The hypotensive effect of amiloride hydrochloride (MK-870) was investigated in mild hypertensive patients by means of a crossover trial comparing the effects of amiloride (15 mg. daily), hydrochlorothiazide (50 mg. daily), and amiloride (15 mg. daily) + hydrochlorothiazide (50 mg. daily). Amiloride was found to have a mild non-postural hypotensive effect indistinguishable from that of hydrochlorothiazide. The combination of the two agents produced no further hypotensive effect. This particular combination of the agents was thought to be too potent, as two patients had to withdraw owing to excessive diuresis and the average blood urea rose significantly while on the two diuretics. However, it was noted that when the two agents were combined the plasma potassium remained near pretreatment levels, whereas with hydrochlorothiazide alone the plasma potassium tended to fall and on amiloride alone it rose. © 1968, British Medical Journal Publishing Group. All rights reserved.
