Metolazone is a thiazide-like diuretic marketed under the brand names Zytanix, Metoz, Zaroxolyn, and Mykrox.

Metolazone is sometimes used together with loop diuretics such as furosemide or bumetanide, but these highly effective combinations can lead to dehydration and electrolyte abnormalities.

[1] One of the primary uses of metolazone is for treating edema (fluid retention) associated with congestive heart failure (CHF).

In addition to preventing fluid buildup, the use of metolazone may allow the patient to relax the amount of sodium restriction that is required.

[citation needed] This gives it a considerable advantage over other thiazide diuretics, since renal and heart failure often coexist and contribute to fluid retention.

Chronic kidney disease causes excess fluid retention that is often treated with diet adjustments and diuretics.

[4] The primary target of all thiazide diuretics, including metolazone, is the distal convoluted tubule, part of the nephron in the kidney, where they inhibit the sodium-chloride symporter.

Metolazone and the other thiazide diuretics inhibit the function of the sodium-chloride symporter, preventing sodium and chloride, and therefore water too, from leaving the lumen to enter the tubule cell.

Since most of the sodium in the lumen has already been reabsorbed by the time the filtrate reaches the distal convoluted tubule, thiazide diuretics have limited effects on water balance and on electrolyte levels.

[4] The use of activated anthranilic acid derivatives facilitates the preparation of the amides in those cases where the amines are either unreactive or difficult to obtain.

Reaction with sodium borohydride in the presence of aluminum chloride selectively reduces the double bond to yield the diuretic agent metolazone (5).

Since metolazone (as well as other drugs like indapamide) acts on the same target as thiazides and behave in a similar pharmacologic fashion, it is, however, considered a "thiazide-like diuretic."