Angiotensin II receptor antagonist (ARB)

Losartan potassium

Brand names: Cozaar

Used in: Chronic Kidney Disease Hypertension

Losartan is an angiotensin-II receptor blocker (ARB) used for hypertension, diabetic nephropathy, and heart failure where an ACE inhibitor is not tolerated.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Hypertension • Usual adult dose: 50 mg once daily. (2.1) • Usual pediatric starting dose: 0.7 mg per kg once daily (up to 50 mg). (2.1) Hypertensive Patients with Left Ventricular Hypertrophy • Usual starting dose: 50 mg once daily. (2.2) • Add hydrochlorothiazide 12.5 mg and/or increase losartan potassium to 100 mg followed by an increase to hydrochlorothiazide 25 mg if further blood pressure response is needed. (2.2 , 14.2) Nephropathy in Type 2 Diabetic Patients • Usual dose: 50 mg once daily. (2.3) • Increase dose to 100 mg once daily if further blood pressure response is needed. (2.3) 2.1 Hypertension Adult Hypertension The usual starting dose of losartan potassium tablets is 50 mg …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-10-22. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It selectively blocks the angiotensin-II type-1 receptor, producing vasodilatation and reduced aldosterone effect without the bradykinin-related cough of ACE inhibitors.

Prescribing in practice

Start low and titrate; check renal function and potassium before and after starting or up-titrating.
Avoid in pregnancy and bilateral renal artery stenosis; use caution with potassium-raising drugs and NSAIDs.
Do not routinely combine an ARB with an ACE inhibitor.

Monitoring

Monitor U&E (renal function and potassium) and blood pressure.

Counselling the patient

Report dizziness, especially after the first doses.
Avoid potassium-based salt substitutes; tell your prescriber if you become pregnant or unwell with vomiting or diarrhoea.

Evidence & guidelines

An ARB option for hypertension, diabetic nephropathy and heart failure where ACE inhibitors are unsuitable (NICE NG136/NG106).

Reference: NICE NG136; ESC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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