What is the recommended dosage and treatment guidelines for losartan (Angiotensin II Receptor Blocker) in patients with hypertension?

Losartan Dosage and Treatment Guidelines for Hypertension

The recommended starting dose of losartan for hypertension is 50 mg once daily, with titration up to a maximum dose of 100 mg once daily as needed to achieve blood pressure control. 1

Initial Dosing and Adjustments

• Standard starting dose: 50 mg once daily 1
• Lower starting dose: 25 mg once daily for patients with possible intravascular depletion (e.g., those on diuretic therapy) 1
• Maximum dose: 100 mg once daily 1
• Administration: Can be taken without regard to food 2
• Timing: Once-daily dosing is sufficient due to the active metabolite E3174 having a half-life of 6-9 hours 2

Dose Titration and Monitoring

• Increase dose to 100 mg daily if blood pressure remains uncontrolled on 50 mg 3
• Monitor blood pressure every 2-4 weeks during dose adjustments 3
• Target blood pressure is <140/90 mmHg within 3 months 3
• Check renal function and potassium levels before initiation and periodically during treatment, especially in patients with:
  • Chronic kidney disease
  • Bilateral renal artery stenosis
  • Concomitant use of potassium-sparing diuretics 3

Combination Therapy

If blood pressure remains uncontrolled on maximum losartan dose, add:

1. First-line addition: Calcium channel blocker (e.g., amlodipine 5 mg daily) 3
2. Alternative additions:
   • Thiazide-like diuretic (e.g., hydrochlorothiazide 12.5-25 mg) 3
   • For resistant hypertension: Add spironolactone 25 mg daily (if serum potassium <4.5 mmol/L) 4

Special Populations

Hepatic Impairment

• Mild to moderate impairment: Starting dose of 25 mg once daily 1
• Severe impairment: Not recommended (insufficient data) 1

Renal Impairment

• No initial dosage adjustment necessary for various degrees of renal insufficiency 2
• Not removed during hemodialysis 2

Elderly Patients

• No significant age-related pharmacokinetic changes requiring dose adjustment 2

Black Patients

• May respond better to a combination of ARB + dihydropyridine CCB or ARB + thiazide diuretic 3
• The LIFE study showed less benefit in Black patients compared to other populations 5

Additional Clinical Considerations

• Losartan 100 mg daily has been shown to be more effective than 50 mg daily for renoprotection in diabetic nephropathy without additional benefit at 150 mg 6
• For hypertensive patients with left ventricular hypertrophy, losartan (50-100 mg) has demonstrated superior stroke risk reduction compared to atenolol 7, 5
• Losartan is generally well-tolerated with a favorable side effect profile compared to other antihypertensives 2, 8
• Avoid use during pregnancy, especially in the second and third trimesters, due to risk of fetal toxicity 2

Cautions and Contraindications

• Avoid combining ACE inhibitors, ARBs, and aldosterone antagonists together as this combination is potentially harmful for patients with heart failure with reduced ejection fraction 4
• Contraindicated in pregnancy 2
• Use with caution in patients with bilateral renal artery stenosis 3

Losartan's favorable pharmacokinetic profile, once-daily dosing, and good tolerability make it an excellent choice for hypertension management, with demonstrated benefits beyond blood pressure reduction, particularly in patients with left ventricular hypertrophy or diabetic nephropathy.