What angiotensin receptor blocker (ARB) would you switch a patient to if they are taking Metoprolol (metoprolol tartrate) extended release once a day?

Angiotensin Receptor Blocker Selection for Patients on Metoprolol Extended Release

For patients taking Metoprolol extended release once daily, losartan is the most appropriate angiotensin receptor blocker (ARB) to add to their regimen, starting at 50 mg once daily and titrating to 100 mg once daily as needed. 1

Rationale for ARB Selection

• Losartan is recommended as a first-line ARB option with a well-established safety profile and once-daily dosing that complements the once-daily dosing of Metoprolol extended release 2, 1
• Losartan's initial dose of 50 mg once daily (with titration to 100 mg if needed) aligns with the goal of achieving at least 50% of target doses for guideline-directed medical therapy in heart failure patients 2
• Losartan has been extensively studied in hypertension and has demonstrated efficacy in reducing cardiovascular events, particularly stroke (25% reduction compared to atenolol) 1
• Losartan has a favorable drug interaction profile and does not have clinically significant interactions with beta-blockers like Metoprolol 3

Dosing Considerations

• Start with losartan 50 mg once daily and monitor blood pressure response 1
• If blood pressure goal is not achieved after 2-4 weeks, increase to 100 mg once daily 1, 4
• For patients with possible intravascular volume depletion, consider starting at 25 mg once daily 1
• Losartan can be administered without regard to meals, making it convenient for patient adherence 3

Alternative ARB Options

• Valsartan could be considered as an alternative, particularly in heart failure patients, with a target dose of 160 mg twice daily 2, 5
• However, valsartan's twice-daily dosing regimen may reduce adherence compared to losartan's once-daily dosing when combined with once-daily Metoprolol 6
• Candesartan (target dose 32 mg once daily) and telmisartan (target dose 80 mg once daily) are other alternatives that offer once-daily dosing 2

Special Considerations

• If the patient has heart failure with reduced ejection fraction (HFrEF), ensure that the Metoprolol formulation is specifically metoprolol succinate extended release (not metoprolol tartrate) 2
• For patients with HFrEF, valsartan may be preferred if ACE inhibitors are not tolerated, with a target dose of 160 mg twice daily 2, 5
• Monitor for hypotension, especially if the patient is already on other antihypertensive medications or diuretics 2
• Check renal function and serum potassium within 1-2 weeks of initiation and periodically thereafter 2

Monitoring and Follow-up

• Assess blood pressure response 2-4 weeks after initiation 2
• Monitor for hypotension, particularly in elderly patients or those on multiple antihypertensive medications 2
• Evaluate renal function and electrolytes within 1-2 weeks of starting therapy 2
• Aim to achieve at least 50% of the target dose (losartan 50 mg daily) for adequate clinical benefit 2

Common Pitfalls to Avoid

• Avoid abrupt discontinuation of Metoprolol extended release when adding an ARB 2
• Do not use ARBs in combination with ACE inhibitors or direct renin inhibitors due to increased risk of adverse effects 2
• Avoid use in pregnancy or in patients planning to become pregnant 2
• Be cautious in patients with severe bilateral renal artery stenosis or advanced kidney disease 2

By selecting losartan as the ARB of choice for patients on Metoprolol extended release, you provide a well-tolerated, once-daily medication that complements the existing therapy while minimizing potential drug interactions and maximizing adherence.