Initial clinical experience with a new peripheral vasodilator, PR-G-138-Cl, in hypertensive patients.

PR-G-138-C1, a new antihypertensive agent with vasodilating properties, was studied in ten patients with moderate to severe hypertension. The patients were admitted to a metabolic ward and followed on a 2 gm salt diet. Placebo was given daily until blood pressure and weight were stabilized. A dose titration was then started with increasing single daily doses of 3, 5, 8, and 10 mg of PR-G-138-C1 orally. The dose at which the mean arterial pressure was reduced by 15 mm Hg was continued for a total of seven days. PR-G-138-C1 lowered sitting mean arterial pressures significantly in all subjects (133.8+/-15.1 leads to 116.0+/-12.4 mm Hg, p less than 0.001). The antihypertensive effect was first noted 30 minutes following drug administration and persisted for as long as six hours with a peak effect at one hour. All patients had a significant increase in sitting pulse rate (80.4+/-9.11 leads to 90.0+/-6.91/min, p less than 0.002). Blood pressure reduction and increase in pulse rate were dose related. The most common side effects noted were headaches in eight out of ten patients and postural dizziness in seven out of ten patients. There were no signs of fluid retention (weight gain or edema). Electrocardiogram and other laboratory parameters remained essentially unchanged.