Losartan – ARB for blood pressure control and cardiovascular protection.
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What is Losartan?
Losartan is a well-tolerated ARB that provides effective blood pressure control and cardiovascular protection, particularly valuable for patients who cannot tolerate ACE inhibitors. Its additional benefits for kidney protection make it especially useful for diabetic patients.
Book an online consultation if you have high blood pressure, diabetes with kidney concerns, heart failure, or need cardiovascular protection. Our GPs can assess your blood pressure control needs and determine if Losartan or other cardiovascular medications are appropriate for your specific health profile.
What is Losartan used for?
- High blood pressure (hypertension)
- Heart failure
- Diabetic nephropathy (kidney protection)
- Post-stroke prevention
- Cardiovascular disease prevention
- Chronic kidney disease protection
- Left ventricular hypertrophy reduction
How does Losartan work?
An angiotensin receptor blocker (ARB) that blocks angiotensin II receptors, preventing vasoconstriction and aldosterone release, leading to blood vessel dilation and reduced blood pressure.
Dosage and Administration
Adults
Starting dose 25-50mg once daily, may be increased to 100mg daily. For heart failure: start with 12.5mg daily.
Children
Weight-based dosing for hypertension—specialist supervision required.
Important Notes
- Can be taken with or without food.
- Take at the same time each day for consistent blood pressure control.
- Do not stop suddenly without consulting your GP.
- Regular blood pressure and kidney function monitoring required.
Side Effects
Common Side Effects
- Dizziness (especially when standing)
- Headache
- Fatigue
- Upper respiratory tract infections
- Back pain
- Diarrhoea
Serious Side Effects
Seek immediate medical attention if you experience:
- Severe low blood pressure (hypotension)
- Kidney problems (acute kidney injury)
- High potassium levels (hyperkalaemia)
- Severe allergic reactions (angioedema)
- Liver problems (rare)
Important Warnings
- Tell your GP if you have kidney disease, liver problems, or heart valve disease.
- May cause dizziness—rise slowly from sitting or lying positions.
- Regular monitoring of kidney function and potassium levels required.
- Not suitable during pregnancy—can harm the developing baby.
- May interact with potassium supplements and salt substitutes.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- ACE inhibitors—avoid combination due to increased kidney problems.
- Potassium supplements—may cause dangerous high potassium levels.
- NSAIDs—may reduce effectiveness and increase kidney problems.
- Diuretics—may enhance blood pressure lowering but monitor kidney function.
- Lithium—may increase lithium levels.
- Salt substitutes containing potassium—avoid or use with caution.
Frequently Asked Questions
How is Losartan different from ACE inhibitors like Ramipril?
Losartan blocks angiotensin receptors rather than ACE enzymes, providing similar benefits but typically with fewer side effects, particularly less dry cough.
Why might my GP choose Losartan over an ACE inhibitor?
Losartan may be chosen if you develop a dry cough with ACE inhibitors, or if you need similar cardiovascular protection with better tolerability.
Can Losartan protect my kidneys if I have diabetes?
Yes, Losartan provides specific kidney protection in diabetic nephropathy, slowing the progression of kidney disease and reducing protein in urine.
How long does it take to work?
Blood pressure reduction typically begins within 1 week, with maximum effects usually seen after 4-6 weeks of treatment.
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14