Losartan

What is Losartan used for?

Losartan is an angiotensin II receptor blocker (ARB). It blocks the action of angiotensin II, a substance that constricts blood vessels, allowing vessels to relax and lowering blood pressure. It also helps protect kidney function in people with diabetes and is used in some patients with heart failure.

How to take Losartan and adjust the dose

Typical adult starting dose is 25mg or 50mg once daily, which a doctor may increase to 100mg once daily based on blood pressure response; some patients may be prescribed a twice-daily split dose. May be taken with or without food. Full blood-pressure-lowering effect may take 2-6 weeks to develop — do not adjust the dose yourself or stop suddenly. This is general guidance; actual dosing must follow your doctor's prescription, especially with liver/kidney impairment or other blood pressure medications.

Losartan side effects

• Common: dizziness, headache (usually resolves after a week), back pain, nasal congestion, upper respiratory infection symptoms, fatigue
• Serious (less common): high blood potassium, kidney impairment, severe allergic reaction, low blood pressure (especially with dehydration or diuretics)

Who should not take Losartan?

• Known allergy to losartan
• Pregnancy (especially mid-to-late pregnancy — can cause fetal injury or death; stop immediately and tell your doctor if you become pregnant)
• Avoid during breastfeeding and for 2 days after the last dose
• Diabetics should not combine with aliskiren-containing blood pressure medicines
• Severe hepatic impairment
• Higher risk of severe hypotension in dehydrated or volume-depleted patients