Telmisartan (Brand names: Micardis, Pritor, among others) belongs to a group of medicines known as angiotensin II receptor antagonists. Angiotensin II is a substance produced in the body which causes blood vessels to narrow, thus increasing blood pressure. Telmisartan blocks the effect of angiotensin II so that the blood vessels relax, and blood pressure is lowered.
 BRAND NAMES
 MECHANISM OF ACTION
Telmisartan is a member of a family of drugs called angiotensin receptor blockers (ARBs).
Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium.
Telmisartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor in many tissues, such as vascular smooth muscle and the adrenal gland.
Telmisartan has the longest half-life among all ARBs; this leads to a significant and 24-h sustained reduction of blood pressure. 
- Treatment of hypertension (To reduce the risk of cardiovascular events, primarily strokes and myocardial infarctions)
- Cardiovascular risk reduction in patients unable to take ACE inhibitors
- Hypertension: Starting dose is 40 mg once daily with or without food. Dosage range is 20-80 mg once daily.
Most of the antihypertensive effect is apparent within 2 weeks and maximal reduction is generally attained after 4 weeks.
- Cardiovascular Risk Reduction : starting and maintenance dose is 80 mg once daily.
 DOSAGE FORMS AND STRENGTHS
Tablets: 20 mg, 40 mg, 80 mg
- Known hypersensitivity (e.g., anaphylaxis or angioedema) to telmisartan
- Contraindicated in patients with severe hepatic impairment.
- Pregnancy; Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus
- Avoid concomitant use of an ACE inhibitor and angiotensin receptor blocker
- NSAIDs: Caution is advised if non steroidal antiinflammatory drugs NSAIDs are prescribed with angiotensin II receptor antagonists, including telmisartan. (Concomitant use of NSAIDS may result in decreased angiotensin II receptor antagonists effectiveness). In some patients with compromised renal function who are being treated with NSAIDS, the co-administration of angiotensin II receptor antagonists may result in further deterioration of renal function. Cases of acute renal failure, usually reversible, have also been reported.
- Do not co-administer aliskiren with Telmisartan in patients with diabetes
- Drugs that inhibit the renin-angiotensin system can cause hyperkaliemia. Potassium-sparing diuretics and potassium supplements may have an additive effect on potassium retention, resulting in hyperkalemia.
 PREGNANCY AND LACTATION
- Pregnancy Category D (US). Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus, thus Telmisartan should not be used during pregnancy or in women planning to become pregnant and is not advisable to use in breast-feeding mothers. If pregnancy is detected during therapy, Telmisartan should be discontinued as soon as possible.
- Nursing Mothers: Choose to discontinue nursing or drug
 SIDE EFFECTS
Most common are: back pain, sinusitis, diarrhea, hypotension, intermittent claudication and skin ulcer
Serious adverse drug reactions include anaphylactic reaction and angioedema which may occur rarely (≥1/10,000 to <1/1,000) , and acute renal failure.
 RELATED LINKS
|ACE inhibitors||Benazepril (Lotensin) • Captopril (Capoten) • Cilazapril • Delapril • Enalapril (Renitec, Vasotec) • Fosinopril (Monopril) • Lisinopril (Prinivil, Zestril) • Moexipril (Univasc) • Perindopril (Aceon) • Quinapril (Accupril) • Ramipril (Altace, Triatec) • Trandolapril (Mavik) • Zofenopril (Bifril, Zopranol)|
|Angiotensin II receptor antagonist||Azilsartan (Edarbi) • Candesartan (Atacand) • Eprosartan (Teveten) • Irbesartan (Aprovel, Avapro, Karvea) • Losartan (Cozaar) • Olmesartan (Benicar, Olmetec) • Telmisartan (Micadis) • Valsartan (Diovan, Tareg)|
|Renin inhibitors||Aliskiren (Rasilez, Tekturna)|
|Alpha-1 blockers||Doxazosin (Cardura) • Prazosin (Minipress) • Terazosin (Hytrin)|
|Alpha-2 agonists (centrally acting)||Clonidine (Oral route) • Clonidine (Transdermal) (Catapresan) • Guanfacine (Tenex) • Methyldopa (Aldomet)|
|Calcium channel blockers||Dihydropyridines||Amlodipine (Norvasc) • Barnidipine (Vasexten) • Felodipine (Plendil) • Isradipine (Dynacirc) • Lacidipine (Lacipil, Motens) • Lercanidipine (Zanidip) • Manidipine • Nicardipine • Nifedipine (Adalat) • Nisoldipine • Nitrendipine|
|Benzothiazepine||Diltiazem (Cardizem, Taztia XT, Tiazac, Tildiem)|
|Phenylalkylamine||Gallopamil • Verapamil (Calan)|
|Beta blockers||Beta1 selective (cardioselective)||Acebutolol (Sectral) • Atenolol (Tenormin) • Betaxolol (Kerlon) • Bisoprolol (Concor) • Celiprolol (Cordiax) • Metoprolol (Betaloc, Lopressor, Toprol-XL) • Nebivolol (Bystolic, Lobivon, Nebilox)|
|Nonselective (Beta1 and Beta2 blockers)||Oxprenolol (Trasitensin) • Propranolol (Inderal) • Timolol (Blocadren)|
|Nonselective (Beta1, Beta2 and Alpha1 blockers)||Carvedilol (Dilatrend) • Labetalol (Trandate)|
|Beta blocker with intrinsic sympathomimetic activity (ISA)||Acebutolol (Sectral) • Celiprolol (Cordiax)|
|Lipophilic Beta blockers||Propranolol (Inderal) • Metoprolol (Betaloc, Lopressor, Toprol-XL) • Oxprenolol (Trasitensin)|
|Diuretics||Carbonic anhydrase inhibitors||Acetazolamide (Diamox)|
|Loop diuretics||Bumetanide • Etacrynic acid • Furosemide (Lasix) • Piretanide • Torasemide (Demadex)|
|Thiazide diuretics||Chlorothiazide (Diuril) • Hydrochlorothiazide (Esidrex)|
|Thiazide-like diuretics||Chlortalidone (Hygroton) • Indapamide (Lozol, Lozide) • Metolazone|
|Potassium-sparing diuretics|| Epithelial sodium channel blockers: Amiloride (Midamor) • Triamterene (Dyrenium) |
Aldosterone receptor antagonists: Potassium canrenoate • Eplerenone (Inspra) • Spironolactone (Aldactone)
|Combination therapy||Amiloride/Hydrochlorothiazide (Moduretic) • Spironolactone/Hydrochlorothiazide (Aldactazide)|