Clinical dose-response studies with guanfacine (BS 100-141), a new antihypertensive agent.

1. Blood pressure, pulse rate, salivary flow and the degree of sedation were recorded at intervals following oral administration of single doses of guanfacine, a clonidine-like agent, to hypertensive patients. 2. Between 2 and 10 h after administration of guanfacine (3 mg or 5 mg), there were dose-related decrease in lying and standing blood pressure, together with significant reductions in pulse rate and salivary flow. 3. It is concluded that guanfacine lowers blood pressure in hypertensive patients and is probably suitable for twice daily administration, but produces xerostomia and sedation.