Last reviewed on RxList: 11/6/2018
Zaroxolyn Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 11/6/2018

Zaroxolyn (metolazone tablets) is a quinazoline class diuretic/antihypertensive drug used to treat salt and water retention including edema accompanying congestive heart failure, and edema accompanying renal diseases, including the nephrotic syndrome and states of diminished renal function. Zaroxolyn is also used to treat hypertension, alone or in combination with other antihypertensive drugs of a different class. Zaroxolyn is available in generic form. Common side effects of Zaroxolyn tend to be mild and temporary and include:

The dose of Zaroxolyn to treat edema of cardiac failure or of renal disease is 5 to 20 mg once daily. The dose of Zaroxolyn to treat mild to moderate essential hypertension is 2½ to 5 mg once daily. Zaroxolyn may interact with lithium, diuretics, other antihypertensive drugs, alcohol, barbiturates, narcotics, digitalis, corticosteroids, ACTH, curariform drugs (such as tubocurarine), salicylates and other nonsteroidal anti-inflammatory drugs (NSAIDs), norepinephrine, insulin and oral antidiabetic agents, methenamine, and anticoagulants. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant before using Zaroxolyn; diuretics are only indicated in pregnancy when edema is caused by disease, and not the normal edema caused by pregnancy. Zaroxolyn passes into breast milk and is not recommended for use while breastfeeding.

Our Zaroxolyn (metolazone tablets) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


In the U.S., 1 in every 4 deaths is caused by heart disease. See Answer
Zaroxolyn Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • chest pain;
  • pounding heartbeats or fluttering in your chest;
  • easy bruising or bleeding;
  • a light-headed feeling, like you might pass out;
  • liver problems--nausea, upper stomach pain, itching, tiredness, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • low potassium--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling;
  • low levels of sodium in the body--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
  • other signs of an electrolyte imbalance--dry mouth, nausea, vomiting, weakness, drowsiness, lack of energy, muscle pain, little or no urination, or feeling restless; or
  • severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects may include:

  • dizziness, spinning sensation;
  • drowsiness, tiredness;
  • depressed mood;
  • muscle or joint pain;
  • numbness or tingly feeling;
  • nausea, stomach pain, loss of appetite; or
  • diarrhea, constipation.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Zaroxolyn (Metolazone Tablets)


Heart Disease: Symptoms, Signs, and Causes See Slideshow
Zaroxolyn Professional Information


ZAROXOLYN is usually well tolerated, and most reported adverse reactions have been mild and transient. Many ZAROXOLYN 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.


Chest pain/discomfort, orthostatic hypotension, excessive volume depletion, hemoconcentration, venous thrombosis, palpitations.

Central And Peripheral Nervous System

Syncope, neuropathy, vertigo, paresthesias, psychotic depression, impotence, dizziness/lightheadedness, drowsiness, fatigue, weakness, restlessness (sometimes resulting in insomnia), headache.


Toxic epidermal necrolysis (TEN), Stevens-Johnson Syndrome, necrotizing angiitis (cutaneous vasculitis), skin necrosis, purpura, petechiae, dermatitis (photosensitivity), urticaria, pruritus, skin rashes.


Hepatitis, intrahepatic cholestatic jaundice, pancreatitis, vomiting, nausea, epigastric distress, diarrhea, constipation, anorexia, abdominal bloating, abdominal pain.


Aplastic/hypoplastic anemia, agranulocytosis, leukopenia, thrombocytopenia.


Hypokalemia, hyponatremia, hyperuricemia, hypochloremia, hypochloremic alkalosis, hyperglycemia, glycosuria, increase in serum urea nitrogen (BUN) or creatinine, hypophosphatemia, hypomagnesemia, hypercalcemia.


Joint pain, acute gouty attacks, muscle cramps or spasm.


Transient blurred vision, chills, dry mouth.

In addition, adverse reactions reported with similar antihypertensive-diuretics, but which have not been reported to date for ZAROXOLYN include: bitter taste, sialadenitis, xanthopsia, respiratory distress (including pneumonitis), and anaphylactic reactions. These reactions should be considered as possible occurrences with clinical usage of ZAROXOLYN.

Whenever adverse reactions are moderate or severe, ZAROXOLYN dosage should be reduced or therapy withdrawn.

Read the entire FDA prescribing information for Zaroxolyn (Metolazone Tablets)

© Zaroxolyn Patient Information is supplied by Cerner Multum, Inc. and Zaroxolyn Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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