What is the correct dosing for Losartan (Angiotensin II receptor antagonist) in adults with hypertension or diabetic nephropathy?

Losartan Dosing for Hypertension and Diabetic Nephropathy

For adults with hypertension, the recommended starting dose of losartan is 50 mg once daily, with titration to a maximum dose of 100 mg once daily as needed to control blood pressure. For diabetic nephropathy, the recommended starting dose is 50 mg once daily, with titration to 100 mg once daily based on blood pressure response 1.

Hypertension Dosing Algorithm

Initial Dosing

• Standard starting dose: 50 mg once daily 1
• Reduced starting dose: 25 mg once daily for patients with possible intravascular depletion (e.g., on diuretic therapy) 1
• Hepatic impairment: 25 mg once daily for patients with mild-to-moderate hepatic impairment 1

Dose Titration

• Assess blood pressure response after 2-4 weeks
• If target blood pressure not achieved, increase to maximum dose of 100 mg once daily 1
• For stage 2 hypertension (≥160/100 mmHg), consider initiating with two antihypertensive medications, with losartan as one of the agents 2

Diabetic Nephropathy Dosing

• Starting dose: 50 mg once daily 1
• Target dose: 100 mg once daily 1
• Studies have shown that 100 mg daily is more effective than 50 mg daily for renoprotection in diabetic nephropathy 3

Special Considerations

Heart Failure Patients

• For patients with heart failure and reduced ejection fraction, the target dose of losartan is 100 mg once daily 2
• At minimum, aim to achieve at least 50% of the target dose (50 mg daily) for clinical benefit 2

Renal Impairment

• No dosage adjustment is necessary for various degrees of renal insufficiency 4
• For patients with diabetic nephropathy, losartan 100 mg daily provides optimal renoprotection 3

Combination Therapy

• When used for hypertension with left ventricular hypertrophy, losartan can be combined with hydrochlorothiazide 12.5-25 mg daily 1
• For resistant hypertension, losartan can be part of a multi-drug regimen including a diuretic and other antihypertensive agents 2
• Do not combine losartan with ACE inhibitors or direct renin inhibitors due to increased risk of adverse effects without additional benefit 2

Monitoring

• Monitor blood pressure 2-4 weeks after initiation or dose adjustment
• For patients on losartan, check serum creatinine, estimated glomerular filtration rate, and potassium levels at baseline and at least annually 2
• More frequent monitoring may be needed in patients with chronic kidney disease or those on other medications affecting potassium levels

Common Pitfalls to Avoid

1. Underdosing: Many clinicians use suboptimal doses of losartan (50 mg daily) when 100 mg daily provides greater benefits for both hypertension control and renoprotection 2
2. Inadequate monitoring: Failure to monitor renal function and electrolytes, especially in patients with diabetes or chronic kidney disease
3. Inappropriate combinations: Combining losartan with ACE inhibitors or direct renin inhibitors increases adverse effects without providing additional benefits 2
4. Failure to titrate: Not increasing the dose to 100 mg daily when blood pressure targets are not met with 50 mg daily 1

Losartan's favorable pharmacokinetic profile allows once-daily dosing without regard to food intake, and it does not require dose adjustment for age, sex, or race 4. When properly dosed, losartan effectively reduces blood pressure and provides significant renoprotection in patients with diabetic nephropathy.