Metolazone

Name: Metolazone

What Is Metolazone (Zaroxolyn)?

Metolazone is the generic form of the brand-name drug Zaroxolyn, which is used to treat high blood pressure and fluid retention.

Metolazone is in a class of drugs called diuretics, or "water pills," which work by causing the kidneys to reduce the amount of water and salt in the body by increasing the amount of urine.

The medication comes in an oral tablet form. Metolazone was developed in the 1970s by an Indian-born chemist named Dr. Bola Vithal Shetty. It was approved by the Food and Drug Administration (FDA) in 1973.

Metolazone Warnings

If you have liver or kidney failure, your doctor will probably tell you not to take metolazone. You should tell your doctor if you have the following conditions:

  • Diabetes
  • Gout
  • Systemic lupus erythematosus
  • Parathyroid
  • Heart disease
  • Kidney disease
  • Liver disease

Also, tell your physician if you are pregnant, plan to become pregnant or are breastfeeding while taking metolazone. Metolazone should not be used during pregnancy, unless absolutely necessary.

Metolazone treats high blood pressure, but it does not cure it. You should continue to take this drug even if you feel well. Do not stop taking metolazone without first consulting with your physician. Your doctor will likely start you on a low dose of metolazone and gradually increase the dose.

This medication may cause dizziness, lightheadedness, or fainting if you get up too quickly from a lying position. This symptom is more common when you first start metolazone.

Metolazone Brand Names

Metolazone may be found in some form under the following brand names:

  • Mykrox

  • Zaroxolyn

Metolazone Drug Class

Metolazone is part of the drug class:

  • Low Ceiling Sulfonamide Diuretics

Metolazone Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • other medications for high blood pressure
  • "loop diuretics" such as furosemide (Lasix) or torsemide (Demadex) and others
  • nonsteroidal anti-inflammatory medications such as ibuprofen (Motrin, Nuprin) or naproxen (Aleve) and salicylates
  • corticosteroids such as prednisone, hydrocortisone (Cortef), and dexamethasone (Decadron, Dexone, Hexadrol)
  • lithium (Eskalith, Lithobid)
  • medications for diabetes
  • probenecid (Benemid)
  • alcohol
  • narcotics
  • barbiturates such as amobarbital (Amytal), butalbital (Fioricet, Fiorinal), phenobarbital (Luminal) and others
  • digoxin
  • warfarin (Coumadin, Jantoven)

This is not a complete list of metolazone drug interactions. Ask your doctor or pharmacist for more information.

 

Metolazone Overdose

If you take too much metolazone call your doctor or Poison Contol Center, or seek emergency medical attention right away.

How should I take metolazone?

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Metolazone is usually taken only once per day.

You may need to limit salt in your diet while taking this medicine. Follow your doctor's instructions carefully.

While using metolazone, you may need frequent blood tests. Your blood and urine may both be tested if you have been vomiting or are dehydrated.

Metolazone can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using metolazone.

If you need surgery, tell the surgeon ahead of time that you are using metolazone. You may need to stop using the medicine for a short time.

If you are being treated for high blood pressure, keep using this medicine even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medicine for the rest of your life.

Store the tablets at room temperature away from heat, light, and moisture.

Metolazone Dosage and Administration

General

Formulation Considerations

  • Do not interchange Mykrox and bioequivalent formulations with Zaroxolyn and bioequivalent formulations.a e Mykrox tablets (no longer commercially available in US) are more rapidly and extensively absorbed than other metolazone formulations; not therapeutically equivalent to Zaroxolyn or other formulations of drug that share the latter’s slower and incomplete absorption.a e

BP Monitoring and Treatment Goals

  • Carefully monitor BP during initial titration or subsequent upward adjustment in dosage.500 501

  • When available, use evidence-based dosing information (i.e., dosages shown in randomized controlled trials to reduce complications of hypertension) to determine target dosages; target dosages usually can be achieved within 2–4 weeks but may take up to several months.501

  • If adequate BP response not achieved with a single antihypertensive agent, add a second drug with demonstrated benefit; if goal BP still not achieved with optimal dosages of 2 antihypertensive agents, add a third drug.501 May maximize dosage of the first drug before adding a second drug, or add a second drug before maximizing dosage of the initial drug.501

  • Consider initiating antihypertensive therapy with a combination of drugs if patient's BP exceeds goal BP by >20/10 mm Hg.500 501 503 504

  • Goal is to achieve and maintain optimal control of BP; individualize specific target BP based on consideration of multiple factors, including patient age and comorbidities, and currently available evidence from clinical studies.500 501 (See Hypertension under Uses.)

Administration

Administer orally as a single daily dose.a e

Dosage

Dosage depends on specific formulation used and condition being treated.a

Individualize dosage according to individual requirements and response.a e

Adjust dosage to achieve an initial therapeutic response and to determine minimal dose necessary to maintain desired therapeutic response.e

For the management of fluid retention (e.g., edema) associated with heart failure, experts state that diuretics should be administered at a dosage sufficient to achieve optimal volume status and relieve congestion without inducing an excessively rapid reduction in intravascular volume, which could result in hypotension, renal dysfunction, or both.524

More careful dosage adjustment may be necessary in patients receiving concomitant therapy with other antihypertensive agents or diuretics.e (See Specific Drugs under Interactions.)

Pediatric Patients

Heart Failure†, Hypertension†, Bronchopulmonary Dysplasia†, Nephrotic Syndrome†, Nephrogenic Diabetes Insipidus† Oral

0.05–0.1 mg/kg once daily has been given.e (See Pediatric Use under Cautions.)

Prolonged use (beyond a few days) not recommended.e (See Pediatric Use under Cautions.)

Adults

Hypertension Oral (Zaroxolyn or another bioequivalent formulation)

Initial dosage of 1.25–2.5 mg once daily has been suggested.a

Usual dosage range is 2.5–5 mg once daily.109 500 e

If adequate response is not achieved with monotherapy, add another antihypertensive agent.501

If intolerable adverse effects occur, consider dosage reduction; if adverse effects worsen or fail to resolve, may need to discontinue and switch to another antihypertensive drug class.501

Edema in Heart Failure Monotherapy Oral (Zaroxolyn or another bioequivalent formulation)

Manufacturer recommends a usual initial dosage range of 5–20 mg once daily.109 e

Some experts recommend an initial dosage of 2.5 mg once daily up to a maximum total daily dosage of 20 mg.524

Has been administered every other day after response of patient was stabilized.28

Daily dosage depends on severity of patient’s condition, sodium intake, and responsiveness.e Adjust daily dosage based on results of thorough clinical and laboratory evaluations.e

Reduction of dosage to a lower maintenance level may be possible if desired therapeutic response attained.e

High doses may prolong diuresis and saluresis; single daily dose is recommended.e (See Absorption under Pharmacokinetics.)

Combination Therapy Oral (Zaroxolyn or another bioequivalent formulation)

For sequential nephron blockade in the management of fluid retention (e.g., edema) in heart failure, some experts recommend an initial dosage of 2.5–10 mg once daily in combination with a loop diuretic.524

Edema in Renal Diseases Oral (Zaroxolyn or another bioequivalent formulation)

Usual initial dosage range is 5–20 mg once daily.109 e

Daily dosage depends on severity of patient’s condition, sodium intake, and responsiveness.e Adjust daily dosage based on results of thorough clinical and laboratory evaluations.e

Reduction of dosage to a lower maintenance level may be possible if desired therapeutic response attained.e

High doses may prolong diuresis and saluresis; single daily dose is recommended.e (See Absorption under Pharmacokinetics.)

Prescribing Limits

Adults

Hypertension Oral

Usual maximum is 5 mg daily.a

Edema in Heart Failure Monotherapy Oral (Zaroxolyn or another bioequivalent formulation)

Maximum total daily dose recommended by ACCF/AHA: 20 mg.524

Special Populations

Hepatic Impairment

No specific dosage recommendations.e (See Hepatic Impairment under Cautions.)

Renal Impairment

No specific dosage recommendations.e (See Renal Impairment under Cautions.)

Geriatric Patients

Select dosage with caution, usually initiating therapy at the low end of the dosing range, because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.e (See Geriatric Use under Cautions.)

Paroxysmal Nocturnal Dyspnea Patients

May be advisable to administer an increased dosage in the management of edematous conditions to ensure prolongation of diuresis and saluresis for a full 24-hour period.e

Stability

Storage

Oral

Tablets

Tight, light-resistant containers at 25°C (may be exposed to 15–30°C).a e

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

metOLazone

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablets

2.5 mg*

metOLazone Tablets

Zaroxolyn

UCB

5 mg*

metOLazone Tablets

Zaroxolyn

UCB

10 mg*

metOLazone Tablets

Commonly used brand name(s)

In the U.S.

  • Mykrox
  • Zaroxolyn

Available Dosage Forms:

  • Tablet

Therapeutic Class: Cardiovascular Agent

Pharmacologic Class: Diuretic

Chemical Class: Thiazide Related

Uses For metolazone

Metolazone is used to treat fluid retention (edema) and swelling that is caused by congestive heart failure, kidney disease, or other medical conditions .

Metolazone is also used alone or together with other medicines to treat high blood pressure (hypertension). High blood pressure adds to the work load of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled .

Metolazone is a thiazide diuretic (water pill). It reduces the amount of water in the body by increasing the flow of urine, which helps to lower blood pressure .

metolazone is available only with your doctor's prescription .

How do I store and/or throw out Metolazone?

  • Store at room temperature.
  • Protect from light.
  • Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Check with your pharmacist about how to throw out unused drugs.

Contraindications

Anuria, hepatic coma or precoma, known allergy or hypersensitivity to Metolazone.

How is Metolazone Supplied

Upstate's Metolazone tablets, USP, are shallow biconvex, round tablets, and are available in three strengths:

2½ mg, pink, debossed "643" on one side, and "2½" on reverse side.

NDC 65580-643-71 Bottle of 100's

5 mg, blue, debossed "644" on one side, and "5" on reverse side.

NDC 65580-644-71 Bottle of 100's

10 mg, yellow, debossed "645" on one side, and "10" on reverse side.

NDC 65580-645-71 Bottle of 100's

Storage

Store at 25°C (77°F); excursions permitted to 15°-30°C (59°-86°F) [See USP Controlled Room Temperature].

Protect from light. Keep out of the reach of children.

For more information about Metolazone Tablets, USP call 1-844-599-CARE (2273).

Manufactured for:

UPSTATE
PHARMA,LLC
Smyrna, GA 30080 USA

©2015, UCB, Inc., Smyrna, GA 30080
All rights reserved.

Rev. 01/2015

PRINCIPAL DISPLAY PANEL - 2½ mg Bottle Label

NDC 65580-643-71

Metolazone
Tablets, USP

2½ mg

Rx Only
100 Tablets

Manufactured for:
UPSTATE
PHARMA,LLC
Rochester, NY 14623 USA

Duration of Action

≥24 hours

Half-Life Elimination

6 to 20 hours

Protein Binding

90% to 95%

Dosing Hepatic Impairment

There are no dosage adjustments provided in manufacturer’s labeling; contraindicated in hepatic coma or precoma.

Administration

Administer orally as a single daily dose with or without food. Take early in day to avoid nocturia.

Drug Interactions

ACE Inhibitors: Thiazide and Thiazide-Like Diuretics may enhance the hypotensive effect of ACE Inhibitors. Thiazide and Thiazide-Like Diuretics may enhance the nephrotoxic effect of ACE Inhibitors. Monitor therapy

Ajmaline: Sulfonamides may enhance the adverse/toxic effect of Ajmaline. Specifically, the risk for cholestasis may be increased. Monitor therapy

Alcohol (Ethyl): May enhance the orthostatic hypotensive effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Alfuzosin: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Allopurinol: Thiazide and Thiazide-Like Diuretics may enhance the potential for allergic or hypersensitivity reactions to Allopurinol. Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Allopurinol. Specifically, Thiazide Diuretics may increase the concentration of Oxypurinol, an active metabolite of Allopurinol. Monitor therapy

Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, blood pressure lowering medications should be withheld for 24 hours prior to amifostine administration. If blood pressure lowering therapy cannot be withheld, amifostine should not be administered. Consider therapy modification

Aminolevulinic Acid (Systemic): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Systemic). Avoid combination

Aminolevulinic Acid (Topical): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Topical). Monitor therapy

Amphetamines: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Analgesics (Opioid): May enhance the adverse/toxic effect of Diuretics. Analgesics (Opioid) may diminish the therapeutic effect of Diuretics. Monitor therapy

Anticholinergic Agents: May increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Antidiabetic Agents: Thiazide and Thiazide-Like Diuretics may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy

Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy

Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Monitor therapy

Barbiturates: May enhance the orthostatic hypotensive effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Beta2-Agonists: May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Bile Acid Sequestrants: May decrease the absorption of Thiazide and Thiazide-Like Diuretics. The diuretic response is likewise decreased. Consider therapy modification

Brigatinib: May diminish the antihypertensive effect of Antihypertensive Agents. Brigatinib may enhance the bradycardic effect of Antihypertensive Agents. Monitor therapy

Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Calcium Salts: Thiazide and Thiazide-Like Diuretics may decrease the excretion of Calcium Salts. Continued concomitant use can also result in metabolic alkalosis. Monitor therapy

CarBAMazepine: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of CarBAMazepine. Specifically, there may be an increased risk for hyponatremia. Monitor therapy

Cardiac Glycosides: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Cardiac Glycosides. Specifically, cardiac glycoside toxicity may be enhanced by the hypokalemic and hypomagnesemic effect of thiazide diuretics. Monitor therapy

Corticosteroids (Orally Inhaled): May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Corticosteroids (Systemic): May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Cyclophosphamide: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Cyclophosphamide. Specifically, granulocytopenia may be enhanced. Monitor therapy

Dexketoprofen: May enhance the adverse/toxic effect of Sulfonamides. Monitor therapy

Diacerein: May enhance the therapeutic effect of Diuretics. Specifically, the risk for dehydration or hypokalemia may be increased. Monitor therapy

Diazoxide: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Diazoxide. Monitor therapy

Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Dofetilide: Thiazide and Thiazide-Like Diuretics may enhance the QTc-prolonging effect of Dofetilide. Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Dofetilide. Avoid combination

DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Monitor therapy

Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Herbs (Hypotensive Properties): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Monitor therapy

Ipragliflozin: May enhance the adverse/toxic effect of Thiazide and Thiazide-Like Diuretics. Specifically, the risk for intravascular volume depletion may be increased. Monitor therapy

Ivabradine: Thiazide and Thiazide-Like Diuretics may enhance the arrhythmogenic effect of Ivabradine. Monitor therapy

Levodopa: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa. Monitor therapy

Levosulpiride: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Levosulpiride. Avoid combination

Licorice: May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Lithium: Thiazide and Thiazide-Like Diuretics may decrease the excretion of Lithium. Consider therapy modification

Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Mecamylamine: Sulfonamides may enhance the adverse/toxic effect of Mecamylamine. Avoid combination

Methylphenidate: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Multivitamins/Fluoride (with ADE): May enhance the hypercalcemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Multivitamins/Minerals (with ADEK, Folate, Iron): Thiazide and Thiazide-Like Diuretics may enhance the hypercalcemic effect of Multivitamins/Minerals (with ADEK, Folate, Iron). Monitor therapy

Multivitamins/Minerals (with AE, No Iron): Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Multivitamins/Minerals (with AE, No Iron). Specifically, thiazide diuretics may decrease the excretion of calcium, and continued concomitant use can also result in metabolic alkalosis. Monitor therapy

Naftopidil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicergoline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: Thiazide and Thiazide-Like Diuretics may enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Nonsteroidal Anti-Inflammatory Agents may diminish the therapeutic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Consider therapy modification

OXcarbazepine: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of OXcarbazepine. Specifically, there may be an increased risk for hyponatremia. Monitor therapy

Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Monitor therapy

Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Porfimer: Photosensitizing Agents may enhance the photosensitizing effect of Porfimer. Monitor therapy

Promazine: Thiazide and Thiazide-Like Diuretics may enhance the QTc-prolonging effect of Promazine. Avoid combination

Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Reboxetine: May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Selective Serotonin Reuptake Inhibitors: May enhance the hyponatremic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Sodium Phosphates: Diuretics may enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with diuretics, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, hydrate adequately and monitor fluid and renal status. Consider therapy modification

Topiramate: Thiazide and Thiazide-Like Diuretics may enhance the hypokalemic effect of Topiramate. Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Topiramate. Management: Monitor for increased topiramate levels/adverse effects (e.g., hypokalemia) with initiation/dose increase of a thiazide diuretic. Closely monitor serum potassium concentrations with concomitant therapy. Topiramate dose reductions may be necessary. Consider therapy modification

Toremifene: Thiazide and Thiazide-Like Diuretics may enhance the hypercalcemic effect of Toremifene. Monitor therapy

Verteporfin: Photosensitizing Agents may enhance the photosensitizing effect of Verteporfin. Monitor therapy

Vitamin D Analogs: Thiazide and Thiazide-Like Diuretics may enhance the hypercalcemic effect of Vitamin D Analogs. Monitor therapy

Yohimbine: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Warnings/Precautions

Concerns related to adverse effects:

• Electrolyte disturbances: Severe hypokalemia and/or hyponatremia can occur rapidly following initial doses. Hypercalcemia, hypochloremic alkalosis, and/or hypomagnesemia can also occur.

• Hypersensitivity: Sensitivity reactions, including angioedema and bronchospasm, may occur.

• Orthostatic hypotension: Orthostatic hypotension may occur. Ethanol may potentiate orthostatic hypotensive effect of metolazone. Instruct patients to avoid ethanol during therapy. If taken concurrently, monitor for hypotensive effects.

• Photosensitivity: Photosensitization may occur.

• Renal effects: Azotemia and oliguria may occur.

• Sulfonamide (“sulfa”) allergy: The FDA-approved product labeling for many medications containing a sulfonamide chemical group includes a broad contraindication in patients with a prior allergic reaction to sulfonamides. There is a potential for cross-reactivity between members of a specific class (eg, two antibiotic sulfonamides). However, concerns for cross-reactivity have previously extended to all compounds containing the sulfonamide structure (SO2NH2). An expanded understanding of allergic mechanisms indicates cross-reactivity between antibiotic sulfonamides and nonantibiotic sulfonamides may not occur or at the very least this potential is extremely low (Brackett 2004; Johnson 2005; Slatore 2004; Tornero 2004). In particular, mechanisms of cross-reaction due to antibody production (anaphylaxis) are unlikely to occur with nonantibiotic sulfonamides. T-cell-mediated (type IV) reactions (eg, maculopapular rash) are less well understood and it is not possible to completely exclude this potential based on current insights. In cases where prior reactions were severe (Stevens-Johnson syndrome/TEN), some clinicians choose to avoid exposure to these classes.

Disease-related concerns:

• Adrenal insufficiency: Avoid use of diuretics for treatment of elevated blood pressure in patients with primary adrenal insufficiency (Addison disease). Adjustment of glucocorticoid/mineralocorticoid therapy and/or use of other antihypertensive agents is preferred to treat hypertension (Bornstein 2016; Inder 2015).

• Diabetes: Use with caution in patients with prediabetes or diabetes mellitus; may see a change in glucose control.

• Gout: Hyperuricemia can occur and gout can be precipitated.

• Hepatic impairment: Use with caution in patients with severe hepatic dysfunction.

• Hypokalemia: Use with caution in patients with hypokalemia; correct before initiating therapy.

• Renal impairment: Use caution in severe renal disease. If azotemia and oliguria worsen during treatment in these patients, discontinue therapy.

• Systemic lupus erythematosus (SLE): Can cause SLE exacerbation or activation.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

• Interchangeability: Do not interchange Zaroxolyn with other formulations of metolazone that are not therapeutically equivalent at the same doses (eg, Mykrox, no longer available in the US).

Special populations:

• Surgical patients: If given the morning of surgery, metolazone may render the patient volume depleted and blood pressure may be labile during general anesthesia.

Administrative Information

LactMed Record Number

181

Last Revision Date

20150310

Disclaimer

Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

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