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Losartan

Prescription

Angiotensin II receptor blocker (ARB)

Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team

Species

Dog

Brands

3 available

Interactions

2 documented

Formulations

Mechanism of action

Selectively blocks angiotensin II AT1 receptors, reducing vasoconstriction, aldosterone release, and blood pressure; provides renoprotective effects

At a glance

Class

Angiotensin II receptor blocker (ARB)

Schedule

Prescription

Storage

Store below 25°C, protect from moisture

Dosing

🐕

Dog

Proteinuria / Hypertension (ACE inhibitor alternative)

Dose

0.125–0.5 mg/kg

Route

Frequency

SID to BID

Max dose

25 mg/dose; 50 mg/day

Duration: Long-term

Educational reference only

This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Tablet — 2

Strength

25mg

Available in India

Strength

50mg

Available in India

Storage

Store below 25°C, protect from moisture

Safety

Absolute contraindications — do not use

Known hypersensitivity

Use with caution

Concurrent ACE inhibitor use
Increased hypotension and hyperkalemia risk

Adverse effects

Common

Mild hypotension

Inappetence

Serious

Hyperkalemia

Acute renal injury

Monitoring parameters

Blood pressureBUN/CreatinineSerum potassium

Educational reference only

Interactions

Major — 2

Benazepril

major

Dual RAAS blockade (ARB + ACE inhibitor) increases risk of hyperkalemia, hypotension, and acute kidney injury

Management: Generally avoid. If combined for refractory proteinuria, monitor renal values and potassium closely.

Spironolactone

major

Both cause potassium retention; combined use significantly increases hyperkalemia risk

Management: Monitor serum potassium frequently. Consider alternative diuretic if ARB is required.

Educational reference only

Brands

International

Cozaar

MSD

India

Losar

Unichem

Losacar

Cadila

FAQs

Frequently asked questions

›What is Losartan?

Losartan is a angiotensin ii receptor blocker (arb) used in pets. Selectively blocks angiotensin II AT1 receptors, reducing vasoconstriction, aldosterone release, and blood pressure; provides renoprotective effects

›What is Losartan used for in pets?

Losartan is used in veterinary medicine for: Proteinuria / Hypertension (ACE inhibitor alternative).

›What is the Losartan dose for dogs?

For dogs, Losartan is typically dosed as follows — Proteinuria / Hypertension (ACE inhibitor alternative): 0.125–0.5 mg/kg PO SID to BID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What are the side effects of Losartan?

Common: Mild hypotension, Inappetence. Serious (call your vet immediately): Hyperkalemia, Acute renal injury.

›Does Losartan need a prescription?

Yes. Losartan is a prescription medication and should only be administered under veterinary supervision.

›When should Losartan not be used?

Do not use Losartan if: Known hypersensitivity.

Educational reference only