Antihypertensive properties of furosemide.

The antihypertensive properties of single doses of furosemide were evaluated in 113 patients. Doses over 120 mg consistently produced a fall in arterial pressure whereas smaller doses did not. Thus 20 of 22 patients (90%) who received more than 120 mg had a 26 + 6% average reduction in mean arterial pressure. The hypotensive action began in 30 to 45 minutes, the nadir of the decrease occurred between 2 and 2X hours, and the hypotension usually lasted 10 to 12 hours. Repeated weekly doses of furosemide over a 2-month period in six patients were not associated with development of drug resistance. The antihypertensive properties of doses of furosemide of more than 120 mg seemed to be of about the same potency as ethacrynic acid. The antihypertensive effect of high doses of furosemide did not seem to be related to the diuretic effect or to the decrease in plasma volume. These studies have demonstrated that doses of furosemide of more than 120 mg consistently decreased arterial pressure. The usefulness of this agent in the long-term management of hypertension remains to be determined.