Generic name: Metolazone.

Other brand name: Mykrox.

Zaroxolyn is a thiazide diuretic. It reduces fluid accumulation in the body.

Quick Facts About Zaroxolyn


Used to treat high blood pressure and other conditions requiring elimination of excess fluid from the body, including congestive heart failure and kidney disease. May be prescribed with or without other high blood pressure medications. Sometimes prescribed for kidney stones.

Zaroxolyn Dosage

If taking for high blood pressure, must take regularly for it to be effective. May take several weeks to observe the effects of Zaroxolyn. Continue to take even when symptoms disappear.

  • Usual adult dose: for heart or kidney disease — 5 to 20 milligrams taken once per day. For mild to moderate high blood pressure — 2.5 to 5 milligrams taken once per day. Doctor will prescribe lowest dose possible.
  • Usual child dose: not generally prescribed for children.
  • Missed dose: take as soon as possible, unless it is the next day. In that case, do not take the missed dose; go back to regular schedule. Do not double doses.

Zaroxolyn Side Effects

Overdose symptoms:

difficulty breathing, dizziness, drowsiness, fainting, irritation of stomach and intestines, lethargy, leading to coma. If you suspect an overdose, immediately seek medical attention.

More common side effects: abdominal bloating, anemia, blood clots, blurred vision, chest pain, chills, constipation, depression, diarrhea, dizziness, drowsiness, fainting, fatigue, gout, headache, hepatitis, high blood sugar, hives, impotence, inflammation of the skin, inflammation of the pancreas, joint pain, loss of appetite, low potassium levels, muscle spasms or cramps, nausea, rapid or pounding heartbeat, rash, reddish or purplish skin spots, restlessness, sensitivity to light, sugar in the urine, tingling or pins and needles, upset stomach, vertigo, vomiting, weakness, yellow eyes and skin.

No known less common or rare Zaroxolyn side effects.


Inform your doctor before combining Zaroxolyn with:

acth; antidiabetic medications such as Micronase; barbiturates such as phenobarbital; corticosteroids such as prednisone (Deltasone); digitalis (Lanoxin); lithium (Lithonate); loop diuretics such as furosemide (Lasix); methenamine (Mandelamine); narcotics such as Percocet; nonsteroidal anti-inflammatory medications such as Advil; norepinephrine (Levophed); other high blood pressure medications such as Aldomet.

Avoid alcohol during Zaroxolyn therapy.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Appears in breast milk; could affect a nursing infant.

No special precautions apply to seniors.

Not generally prescribed for children.

  • Should not take if you are unable to urinate or have severe kidney disease.
  • Avoid if sensitive to or allergic to Zaroxolyn or similar medications. If allergic to sulfa medications or quinethazone, at increased risk for allergic reaction.
  • Diuretics may cause potassium loss. Symptoms include muscle weakness and rapid or irregular heartbeat Doctor may advise a potassium supplement or eating potassium-rich foods.
  • Doctor should monitor kidney function during Zaroxolyn therapy.
  • Use with caution if you have liver disease, diabetes, gout or lupus erythematosus.
  • Fluid depletion (caused by dehydration, excessive sweating, severe diarrhea, or vomiting) may cause low blood pressure. Use care when exercising in hot weather.
  • Notify your doctor or dentist during a medical emergency or prior to surgery that you are taking Zaroxolyn.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Zaroxolyn side effects, please contact your healthcare provider