Overview
DESCRIPTION Metolazone Tablets, USP for oral administration contain 2.5 mg, 5 mg or 10 mg of metolazone USP, a diuretic/saluretic/antihypertensive drug of the quinazoline class. Metolazone has the molecular formula C 16 H 16 ClN 3 O 3 S, the chemical name 7-chloro-1,2,3,4-tetrahydro-2-methyl-4-oxo-3- o -tolyl-6-quinazolinesulfonamide, and a molecular weight of 365.84.
Mechanism of Action
CLINICAL PHARMACOLOGY Metolazone is a quinazoline diuretic, with properties generally similar to the thiazide diuretics. 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.
Indications
- INDICATIONS AND USAGE Metolazone is indicated for the treatment of salt and water retention including: • edema accompanying congestive heart failure; • edema accompanying renal diseases, including the nephrotic syndrome and states of diminished renal function. Metolazone is also indicated for the treatment of hypertension, alone or in combination with other antihypertensive drugs of a different class. Mykrox ® tablets, a more rapidly available form of metolazone, are intended for the treatment of new patients with mild to moderate hypertension.
Common Doses
- 5 mg
- 20 mg
- 2.5 mg
- 0.5 mg
Dosage
DOSAGE AND ADMINISTRATION Effective dosage of metolazone tablets should be individualized according to indication and patient response. A single daily dose is recommended. Therapy with metolazone tablets should be titrated to gain an initial therapeutic response and to determine the minimal dose possible to maintain the desired therapeutic response. Usual Single Daily Dosage Schedules Suitable initial dosages will usually fall in the ranges given. Edema of cardiac failure: Metolazone tablets, 5 mg to 20 mg once daily. Edema of renal disease: Metolazone tablets, 5 mg to 20 mg once daily.
Contraindications
- CONTRAINDICATIONS Anuria, hepatic coma or precoma, known allergy or hypersensitivity to metolazone.
Side Effects
- ADVERSE REACTIONS Metolazone is usually well tolerated and most reported adverse reactions have been mild and transient. Many metolazone related adverse reactions represent extensions of its expected pharmacologic activity and can be attributed to either its antihypertensive action or its renal/metabolic actions. The following adverse reactions have been reported. Several are single or comparably rare occurrences. Adverse reactions are listed in decreasing order of severity within body systems.
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.