What is the equivalent IV (intravenous) dose of torsemide for a patient with congestive heart failure (CHF) exacerbation when converting from PO (per oral)?

From the Guidelines

When converting from oral to IV torsemide for a patient with CHF exacerbation, a 1:1 conversion ratio is recommended, as supported by the pharmacokinetic properties of torsemide, although specific guidance on this conversion is not provided in the 2013 ACCF/AHA guideline for the management of heart failure 1. The key principle from the guideline is that if patients are already receiving loop diuretic therapy, the initial intravenous dose should equal or exceed their chronic oral daily dose 1. Given torsemide's nearly 100% bioavailability, a direct conversion from oral to IV can be considered, which means if a patient was taking 20 mg of oral torsemide, administering 20 mg IV would be appropriate. The typical IV dose range for CHF exacerbation is 10-20 mg once daily, though doses up to 200 mg have been used in severe cases. It's crucial to monitor the patient's response, electrolytes (particularly potassium), and renal function after conversion, as IV administration provides a more rapid onset of action compared to oral dosing. Adjust the dose based on clinical response and transition back to oral therapy when the patient stabilizes, keeping in mind the principles outlined in the guideline for managing heart failure, including prompt treatment with intravenous loop diuretics for significant fluid overload and adjusting the diuretic dose to relieve symptoms, reduce volume excess, and avoid hypotension 1. Key considerations include:

• Monitoring urine output and signs and symptoms of congestion
• Serially assessing the patient's condition to adjust the diuretic dose accordingly
• Being mindful of the potential for hypotension and adjusting the dose to avoid this complication.

From the Research

Torsemide PO to IV Conversion for CHF Exacerbation

• The equivalent IV dose of torsemide for a patient with congestive heart failure (CHF) exacerbation when converting from PO is not directly stated in the provided studies.
• However, study 2 mentions that the TRANSFORM-HF trial found no difference in clinical outcomes between torsemide versus furosemide after hospitalization for heart failure.
• The study 2 also categorizes patients into three groups by discharge diuretic dose: (1) ≤40 mg, (2) >40-80 mg, and (3) >80 mg of furosemide equivalents.
• According to study 3, the eligibility criteria included therapy at enrollment with oral dose not less than 175 mg per week of furosemide or equivalent weekly dose of torsemide, but it does not provide a direct conversion from PO to IV.

Diuretic Dosing and Outcomes

• Study 2 found that higher doses of furosemide and torsemide were associated with increased risk of all-cause hospitalization and the composite of all-cause mortality and hospitalization.
• Study 4 compared the effects of combination diuretic therapy with oral hydrochlorothiazide or intravenous chlorothiazide added to background intravenous loop diuretic therapy among patients hospitalized with heart failure.
• The study 4 found that urine output increased to a greater extent with intravenous chlorothiazide compared with oral hydrochlorothiazide.

Clinical Considerations

• Study 5 summarizes the basic features of diuretics, including their mechanism of action, indications, and adverse effects in heart failure.
• Study 6 found that ultrafiltration appears to be safe but might not provide significant benefits in terms of reducing the risk of mortality or readmission rates compared with those treated with diuretics.
• When converting torsemide from PO to IV, it is essential to consider the patient's individual response to diuretic therapy and adjust the dose accordingly, as higher doses may be associated with worse clinical outcomes 2.