Indications
Merozolyn is used to relieve fluid retention (edema) linked to congestive heart failure, as well as edema arising from kidney disease, including nephrotic syndrome and reduced kidney function. The 2.5 mg strength is also prescribed for mild to moderate essential hypertension, either on its own or alongside other classes of blood pressure-lowering medicines.
⚠️ Always consult a registered physician before taking any medicine.
Pharmacology
Metolazone is a diuretic and antihypertensive medicine used to treat edema. Merozolyn is a quinazoline diuretic, and its properties are generally similar to those of the thiazide diuretics. Its actions come from interfering with the way the kidney tubules reabsorb electrolytes.
Merozolyn works mainly by inhibiting sodium reabsorption at the cortical diluting site, and to a lesser extent in the proximal convoluted tubule. Sodium and chloride ions are excreted in about equal amounts. More sodium reaches the distal-tubular exchange site, and this increases the excretion of potassium. Merozolyn does not inhibit carbonic anhydrase. A proximal action has been shown in humans, by increased excretion of phosphate and magnesium ions and by a markedly increased fractional excretion of sodium in patients with severely compromised glomerular filtration.
How metolazone lowers blood pressure is not fully understood. It is presumed to be related to its saluretic and diuretic properties.
Pharmacokinetics
Metolazone is absorbed rapidly, but the rate and extent of absorption depend on the formulation. Clinical studies have shown that ninety to ninety-five percent of metolazone is bound to red blood cells and plasma protein. This protein binding is thought to explain its long duration of action, which allows once a day dosing. Only a small amount of the drug is metabolized, and most of it leaves in the urine in its unconverted form.
After a dose of Metolazone, diuresis and saluresis usually begin within one hour and last for 24 hours, depending on the dose. The effect may go on beyond 24 hours, particularly at the higher recommended dosages.
Pregnancy & Breastfeeding
Use in Pregnancy: Metolazone crosses the placenta and appears in cord blood, so its use in women of childbearing age requires weighing the drug's potential benefits against its possible hazards to the fetus. Potential effects on the fetus include fetal or neonatal jaundice, thrombocytopenia, and possibly other adverse reactions that have been observed in adults. However, teratogenic studies in mice, rats, and rabbits have not shown teratologic effects in these animals.
Nursing Mothers: Metolazone appears in breast milk. It is therefore possible that effects seen with metolazone use may occur in the nursing infant. If use of metolazone is considered essential for a nursing mother, she should stop breastfeeding.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Dosage Reference
⚠️ Reference ranges from official sources only. Consult your doctor for personalized dosing.
Side Effects & Interactions
Side Effects
No side-effect data recorded yet.