The biochemical disturbance produced by
thiazide diuretics and by
amiloride during treatment of moderate
hypertension were compared. Two parallel studies were initiated. In one 40 patients with newly diagnosed
hypertension were treated with
metoprolol and a
diuretic, either
hydrochlorothiazide or
amiloride. In a second study 38 patients receiving longstanding treatment with hypotensives and
thiazides either continued the treatment or replaced the
thiazide with
amiloride. Initial biochemical assessments were compared with those after two years in the study. In previously untreated patients,
thiazide produced a significant fall in plasma
potassium and hyperuricaemia that did not occur with
amiloride (p less than 0.001). Those patients receiving long term treatment for their
hypertension who continued to take
thiazides had persistent hypokalaemia and hyperuricaemia. Substitution with
amiloride corrected the hypokalaemia and serum
uric acid returned toward normal ranges, but this change was not statistically significant. Patients receiving long term treatment also had
impaired glucose tolerance, this remained unchanged in those receiving
thiazide but was corrected in those receiving
amiloride. Compared with
amiloride thiazides produced undesirable but reversible biochemical changes. As control of
hypertension was equally effective with both preparations, we suggest that a combination of
amiloride with a beta blocker in treatment of moderate
hypertension in preferred.