Metolazone

Metolazone
Black Box Warning
Adult Indications & Dosage
Pediatric Indications & Dosage
Contraindications
Warnings & Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Administration & Monitoring
Overdosage
Pharmacology
Clinical Studies
How Supplied
Images
Patient Counseling Information
Precautions with Alcohol
Brand Names
Look-Alike Names

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Gerald Chi

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Black Box Warning

DO NOT INTERCHANGE: See full prescribing information for complete Boxed Warning. * Do not interchange Zaroxolyn tablets and other formulations of metolazone that share its slow and incomplete bioavailability and are not therapeutically equivalent at the same doses to Mykrox® tablets, a more rapidly available and completely bioavailable metolazone product. Formulations bioequivalent to Zaroxolyn and formulations bioequivalent to Mykrox should not be interchanged for one another.

Overview

Metolazone is a thiazide-like diuretic that is FDA approved for the {{{indicationType}}} of edema associated with congestive heart failure or renal disease. Metolazone is also indicated for the treatment of hypertension, alone or in combination with other antihypertensive agents. There is a Black Box Warning for this drug as shown here. Common adverse reactions include orthostatic hypotension, electrolyte disturbances, hyperuricemia, dizziness, and fatigue.

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

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

Edema

• Dosing Information

• 5–20 mg PO qd

• The time interval required for the initial dosage to produce an effect may vary. Diuresis and saluresis usually begin within one hour and persist for 24 hours or longer. 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 patient's condition, sodium intake, and responsiveness. A decision to change the daily dose should be based on the results of thorough clinical and laboratory evaluations. If antihypertensive drugs or diuretics are given concurrently with ZAROXOLYN, more careful dosage adjustment may be necessary. For patients who tend to experience paroxysmal nocturnal dyspnea, it may be advisable to employ a larger dose to ensure prolongation of diuresis and saluresis for a full 24-hour period.

Mild to Moderate Essential Hypertension

• Dosing Information

• 2.5–5 mg PO qd

• The time interval required for the initial dosage regimen to show effect may vary from three or 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.

Off-Label Use and Dosage (Adult)

Guideline-Supported Use

There is limited information regarding Off-Label Guideline-Supported Use of Metolazone in adult patients.

Non–Guideline-Supported Use

Calcium Renal Calculus

• Dosing Information

• 2.5–10 mg PO qd

Edema Associated with Liver Disease

• Dosing Information

• 5–20 mg PO qd

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

Edema

• Safety and effectiveness in pediatric patients have not been established in controlled clinical trials.
• There is limited experience with the use of ZAROXOLYN in pediatric patients with congestive heart failure, hypertension, bronchopulmonary dysplasia, nephrotic syndrome and nephrogenic diabetes insipidus.
• Doses used generally ranged from 0.05 to 0.1 mg/kg administered once daily and usually resulted in a 1 to 2.8 kg weight loss and 150 to 300 cc increase in urine output. Not all patients responded and some gained weight. Those patients who did respond did so in the first few days of treatment. Prolonged use (beyond a few days) was generally associated with no further beneficial effect or a return to baseline status and is not recommended.

• Dosing Information

• 0.05–0.1 mg/kg qd

Off-Label Use and Dosage (Pediatric)

Guideline-Supported Use

There is limited information regarding Off-Label Guideline-Supported Use of Metolazone in pediatric patients.

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Metolazone in pediatric patients.

Contraindications

• Anuria
• Hepatic coma or precoma
• Allergy or hypersensitivity to metolazone

Warnings

DO NOT INTERCHANGE: See full prescribing information for complete Boxed Warning. * Do not interchange Zaroxolyn tablets and other formulations of metolazone that share its slow and incomplete bioavailability and are not therapeutically equivalent at the same doses to Mykrox® tablets, a more rapidly available and completely bioavailable metolazone product. Formulations bioequivalent to Zaroxolyn and formulations bioequivalent to Mykrox should not be interchanged for one another.

• Rapid Onset Hyponatremia And/Or Hypokalemia

• Rarely, the rapid onset of severe hyponatremia and/or hypokalemia has been reported following initial doses of thiazide and non-thiazide diuretics. When symptoms consistent with severe electrolyte imbalance appear rapidly, drug should be discontinued and supportive measures should be initiated immediately. Parenteral electrolytes may be required. Appropriateness of therapy with this class of drugs should be carefully reevaluated.

Precautions

• Description

Adverse Reactions

Clinical Trials Experience

There is limited information regarding Clinical Trial Experience of Metolazone in the drug label.

Central Nervous System

Cardiovascular

Respiratory

Gastrointestinal

Hypersensitivity

Miscellaneous

Postmarketing Experience

There is limited information regarding Postmarketing Experience of Metolazone in the drug label.

Central Nervous System

Cardiovascular

Respiratory

Gastrointestinal

Hypersensitivity

Miscellaneous

Drug Interactions

• Drug

• Description

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA):

• Pregnancy Category

Pregnancy Category (AUS):

• Australian Drug Evaluation Committee (ADEC) Pregnancy Category

There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Metolazone in women who are pregnant.

Labor and Delivery

There is no FDA guidance on use of Metolazone during labor and delivery.

Nursing Mothers

There is no FDA guidance on the use of Metolazone with respect to nursing mothers.

Pediatric Use

There is no FDA guidance on the use of Metolazone with respect to pediatric patients.

Geriatic Use

There is no FDA guidance on the use of Metolazone with respect to geriatric patients.

Gender

There is no FDA guidance on the use of Metolazone with respect to specific gender populations.

Race

There is no FDA guidance on the use of Metolazone with respect to specific racial populations.

Renal Impairment

There is no FDA guidance on the use of Metolazone in patients with renal impairment.

Hepatic Impairment

There is no FDA guidance on the use of Metolazone in patients with hepatic impairment.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Metolazone in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Metolazone in patients who are immunocompromised.

Administration and Monitoring

Administration

• Oral

• Intravenous

Monitoring

There is limited information regarding Monitoring of Metolazone in the drug label.

Condition1

• Description

IV Compatibility

There is limited information regarding IV Compatibility of Metolazone in the drug label.

Overdosage

Acute Overdose

Signs and Symptoms

• Description

Management

• Description

Chronic Overdose

There is limited information regarding Chronic Overdose of Metolazone in the drug label.

Pharmacology

Metolazone
Systematic (IUPAC) name
7-chloro-2-methyl-3-(2-methylphenyl)- 4-oxo-1,2-dihydroquinazoline-6-sulfonamide
Identifiers
CAS number	17560-51-9
ATC code	C03BA08
PubChem	4170
DrugBank	APRD01109
Chemical data
Formula	Template:OrganicBox atomTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBox
Mol. mass	365.835 g/mol
Pharmacokinetic data
Bioavailability	~65%
Metabolism	minimal
Half life	14 hours
Excretion	primarily urine
Therapeutic considerations
Pregnancy cat.	B
Legal status	Prescription only
Routes	Oral

Mechanism of Action

Structure

This image is provided by the National Library of Medicine.

Pharmacodynamics

There is limited information regarding Pharmacodynamics of Metolazone in the drug label.

Pharmacokinetics

There is limited information regarding Pharmacokinetics of Metolazone in the drug label.

Nonclinical Toxicology

There is limited information regarding Nonclinical Toxicology of Metolazone in the drug label.

Clinical Studies

There is limited information regarding Clinical Studies of Metolazone in the drug label.

Condition1

• Description

How Supplied

Storage

There is limited information regarding Metolazone Storage in the drug label.

Images

Drug Images

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Package and Label Display Panel

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Patient Counseling Information

There is limited information regarding Patient Counseling Information of Metolazone in the drug label.

Precautions with Alcohol

• Alcohol-Metolazone interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

Brand Names

• Mykrox®
• Zaroxolyn®

Look-Alike Drug Names

• metolazone — methimazole
• metolazone — metoclopramide

Drug Shortage Status

Price

References

The contents of this FDA label are provided by the National Library of Medicine.

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