From the Guidelines
The typical starting dose of metolazone is 2.5 mg once daily, and the maximum total daily dose is 20 mg. This dose can be adjusted based on the patient's response, and it's essential to monitor electrolytes, particularly potassium and sodium levels, as well as renal function during metolazone therapy 1. For patients with severe edema, treatment may begin with 5 to 10 mg once daily, and in some cases, the dose can be increased gradually to 20 mg once daily or 10 mg twice daily.
Key Considerations
- For elderly patients or those with renal impairment, a lower starting dose of 1.25 to 2.5 mg once daily is recommended.
- Metolazone is a thiazide-like diuretic that works by increasing the excretion of sodium and water from the body.
- It's particularly effective in patients with reduced renal function and is often used in combination with loop diuretics for resistant edema or heart failure.
Monitoring and Adjustments
- The medication should be taken at the same time each day for consistent effect.
- Patients should be monitored for signs of electrolyte imbalances, hypotension, or azotemia, and the dose should be adjusted accordingly.
- Diuretic resistance can generally be overcome by the intravenous administration of diuretics, the use of 2 or more diuretics in combination, or the use of diuretics together with drugs that increase renal blood flow 1.
From the FDA Drug Label
Effective dosage of metolazone tablets, USP, should be individualized according to indication and patient response. A single daily dose is recommended. Usual Single Daily Dosage Schedules Suitable initial dosages will usually fall in the ranges given. Edema of cardiac failure: Metolazone tablets, USP, 5 to 20 mg once daily. Edema of renal disease: Metolazone tablets, USP, 5 to 20 mg once daily. Mild to moderate essential hypertension: Metolazone tablets, USP, 2½ to 5 mg once daily
The dose of Metolazone is:
- 5 to 20 mg once daily for edema of cardiac failure or edema of renal disease
- 2½ to 5 mg once daily for mild to moderate essential hypertension 2
From the Research
Dose of Metolazone
The dose of metolazone varies depending on the condition being treated and the patient's response to the medication.
- A wide dose range of metolazone has been investigated, from less than or equal to 2.5 to 200 mg 3.
- However, in most studies, a low starting dose of less than or equal to 5 mg was used 3, 4.
- Specifically, doses of 2.5 to 5 mg oral metolazone daily have been used in patients with advanced dilated cardiomyopathy 4.
- A starting dose of 2.5 mg/d of metolazone has also been used in combination with furosemide for the treatment of fluid retention 5.
- For the treatment of hypertension, doses of 0.5,1.0, or 2.0 mg of metolazone have been used, with 0.5 mg being considered safe and effective 6.
- It is worth noting that metolazone has been associated with adverse events such as hyponatremia, hypokalemia, and worsening renal function, particularly at higher doses 7.
Key Findings
- Low-dose metolazone (less than or equal to 5 mg) is often used in combination with loop diuretics for the treatment of refractory heart failure 3, 4.
- Metolazone can potentiate the diuretic effects of furosemide, allowing for lower doses of furosemide to be used 5.
- The choice of dose and diuretic strategy should be individualized based on the patient's condition and response to treatment 7.