What is the most commonly used Angiotensin (angiotensin) Receptor Blocker (ARB)?

Most Commonly Used Angiotensin Receptor Blocker

Losartan is the most commonly used ARB, as it was the first ARB brought to market and remains among the most frequently prescribed agents in this class. 1

Clinical Context for ARB Selection

While losartan holds the distinction of being the most prescribed ARB due to its historical precedence, the choice of ARB in clinical practice should be guided by the specific indication and evidence-based dosing rather than prescription frequency alone. 2

Evidence-Based ARB Selection by Indication

For heart failure with reduced ejection fraction (HFrEF):

• Candesartan, losartan, and valsartan are the three ARBs with proven mortality and hospitalization benefits in major clinical trials. 2
• Candesartan is recommended as a preferred starting agent, initiated at 4-8 mg once daily and titrated to a target of 32 mg once daily. 3
• Valsartan should be dosed at 20-40 mg twice daily, titrating to 160 mg twice daily. 2
• Losartan requires 25-50 mg once daily initially, with a target of 50-100 mg once daily. 2

For post-myocardial infarction with heart failure or reduced ejection fraction:

• Valsartan demonstrated equivalence to captopril in the VALIANT trial for high-risk post-MI patients. 2

For hypertension:

• All ARBs demonstrate similar efficacy, though newer agents may provide slightly superior blood pressure reduction compared to older agents. 4

Important Dosing Considerations

A critical caveat with losartan: the standard 50 mg dose is likely suboptimal. 1

• Losartan should preferably be prescribed at 100 mg/day to obtain maximal clinical benefits and effective AT1 receptor blockade. 1
• This dosing issue distinguishes losartan from other ARBs where standard doses achieve adequate receptor blockade. 1

Class Effect Principles

All ARBs share the same mechanism and similar safety profiles:

• ARBs produce hyperkalemia through identical mechanisms (blocking angiotensin II, reducing aldosterone secretion), with no meaningful differences between individual agents. 5
• ARBs demonstrate significantly fewer side effects than ACE inhibitors, with tolerability comparable to placebo in most studies. 6
• The risk of adverse effects is determined by patient factors (renal function, diabetes, concurrent medications) rather than ARB selection. 5

Practical Prescribing Algorithm

For patients requiring ARB therapy:

1. If treating HFrEF or post-MI with LV dysfunction: Start candesartan 4-8 mg once daily, valsartan 20-40 mg twice daily, or losartan 50 mg once daily (targeting 100 mg). 2, 3

2. Monitor potassium and renal function within 1-2 weeks after initiation and after each dose increase. 3

3. Titrate to target doses over 2-4 weeks if tolerated: candesartan 32 mg daily, valsartan 160 mg twice daily, or losartan 100 mg daily. 2, 3

4. For hypertension alone: Any ARB is appropriate, with selection based on cost, availability, and dosing convenience. 4

Critical Monitoring Parameters

Baseline and ongoing monitoring requirements:

• Check renal function and electrolytes at baseline, 1-2 weeks after initiation, 1 and 4 weeks after dose increases, then at 1,3, and 6 months, then every 6 months. 3
• Exercise extreme caution in patients with GFR <30 mL/min, as major trials excluded this population. 5
• Avoid triple RAAS blockade (ACE inhibitor + ARB + aldosterone antagonist) due to excessive hyperkalemia risk. 5, 3