What is the maximum recommended dose of metolazone (diuretic) per day?

Maximum Recommended Dose of Metolazone

The maximum recommended daily dose of metolazone is 20 mg per day. 1, 2

Dosing Guidelines for Metolazone

General Dosing

• The initial dose of metolazone typically ranges from 2.5-5 mg once daily, with subsequent dose adjustments based on clinical response 1, 3
• For treatment of edema in heart failure, the recommended dosage range is 5-20 mg once daily 2
• For treatment of edema in renal disease, the recommended dosage range is also 5-20 mg once daily 2
• For hypertension, a lower dosage range of 2.5-5 mg once daily is typically used 2

Burst Therapy in Heart Failure

• When used as "burst therapy" for refractory fluid retention in heart failure patients, metolazone is typically prescribed at 2.5 mg once daily for 2-3 days in combination with a loop diuretic 3
• This short-term approach helps avoid excessive diuresis and electrolyte abnormalities while maximizing the synergistic effect with loop diuretics 3, 4

Administration Considerations

• Metolazone should be administered as a single daily dose 2
• When used in combination with loop diuretics, metolazone should be given 30 minutes before the loop diuretic to maximize sequential nephron blockade 3, 4
• The duration of action of metolazone is 12-24 hours, which is longer than many other thiazide diuretics 1

Monitoring and Safety

• Careful monitoring is essential when using metolazone, particularly for:

  • Electrolyte imbalances, especially hypokalemia and hyponatremia 1, 3
  • Renal function, as azotemia may occur 1
  • Daily weight, with target weight reduction of 0.5-1.0 kg per day during therapy 3, 4
  • Blood pressure, as hypotension may occur 3

• Severe electrolyte and volume depletion can occur when metolazone is combined with a loop diuretic, requiring careful monitoring 1

Special Considerations

• Metolazone maintains efficacy even at lower glomerular filtration rates, unlike other thiazides that lose effectiveness when GFR falls below 30-40 ml/min 1, 5
• Hospital admission may be warranted when initiating combination therapy with loop diuretics in high-risk patients (those with hypotension, azotemia, oliguria, or ascites) 1, 3
• Lower doses (2.5-5 mg) are often effective and safer, particularly when used in combination with loop diuretics 5, 6

Clinical Evidence

• In studies of patients with refractory heart failure, metolazone doses of 1.25-10 mg daily have been effective when added to loop diuretics 7
• A retrospective study showed that metolazone at doses of 7.5-15 mg for one week improved diuretic response and congestion scores in patients with advanced heart failure 6
• Even low doses of metolazone (2.5 mg) can significantly potentiate the effects of furosemide in patients with severe fluid retention 8

Remember that while the maximum recommended dose is 20 mg daily, the lowest effective dose should be used to minimize adverse effects, particularly when combined with other diuretics.