Hydrochlorothiazide-amiloride causes excessive urinary zinc excretion

Serum zinc levels and urinary zinc excretion were compared in 15 patients with essential hypertension taking chronically a combination of hydrochlorothiazide and amiloride as monotherapy, eight patients maintained with hydrochlorothiazide alone, and eight control subjects. Serum zinc values were statistically comparable in all three groups. However, urinary zinc excretion was abnormally elevated in the two patient groups. In the dosage used, amiloride did not have a zinc-sparing effect.