metolazone, Zaroxolyn, Diulo (Discontinued); Mykrox (Discontinued)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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GENERIC NAME: metolazone

BRAND NAME: Zaroxolyn

DISCONTINUED BRANDS: Diulo, Mykrox

DRUG CLASS AND MECHANISM: Metolazone is a diuretic ("water pill") used in the treatment of high blood pressure and fluid accumulation. It works by blocking salt and fluid retention by the kidneys, thereby increasing urinary output of salt and water (diuresis). Although it is not a true thiazide, metolazone is chemically related to the thiazide class of diuretics (for example, chlorthalidone [Hygroton], hydrochlorothiazide), and works in a similar manner. Zaroxolyn is the original formulation of metolazone, and Diulo is similar. The absorption of these two drugs is relatively incomplete. Mykrox has more complete absorption. Therefore, less Mykrox needs to be given to have the same effects as a larger dose of Zaroxolyn or Diulo. Metolazone was approved by the FDA in 1973.

PRESCRIBED FOR: Metolazone is used in the treatment of high blood pressure and edema (fluid retention).

SIDE EFFECTS: Metolazone generally is well tolerated. Common side effects of metolazone are:

About 1 out of every 10 patients report dizziness, lightheadedness, and headache. Fatigue has been reported in 1 out of every 25 patients. About 1 out of every 50 patients reports:

Medically Reviewed by a Doctor on 4/3/2015

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