Losartan
Generic Name: Losartan Potassium
Uses & Medical Indications
Treatment of hypertension, stroke risk reduction in hypertensive patients with left ventricular hypertrophy, and treatment of diabetic nephropathy with elevated serum creatinine and proteinuria in Type 2 Diabetes.
Hypertension, Diabetic Nephropathy, Left Ventricular Hypertrophy, Heart Failure
Work Mechanism & Pharmacology
Patient Overview of Work Mechanism
Losartan blocks the hormonal docking stations (AT1 receptors) that cause blood vessels to tighten, keeping arteries wide, relaxed, and protected from high pressure.
Clinical Mechanism of Action (MoA)
Selective, competitive non-peptide angiotensin II receptor type 1 (AT1) antagonist. Selectively blocks AT1 receptors in vascular smooth muscle and adrenal cortex, antagonizing angiotensin II-induced vasoconstriction, aldosterone release, and sympathetic outflow.
Dosage & Administration Guidelines
Start with 50 mg orally once daily (or 25 mg if volume-depleted). Range: 25 mg to 100 mg once daily or divided twice daily.
Children ≥6 years: 0.7 mg/kg once daily (max initial 50 mg).
Start with 25 mg once daily in frail elderly.
100 mg once daily.
No initial adjustment required; monitor potassium and creatinine.
Start with 25 mg daily in mild to moderate hepatic impairment.
Side Effects & Safety Warnings
Dizziness, upper respiratory infection, nasal congestion, fatigue, back pain.
Hyperkalemia, acute kidney injury in renal artery stenosis, angioedema (much lower incidence than ACE inhibitors).
Pregnancy, concurrent use with Aliskiren in patients with diabetes.
Fetal Toxicity: Discontinue immediately if pregnancy is confirmed. Can cause fetal renal failure, skull hypoplasia, and oligohydramnios.
Interactions (Drugs, Food & Alcohol)
Potassium supplements, Spironolactone (hyperkalemia), Lithium, NSAIDs (blunted efficacy, acute renal failure).
Can be taken with or without food.
Avoid heavy alcohol; causes compounding vasodilation.
Identified Clinical Drug Interactions for Losartan:
Dual Renin-Angiotensin System Blockade & Renal Failure
Pregnancy & Breastfeeding Safety
Strictly contraindicated in pregnancy.
Not recommended during breastfeeding due to lack of human safety data.
Patient Counseling & Practical Advice
Excellent alternative to Lisinopril if you suffered from an ACE-inhibitor dry cough. Continue taking it every day.
Take as soon as remembered. Do not double doses.
Blood pressure, serum potassium, serum creatinine, eGFR.
Frequently Asked Questions
Related Medicines in Antihypertensive
When to Seek Urgent Medical Attention
Severe syncope, acute facial/throat swelling.
Content for Losartan was synthesized from standardized public health monographs, official pharmacopoeias, and health authorities:
- AHA / ACC — Hypertension Guidelines
The information provided on this website is for educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.