Telmisartan: The 'patron saint' of Hypertension Management

Background

Hypertension, a significant risk factor for cardiovascular diseases such as arrhythmia, stroke, and valvular heart disease, is on the rise globally. In India, the Great India Blood Pressure survey reported 234 million adults with hypertension, with around 98,912 deaths and over 2.5 million disability-adjusted life-years attributed to hypertensive heart disease in 2017. Poor control of hypertension also results in higher healthcare resource utilization and costs.

Introduction

Among angiotensin II receptor blockers (ARBs), telmisartan was reported to be preferred by almost 73% of physicians in India as a first-line agent for managing essential hypertension.

Telmisartan is an ARB with a unique pharmacologic profile, including partial agonistic activity on peroxisome proliferator-activated receptor γ (PPARγ) and the most extended half-life among all ARBs. Some animal studies have shown that telmisartan is more effective in improving metabolic syndrome than other ARBs. For example, in an animal model of metabolic syndrome (rats fed a high sodium and fat diet), telmisartan, but not losartan, improved insulin resistance and reduced plasma insulin and glucose. Telmisartan also improved lipid profile and showed an antihypertensive effect more significantly than losartan. In addition, these effects of telmisartan were reversed by GSK0660, a PPARδ antagonist. In a high fructose-induced model of metabolic syndrome in rats, 5 mg/kg of telmisartan significantly reduced plasma glucose, insulin, cholesterol, and triglycerides, significantly increased HDL, and significantly decreased blood pressure and body mass index (BMI).

Pharmacokinetics

Telmisartan has a very low binding affinity for type 2 of angiotensin II receptors (AT2) (K >10,000 nM) and also a minimal binding to catecholamine, acetylcholine, dopamine, serotonin and histamine. The elimination half-life of telmisartan is very long, about 24 h, and consequently has a long-lasting action and sustained reductions of blood pressure. The lipophilicity of telmisartan is also higher than that of other ARBs that facilitate cell penetration, oral absorption, and tissue distribution. Consequently, it produces a larger volume of distribution (almost 500 L). More than 90% of telmisartan is excreted through faeces, and therefore telmisartan is different from other ARBs that, to varying extents, have renal excretion.

Compared to some other antihypertensive drugs (losartan, valsartan, ramipril, atenolol, and perindopril), telmisartan has shown a superior effect in patients with mild-to-moderate hypertension, especially at the end of the dosing interval. In healthy volunteers, it has been shown that 80 mg of telmisartan blocks the effects of angiotensin II by about 90% at peak plasma concentrations and after 24 h, about 40% of inhibition remains. Telmisartan is considered a first-line drug in the management of hypertension, either as monotherapy or as a combination with other antihypertensive drugs, and with an excellent safety profile. It is also used for the prevention of cardiovascular end-organ damages related to hypertension, including arterial stiffness, left ventricular hypertrophy, and atrial fibrillation.

References

[1] Mohammed Yunus Khan. “Effectiveness of Telmisartan on Blood Pressure Control in Hypertensive Patients in India: A Real-World Retrospective Study from Electronic Medical Records.” Cardiology and Therapy 10 1 (2021): 255–269.

[2] Mohsen Imenshahidi, Hossein Hosseinzadeh, Ali Roohbakhsh . “Effects of telmisartan on metabolic syndrome components: a comprehensive review.” Biomedicine &Pharmacotherapy 171 (2024): Article 116169.

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