Pharmacokinetics and hemodynamic and diuretic/natriuretic effects of felodipine administered as an extended-release...

In this study the pharmacokinetics, and the hemodynamic and diuretic/natriuretic effects of three different doses of felodipine ER-10, 20, and 40 mg--were evaluated in healthy subjects. There was a linear correlation between the dose of felodipine, Cmax, and AUC24, showing that the absorption was linearly related to the dose. The diastolic blood pressure was reduced by 15-20% after the two highest doses. The maximal blood-pressure lowering effect was seen 4 hours after drug intake, and a small reduction in diastolic blood pressure was still present after 24 hours. This was, however, not statistically significant but was related to a sustained effective plasma concentration of the drug (6 nmol/l). Systolic blood pressure was not affected. The two highest doses of felodipine ER produced a significant increase in heart rate 2 and 6 hours after the dose, compared with placebo. There was also a significant decrease in forearm vascular resistance after the 20- and 40-mg doses. Both diuresis and natriuresis were significantly increased by about 100% each during the first 4 hours after the 20-mg dose. Following the 40-mg dose, diuresis and natriuresis were lower than after 20 mg and were not significantly different from placebo.