A new trend in the therapy of orthostatic arterial hypotension: prevention by propranolol or metoclopramide of the excessive adrenaline release of brainstem infarct patients with postural hypotension.

The catecholamine (CA) response to upright posture was studied in 30 brainstem infarct patients with orthostatic arterial hypotension; the investigation was made before and after 10 days propranolol therapy (in 15 cases) and before and after 10 days metoclopramide therapy (in other 15 cases). Before treatment almost all patients responded to posture by a rise in adrenaline (A) excretion and by a depression in noradrenaline (NA) excretion. Propranolol therapy prevented the excessive A release produced by standing and normalized their NA response to posture. Metoclopramide administration also prevented the post-orthostatic A discharge but had no significant influence on NA response to posture. Both drugs exerted a favourable influence on postural hypotension of investigated patients. As post-orthostatic A discharge observed in patients with postural hypotension is involved in the pathogeny of this syndrome and both metoclopramide and propranolol are able to correct this disorder one may maintain that the clinical favourable results obtained with these drugs are ascribable at least partly to their blocking effect on A release.