Haemodynamic studies on the antihypertensive effect of guancydine

Summary

Guancydine, a new antihypertensive agent, was given orally in divided doses up to 1000 mg a day, to five male in-patients with severe arterial hypertension. Haemodynamic parameters were determined at rest and during standardized exercise before and after seven to fourteen days of treatment. In the second study significant reductions in the systemic vascular resistance were found which paralleled the lower brachial artery blood pressure. The circulation was hyperkinetic and the cardiac output was increased. Also, during exercise the blood pressure remained much lower despite a relatively greater cardiac output, resulting in significantly lower levels of vascular resistance. Sodium retention occurred in one patient, and central nervous system symptoms were reported by two men during treatment with guancydine. However, these findings should encourage further studies to establish the clinical usefulness of guancydine, as they suggest it to have a peripheral site of action, perhaps directly on blood vessel walls.