Pharmacology · Angiotensin II receptor blockers (ARBs)
Telmisartan !
A long-acting ARB cleared in bile. Used for high blood pressure and to lower cardiovascular risk in people who cannot take an ACE inhibitor.
Updated 2026-11-01
The figure shows olmesartan, another ARB, in the same binding pocket of the human AT1 receptor; no structure with telmisartan bound is available.
Mechanism of action
Telmisartan blocks the AT1 receptor, so angiotensin II cannot constrict arterioles or release aldosterone. Blood pressure falls and sodium retention lessens, without bradykinin build-up. Its long half-life keeps the effect through the whole day.
- Telmisartan blocks the AT1 receptor
- Arterioles dilate and aldosterone falls
- Blood pressure stays lower through the day
Pharmacokinetics
- Absorption
- Bioavailability depends on the dose; food lowers it slightly
- Elimination
- Mostly by biliary excretion, so biliary obstruction or liver failure raise its levels
- Half-life
- Terminal half-life about 24 hours
Indications
- High blood pressure Arterial hypertension →
- Cardiovascular risk reduction in high-risk patients who cannot take ACE inhibitors Myocardial Infarction (Heart Attack) →
Adverse effects
Common
- Dizziness
- Back pain
- Sinusitis
- Diarrhoea
- Hyperkalaemia
Contraindications
- Pregnancy
- Hypersensitivity to the drug
- Use with aliskiren in people with diabetes
Key interactions
- Potassium-sparing diuretics, potassium supplements or salt substitutes
- Hyperkalaemia
- NSAIDs, including COX-2 inhibitors
- Weaker effect and risk of kidney injury
- Lithium
- Higher lithium levels and toxicity
- Digoxin
- Higher digoxin levels; digoxin is monitored
- Ramipril or another ACE inhibitor
- Dual blockade: more kidney injury and hyperkalaemia without more benefit
What is monitored
- Blood pressure
- Potassium and creatinine
- Digoxin level if combined
Administration and safety
- Given by mouth once a day
- Several «-sartan» names look alike: the name is checked on every order
Nursing care
- Check blood pressure, potassium and creatinine when starting and after changes
- Watch for dizziness, especially in patients on diuretics
- Ask women of childbearing age about pregnancy plans
- Teach the patient that face, lip or tongue swelling is an emergency
Pregnancy and breastfeeding
Contraindicated: drugs acting on the renin-angiotensin system can injure and kill the developing fetus; it is stopped as soon as pregnancy is detected.
Test yourself
Think of the answer, then tap the question to see it.
How is telmisartan mainly eliminated?
By biliary excretion, so biliary obstruction or liver failure raise its levels.
For which patients is telmisartan used to lower cardiovascular risk?
High-risk patients who cannot take an ACE inhibitor.
Which cardiac drug's level rises with telmisartan?
Digoxin, so its level is monitored.
Related drugs
Related conditions
← Back to the class: Angiotensin II receptor blockers (ARBs)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - TELMISARTAN tablet (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.