Forty-six hypertensive patients have received diazoxide intravenously. Three hundred milligrams (one ampule) administered rapidly undiluted resulted in a 27 per cent average reduction in mean arterial pressure in 1 to 2 minutes. During the next 3 to 5 minutes the arterial pressure increased gradually to a 15 per cent average reduction as compared to the control. The average duration of diazoxide in these patients was 4.7 ± 1.7 hours. No signs of postural hypotension, cerebral ischemia, or collapse were noted. At the peak of hypotensive action there was a 41 per cent average reduction in total peripheral resistance. Repeated doses of diazoxide in both nonpregnant patients with acute hypertension and pregnant patients with toxemia adequately controlled the arterial pressure and were not associatetd with the development of drug resistance. The standard dosage of 300 mg. (one ampule), the immediate onset of action and the moderately long duration of action, the maintenance of cardiac output, the lack of significant side effects, and the fact that it can be administered repeatedly without the development of drug resistance make diazoxide administered intravenously the ideal therapy for acute hypertension.
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