Treatment of neurogenic orthostatic hypotension with a monoamine oxidase inhibitor and tyramine.

The clinical response of treatment with a chemical preparation of tyramine and tranylcypromine, a monoamine oxidase inhibitor, is described in six patients wit neurogenic orthostatic hypotension. Previous therapy with fluorocortisone, ephedrine, elastic garments, postural training and, in one patient, an anti-G suit was unsuccessful. Oral and intravenous tyramine produced no pressor response. However, after treatment with tranylcypromine five of the patients when supine showed a marked rise of blood pressure to intravenous tyramine which was sustained for over two hours when they stood up. Tyramine given orally with tranylcypromine produced a moderate rise of blood pressure in the supine position which was sustained for over 3-4 hours in the erect position enabling patients to walk about without symptoms of orthostatic hypotension. Measurement of circulating adrenaline and noradrenaline during therapy suggested that the pressor response was due to release of noradrenaline. Three patients have had marked improvement for four, fifteen and twenty-four months respectively. In a further patient, therapy has been successful in treating his orthostatic hypotension although his mobility has been restricted due to cerebellar ataxia. One patient developed a confusional state during treatment and the therapy was stopped. The only patient in whom the drugs produced no pressor response had orthostatic hypotension with evidence of adrenergic innervation of blood vessels, but failure of noradrenaline release. It is suggested that the pressor response to a monoamine oxidase inhibitor and tyramine should be examined in patients to a monoamine oxidase inhibitor and tyramine should be examined in patients with neurogenic orthostatic hypotension in whom conventional therapy is unsatisfactory and those who respond should receive a trial of this treatment.