title: Acute action of guanfacine on peripheral circulation in hypertensive patients: measurements of arterial flow of the calf and of the forefoot, of venous capacity of the calf, of the blood pressure and of the heart rate.
abstract: 1. The acute action of an intravenous infusion (5 min) of guanfacine in doses of 0.01, 0.02 and 0.04 mg/kg on peripheral circulation was studied in five hypoertensive patients and compared with a placebo in a randomized study. The observations were combined for 2 h after drug administration. 2. Two phases of drug action were seen during and immediately after the administration of guanfacine; a dose-dependent decrease in blood flow mainly of the forefoot but also in the calf was combined with an increase in systolic and diastolic blood pressures and a decrease in heart rate. Peripheral resistance was increased in this phase. Later, an increase in blood flow to the foot combined with a tendency towards a decrease in blood pressure were observed. 3. These preliminary results show that this second phase of action of guanfacine is dependent on the dose given.
mesh_terms: D000328:Adult; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001158:Arteries; D001775:Blood Circulation / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D016316:Guanfacine; D006146:Guanidines / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D010648:Phenylacetates / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D014680:Veins / Q000187:drug effects
chemical_list: D000959:Antihypertensive Agents; D006146:Guanidines; D010648:Phenylacetates; D016316:Guanfacine