Effect of felodipine and metoprolol on muscle and skin arteries in hypertensive patients.

The antihypertensive and vasodilator effects of felodipine, a new calcium antagonist of the dihydropyridine group, were examined in 15 patients with moderate to severe hypertension. Flow was measured simultaneously at the calf and finger using a venous occlusion ECG-triggered plethysmograph. Measurements were made at rest, during handgrip and during reactive hyperaemia. Felodipine (12.5 mg, orally) was given after placebo treatment and after 3 weeks' treatment with metoprolol. It was also given for 3 weeks in combination with metoprolol. Felodipine caused a significant decrease in blood pressure which was similar in the supine, sitting and standing positions without causing any orthostatic reaction. The antihypertensive effect was accompanied by an increase in heart rate, dilatation of calf arteries and, to a lesser degree, dilatation of finger arteries. However, the degree of vasodilatation diminished with long term treatment. Metoprolol prevented the increase in heart rate but not vasodilatation. Felodipine decreased the potential for further dilatation in certain situations, as shown during reactive hyperaemia, although vasoconstrictor responses during the handgrip test remained unimpaired.