What is the recommended dosage and medication for a patient requiring an Angiotensin Receptor Blocker (ARB)?

ARB Dosing and Medication Selection

For hypertension, start with losartan 50-100 mg once daily or valsartan 80-160 mg once daily; for heart failure with reduced ejection fraction, initiate valsartan 40 mg twice daily and uptitrate to 160 mg twice daily as tolerated. 1, 2

Hypertension Management

First-Line ARB Selection and Dosing

Primary ARB options with evidence-based dosing: 1

• Losartan: 50-100 mg once or twice daily (maximum 100 mg/day)
• Valsartan: 80-320 mg once daily
• Candesartan: 8-32 mg once daily
• Irbesartan: 150-300 mg once daily
• Telmisartan: 20-80 mg once daily
• Olmesartan: 20-40 mg once daily
• Azilsartan: 40-80 mg once daily

Practical Initiation Strategy

Start with lower doses in volume-depleted patients or those at risk for hypotension: 1, 2

• Begin with losartan 50 mg or valsartan 80 mg once daily for most patients
• For patients requiring greater blood pressure reduction, start with losartan 100 mg or valsartan 160 mg daily 1, 2
• Assess response after 2 weeks; maximal effect typically achieved by 4 weeks 1, 2

Dose escalation approach: 1

• If blood pressure remains uncontrolled after 4 weeks, increase to maximum dose (losartan 100 mg, valsartan 320 mg) 1
• Adding a thiazide diuretic provides greater blood pressure reduction than dose escalation beyond 80 mg 1
• Combination therapy with dihydropyridine calcium channel blockers is highly effective 1

Special Populations

Black patients: 1

• Start with ARB plus dihydropyridine calcium channel blocker or thiazide-like diuretic as initial combination therapy
• ARBs are less effective as monotherapy in Black patients (typically low-renin population) 1

Elderly and frail patients: 3

• Start with lowest available dose
• Titrate slowly with small increments to minimize hypotensive episodes
• Consider split dosing if once-daily target doses are not tolerated 3

Heart Failure with Reduced Ejection Fraction (HFrEF)

Valsartan Dosing Protocol

Initiation and titration schedule: 1, 2

• Starting dose: 40 mg twice daily
• Uptitration: Increase to 80 mg twice daily, then 160 mg twice daily
• Target dose: 160 mg twice daily (320 mg total daily dose)
• Maximum studied dose: 320 mg daily in divided doses 2

Key monitoring parameters: 1, 3

• Reduce concomitant diuretic doses when initiating ARB therapy 2
• Monitor renal function and potassium within 1-2 weeks of initiation 3
• If symptomatic hypotension or renal dysfunction occurs, reduce dose 2

Candesartan Alternative

Evidence-based dosing for heart failure: 1

• Starting dose: 4-8 mg once daily
• Target dose: 32 mg once daily
• Demonstrated mortality and morbidity benefits in CHARM-Added trial 1

ARB Use in Heart Failure Context

When to use ARBs in heart failure: 1

• Class I indication: Alternative to ACE inhibitors in patients intolerant due to cough 1
• Class I/IIa indication: Add-on therapy in patients symptomatic despite optimal ACE inhibitor and beta-blocker therapy (unless also taking aldosterone antagonist) 1
• ARBs reduce cardiovascular death and heart failure hospitalization by 16-24% 1

Post-Myocardial Infarction

Valsartan dosing protocol: 2

• Initiate as early as 12 hours post-MI
• Starting dose: 20 mg twice daily
• Uptitration: Increase to 40 mg twice daily within 7 days
• Target dose: 160 mg twice daily
• May be given with thrombolytics, aspirin, beta-blockers, and statins 2

Critical Safety Considerations

Absolute Contraindications

Do not use ARBs in the following situations: 1

• Pregnancy (all trimesters) - causes fetal toxicity and death 1
• Combination with ACE inhibitors or direct renin inhibitors 1
• History of angioedema with ARBs 1
• Patients with bilateral renal artery stenosis (risk of acute renal failure) 1

Special precaution for ACE inhibitor-induced angioedema: 1

• Wait 6 weeks after discontinuing ACE inhibitor before starting ARB

Monitoring Requirements

Essential laboratory monitoring: 1, 3

• Hyperkalemia risk: Increased in patients with CKD, those on potassium supplements, or potassium-sparing drugs 1
• Renal function: Monitor creatinine, especially in patients with pre-existing renal disease 1
• Check labs at 1-2 weeks after initiation and dose changes 3

Pediatric Hypertension (Ages 6-16)

Weight-based dosing for losartan: 4

• Patients <50 kg: Start 2.5 mg daily; may increase to 25-50 mg daily
• Patients ≥50 kg: Start 5 mg daily; may increase to 50-100 mg daily
• Doses below 0.07 mg/kg do not provide consistent efficacy 4

Valsartan alternative (ages 1-16): 2

• Starting dose: 1 mg/kg once daily (maximum 40 mg)
• Higher starting dose: 2 mg/kg may be considered when greater reduction needed
• Maximum dose: 4 mg/kg once daily (maximum 160 mg daily)

Dosing Frequency Considerations

Once-daily vs. twice-daily administration: 3, 5

• Losartan 50-100 mg twice daily provides larger trough responses than once-daily dosing at same total dose 4
• For patients unable to tolerate once-daily target doses, split into twice-daily administration to achieve total daily target 3
• Valsartan twice-daily dosing is standard for heart failure but once-daily acceptable for hypertension 2
• The total daily dose is more important than dosing frequency for achieving clinical benefits 3

Common Pitfalls to Avoid

Underdosing: 6

• Losartan 50 mg may be suboptimal; 100 mg daily provides superior efficacy
• Failure to uptitrate to target doses reduces mortality and morbidity benefits in heart failure 3

Inappropriate combinations: 1

• Never combine ARBs with ACE inhibitors or direct renin inhibitors (increased hyperkalemia and renal dysfunction risk)

Inadequate monitoring: 1, 3

• Failure to check potassium and creatinine within 1-2 weeks of initiation can miss dangerous hyperkalemia or acute kidney injury