What is the recommended dose of Losartan (Angiotensin II receptor antagonist) for adults with hypertension?

Recommended Dosage of Losartan for Adults with Hypertension

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

Initial Dosing and Titration

• Standard starting dose: 50 mg once daily 1, 2
• Lower starting dose: 25 mg once daily for patients with possible intravascular depletion (e.g., those on diuretic therapy) 1
• Maximum FDA-approved dose: 100 mg once daily 1, 2
• Frequency: Once daily dosing is sufficient for most patients due to the long half-life of losartan's active metabolite E3174 (6-9 hours) 3

Dose Adjustment and Monitoring

• After initiating losartan, follow up within 1 month to assess adherence and response to treatment 2
• If blood pressure is not adequately controlled with 50 mg:
  • Increase to 100 mg once daily 1
  • Consider adding a thiazide diuretic if monotherapy is insufficient 2
• For stage 2 hypertension (BP ≥160/100 mmHg), initiation with two antihypertensive agents of different classes is recommended 2

Special Considerations

Hepatic Impairment

• For patients with mild-to-moderate hepatic impairment, start with 25 mg once daily 1
• Losartan has not been studied in patients with severe hepatic impairment 1

Left Ventricular Hypertrophy

• For hypertensive patients with left ventricular hypertrophy:
  • Start with 50 mg once daily
  • Consider adding hydrochlorothiazide 12.5 mg daily and/or increasing losartan to 100 mg once daily based on blood pressure response 1

Efficacy and Safety Profile

• Losartan effectively reduces blood pressure with a favorable safety profile 4, 5
• At 50 mg daily, losartan reduces blood pressure by approximately 7/4 mmHg (systolic/diastolic) 6
• At 100 mg daily, losartan reduces blood pressure by approximately 12/6 mmHg (systolic/diastolic) 6
• Losartan 100 mg has been shown to be significantly more effective than 50 mg in reducing blood pressure 6

Common Pitfalls and Caveats

1. Pregnancy: Losartan is contraindicated during pregnancy due to potential fetal toxicity 3

2. Drug Interactions: While losartan has a favorable drug interaction profile, be aware of potential interactions with:

   • Other renin-angiotensin system blockers (avoid combination with ACE inhibitors) 2
   • Potassium-sparing diuretics (increased risk of hyperkalemia) 2

3. Renal Function: Monitor renal function, especially in patients with bilateral renal artery stenosis 7

4. Combination Therapy: When blood pressure control is not achieved with losartan monotherapy:

   • Adding a thiazide diuretic is often effective 2
   • Avoid combining with ACE inhibitors as this combination is not recommended 2

Losartan is well-tolerated with dizziness being the most commonly reported side effect compared to placebo. It offers the advantage of a low incidence of cough compared to ACE inhibitors, making it a good alternative for patients who develop cough on ACE inhibitor therapy 5.