Introduction

A quinazoline-sulfonamide that is considered a thiazide-like diuretic which is long-acting so useful in chronic renal failure. It also tends to lower blood pressure and increase potassium loss.

Uses

Metolazone is a thiazide-like diuretic used to treat hypertension.

For the treatment of hypertension, alone or in combination with other antihypertensive drugs of a different class.

Associated Conditions

Edema
Mild Hypertension
Moderate Hypertension

Pharmacodynamics

Metolazone is a quinazoline diuretic, with properties generally similar to the thiazide diuretics. A proximal action of metolazone 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. This action has been demonstrated in animals by micropuncture studies.

Mechanism of Action

The actions of metolazone result from interference with the renal tubular mechanism of electrolyte reabsorption. Metolazone acts primarily to inhibit sodium reabsorption at the cortical diluting site and to a lesser extent in the proximal convoluted tubule. Sodium and chloride ions are excreted in approximately equivalent amounts. The increased delivery of sodium to the distal tubular exchange site results in increased potassium excretion. Metolazone does not inhibit carbonic anhydrase. The antihypertensive mechanism of action of metolazone is not fully understood but is presumed to be related to its saluretic and diuretic properties.

Absorption

Peak blood levels are obtained within 2 to 4 hours of oral administration. The rate and extent of absorption are formulation dependent.

Protein Binding

50-70% bound to erythrocytes, up to 33% bound to plasma proteins, 2-5% of the drug in circulation is unbound

Route of Elimination

Most of the drug is excreted in the unconverted form in the urine.

Half Life

Approximately 14 hours.

Toxicity

Symptoms of overdose include difficulty breathing, dizziness, dizziness on standing up, drowsiness, fainting, irritation of the stomach and intestines, and lethargy leading to coma.

Food Interactions

Take with food. Food reduces irritation.

Dosage

Effective dosage of Metolazone should be individualized according to indications and patient response. A single daily dose is recommended. Therapy with Merozolyn should be titrated to gain an initial therapeutic response and to determine the minimal dose possible to maintain the desired therapeutic response.

Usual Dosages-

Edema of cardiac failure: Metolazone 5-10 mg, once daily
Edema of renal disease: Metolazone 5-20 mg, once daily

Treatment of Edematous States: The time interval for the initial dosage to show effect may vary; diuresis and saluresis usually begin within one hour and persist for 12 to 24 hours, depending on dosage. When a desired therapeutic effect has been obtained, it may be advisable to reduce the dose, if possible. The daily dose depends on the severity of the patients condition, sodium intake and responsiveness. A decision to change the daily dose should be based upon the results of thorough clinical and laboratory determinations. If antihypertensive drugs or diuretics are given concurrently with Merozolyn, more careful dosage adjustment may be necessary. For patients with congestive cardiac failure who tend to experience paroxysmal nocturnal dyspnea, it is usually advisable to employ a dosage near the upper end of the range to ensure prolongation of diuresis and saluresis for a full 24-hour period.

Hypertension: Mild to moderate essential hypertension: Metolazone 2.5-5 mg, once daily.

Treatment of Hypertension: The time interval required for the initial dosage regimen of Metolazone to show effect may vary from three to four days, to three to six weeks, in the treatment of elevated blood pressure. Doses should be adjusted at appropriate intervals to achieve maximum therapeutic effect.

Generic Name	Metolazone
Bangla Name	মেটোলাজোন
Available brands	1
Language	English বাংলা

Metolazone