The pharmacologic data obtained from animal experiments and pharmacokinetics of guanfacine in man are reviewed. Guanfacine exhibits a high selectivity for alpha 2-adrenoceptors with predominantly central action, but peripheral presynaptic alpha 2-adrenoceptor stimulation may also contribute to the antihypertensive effect. Guanfacine has the advantage over other centrally acting antihypertensives of being less sedative and causing no rebound hypertension after discontinuation of treatment. The latter is mainly due to its pharmacokinetic properties. Human pharmacokinetic studies in patients with renal failure indicate that due to an increase in metabolic clearance and increase in non-renal elimination of the drug guanfacine may be administered to elderly patients and patients with renal impairment without dosage adjustment.