Q000097:blood; D000328:Adult; D004110:Diltiazem / Q000494:pharmacology*; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D008297:Male; D010975:Platelet Aggregation Inhibitors; D011433:Propranolol / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000097:blood
D010975:Platelet Aggregation Inhibitors; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D011433:Propranolol; D004110:Diltiazem; D004837:Epinephrine