Intravenous diazoxide produced an immediate marked hypotension in both mild and severe hypertensive patients. Depression of vasomotor reflexes, tested by the Valsalva overshoot, and of pressor responsiveness to noradrenaline was found only in the group of mild hypertensives. Decreased pressor reactivity to noradrenaline was not due to a nonspecific vascular effect of diazoxide, because pressor responsiveness to angiotensin was simultaneously increased. Renal tubular reabsorption of sodium and water was increased shortly after injection of diazoxide, and there was also a significant retention of potassium. Correlation studies suggest that interference with vasomotor reflexes, and with vascular responsiveness to the sympathetic transmitter, can account only in part for the hypotensive action of diazoxide. The possible rôles of water and electrolyte redistribution remain to be elucidated.
ASJC Scopus subject areas
- Pharmacology, Toxicology and Pharmaceutics(all)
- Pharmacology (medical)