Pressor amines and monoamine-oxidase inhibitors for treatment of postural hypotension in autonomic failure. Limitations and hazards.

The short-term effects of pressor amines were investigated in four patients with postural hypotension caused by autonomic failure. In supine patients p-tyramine alone or with a monoamine-oxidase inhibitor produced pronounced supine hypertension without abolishing the symptoms associated with a postural fall in blood-pressure. Phenylephrine or ephedrine maintained a normal blood-pressure on standing but caused supine hypertension. Thus the effects of p-tyramine with or without a monoamine-oxidase inhibitor were unpredictable and did not include relief of postural hypotension. Phenylephrine or ephedrine had some beneficial effect, but since all these drugs influence standing pressure only at the expense of pronounced supine hypertension, alternative therapy must be sought.