Prescribing Guides
Losartan Prescribing Guide for Indian Clinical Practice
Losartan prescribing reference for Indian clinicians covering ARB pharmacology, uricosuric properties, renal protection and NEET PG high-yield points.
MedNext Editorial Team | 2026-08-01 | 8 min read
Losartan Prescribing Guide for Indian Clinical Practice
Losartan prescribing reference for Indian clinicians covering ARB pharmacology, uricosuric properties, renal protection and NEET PG high-yield points.
Losartan was the first angiotensin II receptor blocker (ARB) and remains widely used in Indian clinical practice for hypertension, diabetic nephropathy, and heart failure. Its unique uricosuric property distinguishes it from other ARBs.
Clinical Pharmacology Overview
Losartan selectively blocks the angiotensin II type 1 (AT1) receptor, preventing the vasoconstrictive, aldosterone-secreting, and growth-promoting effects of angiotensin II. Unlike ACE inhibitors, ARBs do not affect bradykinin metabolism, resulting in a much lower incidence of cough and angioedema.
Pharmacokinetics: Oral bioavailability is approximately 33%. Undergoes significant first-pass metabolism by CYP2C9 and CYP3A4 to an active metabolite (EXP3174) that is 10-40 times more potent than the parent compound. Protein binding is more than 98%. Half-life of losartan is 2 hours; active metabolite half-life is 6-9 hours. Eliminated via bile and urine.
Indian Brand Names
- Losacar (Cadila Healthcare)
- Repace (Sun Pharma)
- Losanorm (Micro Labs)
- Covance (Ranbaxy/Sun Pharma)
- Losar (Unichem)
Approved Indications in Indian Clinical Practice
- Hypertension (monotherapy or combination)
- Diabetic nephropathy with proteinuria in type 2 diabetes
- Heart failure (alternative to ACE inhibitors when ACE inhibitor is not tolerated)
- Reduction of stroke risk in hypertensive patients with left ventricular hypertrophy (LIFE trial)
Dosing in Adults
Hypertension: Start 50 mg once daily. May increase to 100 mg once daily. In volume-depleted patients or hepatic impairment, start at 25 mg.
Diabetic nephropathy: 50 mg once daily, titrate to 100 mg once daily.
Heart failure: Start 12.5-25 mg once daily. Titrate to 50-150 mg once daily as tolerated.
Losartan-hydrochlorothiazide combinations (50/12.5 mg, 100/25 mg) are widely prescribed in India.
Important Drug Interactions
- Potassium-sparing diuretics, potassium supplements: risk of hyperkalaemia
- ACE inhibitors: dual RAAS blockade increases adverse effects -- avoid routine combination
- NSAIDs: reduce antihypertensive effect and increase renal impairment risk
- Lithium: ARBs increase lithium levels
- Rifampicin: CYP inducer, reduces active metabolite formation
- Fluconazole: CYP2C9 inhibitor, reduces conversion to active metabolite
Side Effects and Monitoring
Common: dizziness, hyperkalaemia, fatigue. Generally very well tolerated with a side effect profile similar to placebo in trials.
The key advantage over ACE inhibitors is the absence of dry cough (occurs in up to 10-15% of ACE inhibitor users, especially in South Asian populations).
Serious: angioedema (rare, but can occur even though less common than with ACE inhibitors), hyperkalaemia, acute renal failure (in bilateral renal artery stenosis).
Monitoring: serum potassium and creatinine at baseline, 1-2 weeks after initiation or dose change, then periodically. Blood pressure. Urine protein in diabetic nephropathy.
Special Populations
Pregnancy: Category D (second and third trimesters). All ARBs are contraindicated in pregnancy -- foetotoxicity, oligohydramnios, renal failure, and death. Must be discontinued immediately on confirmation of pregnancy.
Renal impairment: No dose adjustment for renal impairment alone. Monitor potassium closely. Contraindicated in bilateral renal artery stenosis.
Hepatic impairment: Start at 25 mg (reduced conversion to active metabolite). Bioavailability increases in cirrhosis.
Elderly: No specific dose adjustment. Start at standard dose unless volume-depleted.
NEET PG High-Yield Points
- First ARB developed; prototype of the class
- Active metabolite EXP3174 is more potent than parent -- CYP2C9 dependent
- Unique uricosuric effect among ARBs (inhibits URAT1 transporter in PCT)
- RENAAL trial: renoprotective in diabetic nephropathy
- LIFE trial: superior to atenolol for stroke prevention in LVH
- No cough (unlike ACE inhibitors) -- no effect on bradykinin
- Category D in pregnancy -- foetotoxic
- Dual RAAS blockade (ACEI + ARB) is harmful (ONTARGET)
- Hyperkalaemia is the most important metabolic adverse effect
Indian Regulatory Status
Losartan is a Schedule H drug under the Drugs and Cosmetics Act. It is included in the NLEM of India and is price-controlled under DPCO. Available as single-ingredient and in fixed-dose combinations with hydrochlorothiazide and amlodipine. Generic losartan is affordable and widely available across India.
Frequently Asked Questions
What is the advantage of losartan over other ARBs?
Losartan has a unique uricosuric effect (lowers serum uric acid) not shared by other ARBs, making it useful in hypertensive patients with concurrent hyperuricaemia or gout. It was also the first ARB developed and has the most long-term safety data.
Is losartan renoprotective?
Yes. The RENAAL trial demonstrated that losartan reduced the risk of doubling of serum creatinine and end-stage renal disease in type 2 diabetic nephropathy independent of blood pressure lowering. ARBs are first-line for hypertensive patients with diabetic nephropathy.
Can losartan be combined with an ACE inhibitor?
Dual RAAS blockade (ACE inhibitor + ARB) is generally not recommended due to increased risk of hyperkalaemia, renal impairment, and hypotension (ONTARGET trial). This combination should be avoided in routine practice.
What is the role of losartan in heart failure?
Losartan is an alternative to ACE inhibitors in heart failure with reduced ejection fraction for patients who cannot tolerate ACE inhibitors due to cough. The ELITE II trial showed comparable efficacy. Valsartan has stronger heart failure trial data (Val-HeFT).
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