Effect of felodipine-ER on blood pressure, platelet function, and rheological properties in hypertension.

Twenty patients with mild to moderate hypertension took part in this study consisting of a two-week placebo treatment period, followed by treatment with an extended-release calcium channel blocker, felodipine-ER (5 to 20 mg once daily) for 12 weeks. The study evaluated the effects of felodipine-ER on blood pressure, platelet function and rheological properties in hypertension. Felodipine-ER significantly reduced systolic and diastolic blood pressure without changing heart rate. There was a significant decrease in adenosine diphosphate-induced platelet aggregation and platelet intracellular calcium concentration, but no significant change in plasma thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and platelet cyclic 3'5'-adenosine monophosphate concentrations. Adverse effects on biochemical and rheological properties were not found. In conclusion, felodipine-ER is an effective and metabolically safe antihypertensive drug. It reduces platelet aggregability and intracellular free calcium concentration without altering the production of TXB2 and 6-keto-PGF1 alpha.