Influence of Acetazolamide on Cerebral Blood Flow

Abstract

Carbonic anhydrase inhibitors have been used in clinical medicine as diuretics,^1-3 as anticonvulsants,^4,5 to reduce intraocular tension,^6,7 to lower intracranial pressure,^8,9 and in the treatment of respiratory insufficiency.^10,11 In the course of investigation of the effects of acetazolamide in hepatic encephalopathy, Posner and Plum¹² observed without comment a considerable increase in rate of cerebral blood flow after intravenous administration of 1 to 2 gm. of acetazolamide. Such a cerebral circulatory change had previously been considered to account for the brief elevation of cerebrospinal fluid pressure after intravenous acetazolamide.^9,13 In view of these findings, we felt that the usefulness of carbonic anhydrase inhibitors might be extended to the management of patients with intermittent cerebral vascular insufficiency. In this preliminary report, observations of the quantitative cerebral hemodynamic effects of intravenous acetazolamide are presented. In several subjects, the effects of inhalation of 5% CO₂ were