Postural hypotension: adrenergic responsivity and levodopa therapy.

Four subjects with orthostatic hypotension were given intravenous infusions of methoxamine and isoproterenol. Methoxamine caused an elevation in systolic blood pressure. Isoproterenol resulted in a fall in blood pressure in three of the subjects. The heart rate decreased with methoxamine, but increased with isoproterenol. The responsivity in orthostatic hypotension was compatible with denervation supersensitivity. These effects were compared with the responsivity to methoxamine and isoproterenol of five labile hypertensives. Two patients with severe orthostatic hypotension were treated with regimens including levodopa. Levodopa alone would further aggravate postural hypotension. But in one subject given levodopa, ephedrine, and fludrocortisone and in the other managed on levodopa, tranylcypromine, and fludrocortisone, symptomatic orthostatic hypotension was successfully eliminated. These results support the usefulness of levodopa, in combination with adrenergic agents, as a therapeutic measure for advanced forms of orthostatic hypotension.