Losartan Dosing Guidelines
For hypertension, start losartan at 50 mg once daily and titrate to 100 mg once daily if blood pressure remains ≥140/90 mmHg after 2–4 weeks; for heart failure with reduced ejection fraction, the target dose is 100–150 mg daily; for diabetic nephropathy, the target dose is 100 mg once daily. 1, 2
Adult Dosing by Indication
Hypertension
- Initial dose: 50 mg once daily 1
- Titration: Increase to 100 mg once daily after 2–4 weeks if blood pressure remains ≥140/90 mmHg 1, 2
- Maximum dose: 100 mg once daily 1, 3
- Volume-depleted patients: Start at 25 mg once daily 1
- Combination therapy: Add hydrochlorothiazide 12.5–25 mg daily if blood pressure remains uncontrolled on losartan 100 mg 2, 1
Heart Failure with Reduced Ejection Fraction
- Starting dose: 50 mg once daily 2
- Target dose: 100–150 mg once daily 2
- Titration schedule: Adjust dose every 2 weeks to reach target or maximally tolerated dose 2
- Evidence: The HEAAL trial demonstrated that 150 mg daily was superior to 50 mg daily, with a 10% relative risk reduction in death or heart failure hospitalization (P=0.027) 2
Hypertension with Left Ventricular Hypertrophy
- Starting dose: 50 mg once daily 1
- Escalation: Add hydrochlorothiazide 12.5 mg daily and/or increase losartan to 100 mg once daily, followed by increasing hydrochlorothiazide to 25 mg once daily based on blood pressure response 1
Diabetic Nephropathy (Type 2 Diabetes)
- Starting dose: 50 mg once daily 1
- Target dose: 100 mg once daily 1, 2
- Evidence: The RENAAL trial showed losartan 100 mg daily reduced the primary composite renal outcome by 20% (P=0.01) and lowered the risk of doubling serum creatinine by 28% (P=0.002) 2
- Optimal dose: Studies in type 1 diabetic nephropathy demonstrate that 100 mg daily is significantly more effective than 50 mg daily in reducing albuminuria (48% vs 30% reduction, P<0.01), with no additional benefit at 150 mg 4
Pediatric Dosing (Ages 6–16 Years)
- Starting dose: 0.7 mg/kg once daily (maximum 50 mg total) 1
- Maximum dose: 1.4 mg/kg once daily (not to exceed 100 mg daily) 1
- Contraindication: Not recommended in children <6 years or with eGFR <30 mL/min/1.73 m² 1
Special Populations
Hepatic Impairment
- Mild-to-moderate impairment: Start at 25 mg once daily 1
- Rationale: Plasma concentrations of losartan are approximately 5-fold higher in patients with hepatic impairment 1
- Severe impairment: Losartan has not been studied and should be avoided 1
Renal Impairment
- No dose adjustment required in patients with renal impairment unless volume depleted 1
- Chronic kidney disease: Losartan can be continued as eGFR declines to <30 mL/min/1.73 m² for cardiovascular benefit 2
- Not removed by hemodialysis 3
Elderly Patients (≥75 Years)
- Initiate at low dose to reduce risk of hypotension and renal insufficiency 2
- Slower titration: Increase dose every 2–4 weeks rather than weekly 2
- Monitor closely for dizziness, falls, and fatigue 2
- No routine dose adjustment required based on age alone 1
Dosing Frequency
- Once-daily dosing: Standard and preferred regimen 1, 2
- Twice-daily dosing: Acceptable alternative; can split 100 mg total daily dose into 50 mg twice daily for more consistent 24-hour coverage 2, 3
- Maximum total daily dose: 100 mg for hypertension; 150 mg for heart failure 1, 2
Monitoring Requirements
Initial Monitoring
- Check serum creatinine/eGFR and potassium within 1–2 weeks after initiation or dose increase 2
- Reassess blood pressure every 2–4 weeks during titration 2
- Target blood pressure: <130/80 mmHg for most adults 2
Ongoing Monitoring
- Annual monitoring of renal function and electrolytes during maintenance therapy 2
- More frequent monitoring (every 1–2 weeks initially) in high-risk patients: chronic kidney disease (eGFR <60 mL/min/1.73 m²), diabetes, heart failure, baseline systolic BP <80 mmHg, or concurrent potassium-sparing diuretics 2
Acceptable Laboratory Changes
- Creatinine increase up to 50% (or up to 3 mg/dL) is acceptable and does not require discontinuation 2
- Potassium up to 5.5 mmol/L is acceptable 2
- Discontinue if: Creatinine increases ≥100% or exceeds 4 mg/dL, or potassium >5.5 mmol/L 2
Critical Safety Considerations
Absolute Contraindications
- Pregnancy: All trimesters—causes serious fetal toxicity (renal dysfunction, oligohydramnios, skull hypoplasia, fetal death) 2
- Combination with ACE inhibitors or direct renin inhibitors (aliskiren): Increases risk of hyperkalemia, syncope, and acute kidney injury 2–3-fold without added cardiovascular benefit 2
- History of angioedema with ARBs 2
- Severe bilateral renal-artery stenosis 2
Drug Interactions
- Potassium supplements or potassium-sparing diuretics: Markedly increases hyperkalemia risk 2
- NSAIDs: May blunt antihypertensive effect and worsen renal function 5, 2
- Lithium: Risk of lithium toxicity; monitor levels 2
Common Pitfalls to Avoid
- Underdosing is widespread: Less than 25% of patients are ever titrated to target doses in clinical practice 2
- Do not combine with ACE inhibitors: The VALIANT trial demonstrated increased adverse outcomes without mortality benefit 2
- Do not stop for mild creatinine elevations: A modest rise of 0.1–0.3 mg/dL reflects hemodynamic changes, not tubular injury 2
- Do not use 50 mg as maintenance dose for heart failure: Higher doses (100–150 mg) provide significantly better outcomes 2, 6
- Ensure adequate titration time: Allow 2–4 weeks between dose increases to assess full effect 2
Switching from Losartan to Alternative ARBs
If switching due to inadequate blood pressure control or adverse effects:
Dose Equivalencies
- Losartan 50 mg once daily → Valsartan 80 mg twice daily (160 mg total) or Candesartan 8 mg once daily 7
- Losartan 100 mg once daily → Valsartan 160 mg twice daily (320 mg total) or Candesartan 16–32 mg once daily 7