What ARBs are used for
Angiotensin receptor blockers, or ARBs, are prescription medicines for high blood pressure. Telmisartan is the most widely used one in India; others include losartan, olmesartan, valsartan and irbesartan. Doctors also use them to protect the kidneys in people with diabetes who have protein in the urine, and in heart failure and after heart attacks in selected people.
ARBs are often combined with other BP medicines such as amlodipine or a water tablet like hydrochlorothiazide or chlorthalidone, sometimes in a single tablet. Doctors do this when one medicine alone does not bring BP down to target, and it is always their decision.
- High blood pressure
- Kidney protection in diabetes with protein in the urine
- Heart failure, in selected people
- Reducing heart and stroke risk in high-risk people
How telmisartan and ARBs work
The body makes a hormone called angiotensin II, which tightens blood vessels and makes the kidneys hold on to salt and water. Both effects push blood pressure up. ARBs block angiotensin II from attaching to its receptors, so blood vessels relax, less salt and water are held back, and pressure falls.
Reducing the effect of angiotensin also lowers pressure inside the tiny filters of the kidneys, which helps slow kidney damage in diabetes. ACE inhibitors like ramipril work on the same system in a different way. ARBs are less likely to cause the dry cough that ACE inhibitors sometimes do.
Telmisartan and ARBs side effects: common and serious
Common side effects include dizziness, especially when standing up quickly, tiredness, headache, back pain and mild stomach upset. Dizziness is more likely at the start of treatment or when taken with water tablets. It usually settles within a few days. Getting up slowly from a bed or chair and drinking enough water helps.
Serious side effects include high potassium levels in the blood, which can affect heart rhythm, and a drop in kidney function, particularly in people with narrowed kidney arteries, dehydration or existing kidney disease. Rarely, ARBs cause swelling of the face, lips or tongue, called angioedema, which needs emergency care. Very low blood pressure and fainting can occur in people who are dehydrated.
Who should avoid them or take extra care
ARBs must not be used in pregnancy, as they can seriously harm the baby's kidneys and development, especially in the later months. Women who could become pregnant should discuss contraception or alternative medicines with their doctor, and tell their doctor immediately if they become pregnant. They are generally avoided while breastfeeding as well, unless a doctor advises otherwise.
People with kidney disease, narrowing of the kidney arteries, severe liver disease, high potassium or heart valve narrowing need careful monitoring. Elderly people are more prone to dizziness and kidney changes. ARBs are only on a doctor's prescription; never start or stop them on your own.
Telmisartan and ARBs interactions to know
Potassium supplements, salt substitutes that contain potassium, and potassium-sparing water tablets like spironolactone can raise potassium too high when combined with ARBs. Doctors generally avoid combining an ARB with an ACE inhibitor or aliskiren because of kidney and potassium risks.
Painkillers such as ibuprofen and diclofenac can reduce the BP-lowering effect and, together with ARBs and water tablets, can harm the kidneys, especially during dehydration. ARBs can raise lithium levels. Telmisartan may slightly raise digoxin levels. Always tell your doctor and pharmacist about every medicine and supplement you take.
Practical tips for using telmisartan and ARBs
Take your ARB at the same time every day as prescribed, with or without food. Keep taking it even when you feel well, as high BP rarely causes symptoms. Check your BP regularly and have kidney function and potassium tested as your doctor advises, usually soon after starting and then periodically.
If you have severe vomiting, diarrhoea or cannot drink fluids, especially in hot summer weather, contact your doctor, who may advise pausing the medicine for a short time. Cut down on salt, pickles and packaged foods, stay active, keep a healthy weight, limit alcohol and stop smoking.
When to talk to your doctor about telmisartan and ARBs
See your doctor if you feel dizzy or faint, if your BP stays high, or if you notice less urine or swelling. Seek emergency care for swelling of the face, lips or tongue, chest pain, severe headache, one-sided weakness, or muscle weakness with an irregular heartbeat. Always talk to your doctor or pharmacist before changing BP medicines.
Related medicines
Only your doctor can decide which medicine, dose and combination is right for you.
- Amlodipine (calcium channel blocker)Relaxes blood vessels to lower BP.Only on a doctor's prescription; can cause ankle swelling.
- ACE inhibitors such as ramiprilWork on the same hormone system to lower BP and protect kidneys.Only on a doctor's prescription; may cause dry cough; not combined with ARBs.
- Thiazide-type diuretics such as hydrochlorothiazide or chlorthalidoneRemove extra salt and water to lower BP.Only on a doctor's prescription; salts in the blood need checking.
- Beta-blockers such as metoprololSlow the heart and lower BP.Only on a doctor's prescription; do not stop suddenly.
See a doctor urgently if
- Swelling of the face, lips, tongue or throat, or difficulty breathing
- Fainting or severe dizziness
- Muscle weakness with a slow or irregular heartbeat, which may mean high potassium
- Passing much less urine than usual
- Finding out you are pregnant while taking an ARB (contact your doctor at once)
Tests that may help
This article is general health information, not medical advice. Do not start, stop or combine medicines on your own — always follow your doctor's prescription and ask your pharmacist if unsure.