Cardiovascular
ARBs
Angiotensin-receptor blockers — Blood-pressure and heart/kidney protective drugs, often used when an ACE inhibitor causes cough — names ending in "-sartan".
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
What it is
ARBs lower blood pressure and protect the heart and kidneys in much the same situations as ACE inhibitors — hypertension, heart failure and diabetic kidney disease. They are frequently chosen for people who cannot tolerate an ACE inhibitor.
How it works
Instead of reducing the production of angiotensin II, ARBs block its receptor, preventing it from constricting blood vessels and retaining salt and water. Because they do not raise bradykinin, they rarely cause the dry cough associated with ACE inhibitors.
In practice
In practice ARBs are the natural switch when an ACE inhibitor is effective but causes a dry cough, since they share the benefits without the bradykinin effect. The same monitoring applies — check renal function and potassium after starting or up-titrating — and they carry the same pregnancy contraindication. Do not combine an ARB with an ACE inhibitor, as the pairing raises the risk of harm without added benefit.
Examples
Practical use
How to take it & use it well
- Take it at the same time each day, with or without food, to keep a steady level in your body.
- If you are starting it, be aware it can lower your blood pressure, so stand up slowly for the first few days to avoid dizziness.
- If you miss a dose, take it when you remember the same day, but skip it if it is nearly time for the next one. Do not double up.
- Do not stop it suddenly without advice, even if you feel well, as your blood pressure may rise again.
- Avoid salt substitutes that contain potassium, as these medicines can raise potassium levels.
- Keep up with the blood tests your doctor arranges to check your kidneys and potassium.
Common uses
- Hypertension
- Heart failure (ACE-inhibitor intolerant)
- Diabetic and proteinuric kidney disease
Monitoring
- Renal function and potassium before and after dose changes
- Blood pressure
Weighing it up
Advantages & disadvantages
Advantages
- They lower blood pressure and protect the heart and kidneys, similar to ACE inhibitors.
- They are a good alternative for people who get a cough with ACE inhibitors, as ARBs rarely cause this.
- They are usually taken once a day.
- They do not affect blood sugar or cause weight gain.
- They are well tolerated by most people and widely used on the NHS.
Disadvantages
- They can raise potassium levels and affect kidney function, so blood tests are needed.
- They can cause dizziness or low blood pressure, especially when starting.
- Like ACE inhibitors, they are not safe in pregnancy.
- Rarely they can cause swelling of the face or throat (angioedema), though less often than ACE inhibitors.
- They do not work instantly and need regular use for full benefit.
Key safety principles
What to watch for
- Avoid in pregnancy and in bilateral renal artery stenosis.
- Risk of hyperkalaemia, especially with renal impairment or potassium-sparing drugs.
- Do not use together with an ACE inhibitor.
Key interactions
What to avoid or check alongside
- Combining them with potassium supplements or potassium-sparing water tablets can push potassium too high.
- Anti-inflammatory painkillers (NSAIDs) can reduce their effect and increase the risk of kidney problems.
- Using them with other blood-pressure-lowering medicines can cause your blood pressure to drop too low.
- Taking them together with an ACE inhibitor is usually avoided as it increases the risk of kidney and potassium problems.
- Salt substitutes containing potassium add to the potassium-raising effect.
- Lithium levels can rise when taken with these drugs, needing monitoring.
Patient & carer advice
- Report swelling of the face or lips, though this is rarer than with ACE inhibitors
- Avoid potassium-based salt substitutes unless advised
- Tell us if you might be pregnant
Use with
Related clinical calculators
Dose and risk decisions for this class often depend on renal function, weight or bleeding/stroke risk. These tools help:
Answers
ARBs: frequently asked questions
How is an ARB different from an ACE inhibitor?
They work in a similar way and have similar benefits, but ARBs very rarely cause the dry cough that some people get with ACE inhibitors, which is why they are often used as an alternative.
How long until it works?
Blood pressure begins to fall within hours, but the full effect on your blood pressure and on the heart or kidneys builds over a few weeks of regular use.
Can I drink alcohol with it?
An occasional drink is usually fine, but alcohol can lower blood pressure further and increase dizziness, so be cautious, especially when you start.
Is it safe in pregnancy?
No. Like ACE inhibitors, ARBs can harm a developing baby and should be stopped before or as soon as pregnancy is confirmed. Discuss alternatives with your doctor.
Can I stop it suddenly?
Do not stop without advice. If you have side effects or concerns, speak to your GP or pharmacist so any change is managed safely.
Authoritative sources
Always verify against the source
This overview is for orientation. For doses, interactions, contra-indications and the full monograph, use:
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