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The acute effects of metolazone on electrolyte and acid excretion in man
Author(s) -
Smiley Joseph W.,
Onesti Gaddo,
Swartz Charles
Publication year - 1972
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt1972133336
Subject(s) - chemistry , natriuresis , titratable acid , excretion , endocrinology , reabsorption , diuresis , medicine , urine , renal function , renal physiology , net acid excretion , acetazolamide , urine flow rate , zoology , sodium , biochemistry , biology , organic chemistry
The acute effects of oral metolazone were studied in 10 normal volunteers. During hydropenia, natriuresis was maximal in 1 ½ to 3 hours. Na excretion increased by a mean of 196 µEq per minute, Cl by 385 µEq per minute, K by 9.6 µEq per minute, free water reabsorption (T c H 2 O) by 1.2 ml. per minute, Ca by 0.4 µEq per minute, Mg by 0.4 µEq per minute, and P by 4.2 µEq per minute. During water diuresis, natriuresis was maximal in 11½ to 3 hours. Na excretion increased by 234 µEq per minute, Cl by 395 µEq per minute, K by 4.4 µEq per minute, Ca by 0.2 p.Eq per minute, Mg by 1.1 µEq per minute, P by 8 µEq per minute, and urine flow by 0.9 ml. per minute. Free water clearance (C H2o ) decreased by 1.4 ml. per minute. Urine pH decreased as titratable acidity increased. NH 4 and HCO 3 did not change significantly. A distal site of action is suggested by the decreased C H2o associated with an insignificant rise in urine volume. Associated proximal effect is suggested by the increased T c H 2 O and the significant increase in P excretion during hydration. The decrease in urine pH and the absence of significant bicarbonaturia are evidence against carbonic anhydrase inhibition. Metolazone produced no change in glomerular filtration rate or renal plasma flow, which suggests that metolazone may somehow alter renovascular resistance at the time of maximal diuresis.