Telmisartan; Uses, Dosage, Side Effects, Interaction, Pregnancy

Telmisartan; Uses, Dosage, Side Effects, Interaction, Pregnancy

Telmisartan is a benzimidazole derivative and a non-peptide angiotensin II receptor antagonist with antihypertensive property. Telmisartan selectively antagonizes angiotensin II binding to the AT1 subtype receptor, located in vascular smooth muscle and adrenal gland. The antagonism results in vasodilation and inhibits the angiotensin II-mediated aldosterone production, which in turn leading to a decrease in sodium and water as well as an increase in potassium excretion leading to a subsequent reduction in blood pressure.

Telmisartan is an angiotensin II receptor blocker used in the therapy of hypertension. Telmisartan is associated with a low rate of transient serum aminotransferase elevations, but has yet to be linked to instances of acute liver injury.

Telmisartan is an angiotensin II receptor antagonist (ARB) used in the management of hypertension. Generally, angiotensin II receptor blockers (ARBs) such as telmisartan bind to the angiotensin II type 1 (AT1) receptors with high affinity, causing inhibition of the action of angiotensin II on vascular smooth muscle, ultimately leading to a reduction in arterial blood pressure.

Mechanism of Action of Telmisartan

Telmisartan interferes with the binding of angiotensin II to the angiotensin II AT1-receptor by binding reversibly and selectively to the receptors in vascular smooth muscle and the adrenal gland. As angiotensin II is a vasoconstrictor, which also stimulates the synthesis and release of aldosterone, blockage of its effects results in decreases in systemic vascular resistance. Telmisartan does not inhibit the angiotensin converting enzyme, other hormone receptors, or ion channels. Studies also suggest that telmisartan is a partial agonist of PPARγ, which is an established target for antidiabetic drugs. This suggests that telmisartan can improve carbohydrate and lipid metabolism, as well as control insulin resistance without causing the side effects that are associated with full PPARγ activators.Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). 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 works by blocking the vasoconstrictor and aldosterone secretory effects of angiotensin II.

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Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). 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. Its action is therefore independent of the pathways for angiotensin II synthesis. There is also an AT2 receptor found in many tissues, but AT2 is not known to be associated with cardiovascular homeostasis. Telmisartan has much greater affinity (>3,000 fold) for the AT1 receptor than for the AT2 receptor. Blockade of the renin-angiotensin system with ACE inhibitors, which inhibit the biosynthesis of angiotensin II from angiotensin I, is widely used in the treatment of hypertension. ACE inhibitors also inhibit the degradation of bradykinin, a reaction also catalyzed by ACE. Because telmisartan does not inhibit ACE (kininase II), it does not affect the response to bradykinin. Whether this difference has clinical relevance is not yet known. Telmisartan does not bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation. Blockade of the angiotensin II receptor inhibits the negative regulatory feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and angiotensin II circulating levels do not overcome the effect of telmisartan on blood pressure.

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Indications of Telmisartan

Therapeutic Indications of Telmisartan

  • Hypertension: Treatment of essential hypertension in adults.
  • Cardiovascular prevention: Reduction of cardiovascular morbidity in adults with:manifest atherothrombotic cardiovascular disease (history of coronary heart disease, stroke, or peripheral arterial disease) or type 2 diabetes mellitus with documented target organ damage
  • Hypertension
  • Treatment of essential hypertension in adults.
  • Cardiovascular prevention
  • Reduction of cardiovascular morbidity in patients with:
i) manifest atherothrombotic cardiovascular disease (history of coronary heart disease, stroke, or peripheral arterial disease) or
ii) type 2 diabetes mellitus with documented target organ damage
Hypertension
  • Treatment of essential hypertension in adults.
  • Cardiovascular prevention
  • Reduction of cardiovascular morbidity in patients with:

i) manifest atherothrombotic cardiovascular disease (history of coronary heart disease, stroke, or peripheral arterial disease) or
ii) type 2 diabetes mellitus with documented target organ damage.

Hypertension
  • Treatment of essential hypertension in adults
  • Cardiovascular prevention
  • Reduction of cardiovascular morbidity in patients with:

i) manifest atherothrombotic cardiovascular disease (history of coronary heart disease, stroke, or peripheral arterial disease) or
ii) type 2 diabetes mellitus with documented target organ damage

Hypertension
  • Treatment of essential hypertension in adults.

Cardiovascular prevention

  • Reduction of cardiovascular morbidity in adults with:manifest atherothrombotic cardiovascular disease (history of coronary heart disease, stroke, or peripheral arterial disease) or type 2 diabeted mellitus with documented target organ damage
HypertensionTreatment of essential hypertension in adults.Cardiovascular preventionReduction of cardiovascular morbidity in patients with:i) manifest atherothrombotic cardiovascular disease (history of coronary heart disease, stroke, or peripheral arterial disease) orii) type 2 diabetes mellitus with documented target organ damage

Contra Indications of Telmisartan

  • Extreme loss of body water
  • High amount of potassium in the blood
  • Renal artery stenosis
  • Abnormally low blood pressure
  • Liver problems
  • Blockage of a bile duct
  • Kidney disease with reduction in kidney function
  • Pregnancy
  • Decreased Blood Volume
  • Second and third trimester of pregnancy
  • Biliary obstructive disorders.
  • Severe hepatic impairment.
  • Hypersensitivity to the active substance or to any of the excipients
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The concomitant use of telmisartan with aliskiren-containing products is contraindicated in patients with diabetes mellitus or renal impairment.

Dosage of Telmisartan

Strengths: 20 mg, 40 mg, 80 mg

  • The typical starting dose is 40 mg, taken by mouth, once per day.
  • The maintenance dose is 20–80 mg, taken by mouth, once per day.

Hypertension

  • Initial dose: 40 mg orally once a day
  • Maintenance dose: 40 to 80 mg orally once a day

Cardiovascular Risk Reduction

  • 80 mg orally once a day

Side Effects of Telmisartan

The most common

Common

Rare

Drug Interactions of Telmisartan

Telmisartan may interact with following drugs, supplyments, & may change the efficacy of drugs

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This is not a complete list of telmisartan drug interactions.  Ask your doctor or pharmacist for more information.

Pregnancy & Lactation of Telmisartan

Pregnancy

Angiotensin II receptor antagonists should not be initiated during pregnancy. Unless continued AIIRA therapy is considered essential, patients planning pregnancy should be changed to alternative antihypertensive treatments which have an established safety profile for use in pregnancy. When pregnancy is diagnosed, treatment with AIIRAs should be stopped immediately, and, if appropriate, alternative therapy should be started

Lactation

It is not known if telmisartan crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using telmisartan.

The safety and effectiveness of using this medication have not been established for children.

References

 

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