metolazona

Metolazone is a thiazide-like diuretic used to treat edema and hypertension. It belongs to the benzothiadiazine class and acts by inhibiting the Na-Cl cotransporter in the distal convoluted tubule, increasing the excretion of sodium and water. Because of its potency and pharmacologic profile, metolazone is often used for diuretic-resistant edema and can be combined with a loop diuretic to enhance diuresis, particularly in congestive heart failure, cirrhosis, or nephrotic syndrome.

Medical uses include management of edema associated with congestive heart failure, liver cirrhosis, and nephrotic syndrome, as well as an adjunct for hypertension where additional diuretic effect is needed. It is sometimes used in patients who have a partial response to other diuretics or to overcome loop diuretic resistance.

Administration and dosing notes: metolazone is given orally. A common starting dose is 2.5 mg once daily, with potential titration to 5–10 mg; maximum doses can reach up to 20 mg daily. Onset is typically within 1–2 hours, with effects lasting roughly 24–72 hours. When used with a loop diuretic, metolazone is often administered shortly before the loop agent.

Adverse effects and safety: the drug can cause electrolyte disturbances, including hypokalemia, hyponatremia, and hypomagnesemia, as well as hyperuricemia and gout. Dehydration, hypotension, dizziness, and photosensitivity are possible. It may interact with NSAIDs (reducing diuretic efficacy), lithium (risk of toxicity), and other antihypertensives, particularly those that affect potassium balance.

Contraindications and monitoring: contraindicated in anuria and caution is advised in sulfonamide allergy, significant renal impairment, and during pregnancy or lactation unless clearly needed. Monitoring should include electrolytes, uric acid, renal function, and blood pressure.