The renin-angiotensin-aldosterone system and blood pressure during oxprenolol treatment in hypertensive patients pretreated with diuretics.

The interrelationship between PRA, urinary aldosterone excretion, and blood pressure was studied in 11 patients with essential hypertension while receiving a diuretic (1st week) and subsequently a diuretic + oxprenolol (2nd week). The diuretic reduced blood pressure and body weight but increased PRA and aldosterone. Oxprenolol reduced PRA on the 1st day but to a lesser extent on the 7th day. Blood pressure was decreased 1 day after oxprenolol administration, but to a greater extent on the 7th day. Blood pressure decrements were independent of renin suppression, but directly correlated to aldosterone changes. These data suggest that the hypotensive effect of oxprenolol in patients receiving diuretic treatment is independent of its suppression of renin. Aldosterone suppression may instead contribute to the hypotensive effect of the drug.