What is the equivalent dosage of Losartan (Angiotensin II Receptor Antagonist) when converting from Lisinopril (Angiotensin-Converting Enzyme Inhibitor)?

From the Guidelines

When converting from lisinopril to losartan, a typical starting dose of losartan is 50 mg once daily for patients previously taking lisinopril 10-20 mg daily, as indicated by the dose ranges in Table 28 from the study 1. For patients on higher lisinopril doses (30-40 mg), starting with losartan 100 mg daily is appropriate, considering the goal doses should be at the higher end of the dose range when possible, as suggested by the study 1. The conversion should be done as a direct switch without overlap, ideally monitoring blood pressure within 1-2 weeks after the change. Losartan may take 3-6 weeks to reach full effect, so patience is needed when evaluating its efficacy. This conversion is often made because losartan (an angiotensin receptor blocker) typically causes less cough than lisinopril (an ACE inhibitor), while providing similar blood pressure control, which is crucial in managing hypertension in patients with diabetes or chronic kidney disease, as highlighted in the study 1. Some key points to consider when making this conversion include:

• Monitoring renal function and potassium levels after the switch, particularly in patients with kidney disease or those taking potassium supplements or potassium-sparing medications.
• Being aware of common side effects of losartan, such as dizziness, back pain, and occasional diarrhea.
• Continuing to take the medication at the same time each day to maintain consistent blood pressure control.
• Recognizing that higher levels of blood pressure are associated with more rapid progression of kidney disease, as noted in the study 1, making effective blood pressure management critical.

From the Research

Lisinopril to Losartan Conversion

• The conversion from lisinopril to losartan is a common practice in the treatment of hypertension and heart failure, but there is limited direct evidence to guide this conversion 2, 3.
• A study comparing the effectiveness of twice-daily versus once-daily lisinopril and losartan found no significant differences in blood pressure control between the two dosing regimens, but did note an increased risk of angioedema with twice-daily lisinopril 3.
• Another study examined the use of combined therapy with an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II receptor blocker (ARB) for the treatment of proteinuria, and found that the combination of lisinopril and losartan was effective in reducing proteinuria, but emphasized the need for close surveillance of renal function and blood pressure during such therapy 4, 5.
• Losartan has been studied as an alternative to ACE inhibitors in patients with renal dysfunction, and while there is limited evidence to suggest that losartan is better tolerated than ACE inhibitors from the standpoint of renal toxicity, it may be used in patients with underlying renal dysfunction if deemed necessary, with close monitoring of renal function 6.

Key Considerations

• When converting from lisinopril to losartan, it is essential to consider the individual patient's renal function, blood pressure, and proteinuria levels, as well as their overall clinical status 2, 3, 4, 5, 6.
• Close monitoring of renal function and blood pressure is crucial during the conversion process, as both lisinopril and losartan can affect renal function and blood pressure control 3, 4, 5, 6.
• The dosage and dosing regimen of losartan may need to be adjusted based on the individual patient's response to the medication, and the presence of any underlying renal or cardiovascular disease 3, 5, 6.