What is the Difference Between Telmisartan and Amlodipine

The key difference between telmisartan and amlodipine is that telmisartan lowers arterial blood pressure by acting as a reversible antagonist in the angiotensin II receptor in the vascular smooth muscle and adrenal gland, while amlodipine lowers the arterial blood pressure by selectively inhibiting the calcium influx into the smooth muscles and cardiac muscles through dihydropyridine calcium channels.

Hypertension is generally considered a silent killer because its asymptomatic nature leads to cardiovascular diseases, such as heart attacks and strokes. However, fortunately, hypertension can be effectively treated with drug classes, including angiotensin receptor blockers and calcium channel blockers. Telmisartan blocks the angiotensin II receptor in vascular smooth muscles and the adrenal gland to lower arterial blood pressure. In contrast, diuretics or calcium channel blockers such as amlodipine reversibly inhibit the calcium influx by inhibiting the dihydropyridine calcium channels to lower arterial blood pressure. Therefore, they are often prescribed as standalone or combination therapy to manage hypertension. However, the choice between telmisartan, amlodipine, or their combination should be decided based on the individual patient factors, and consulting a healthcare professional is crucial for personalized treatment plans.

CONTENTS

1. Overview and Key Difference
2. What is Telmisartan
3. What is Amlodipine
4. Similarities – Telmisartan and Amlodipine
5. Telmisartan vs Amlodipine in Tabular Form
6. Summary – Telmisartan vs Amlodipine

What is Telmisartan?

Telmisartan is primarily prescribed for managing hypertension, diabetic nephropathy, and congestive heart failure because it reversibly antagonizes the angiotensin II receptor. They bind to the angiotensin II receptor in the vascular smooth muscles and adrenal gland with a high affinity, inhibiting the action of angiotensin II and reducing arterial blood pressure. In addition, telmisartan can act as a partial agonist for PPARγ to promote carbohydrate and lipid metabolism. Telmisartan is prescribed alone or as a combined therapy with other antihypertensive medications.

Oral telmisartan is available in the dose range of 20 mg-160 mg once daily dosing. After the absorption, telmisartan is highly bound with plasma proteins such as albumin and alpha 1-acid glycoprotein. The drug is not generally metabolized in the liver. The only known conjugated form is the pharmacologically inactive acyl-glucuronide, and most administered doses are mainly excreted as unchanged in faeces through the hepatic biliary system.

What is Amlodipine?

Amlodipine is a peripheral arterial vasodilator primarily prescribed to treat hypertension and angina. They are highly selective in dihydropyridine calcium channels and possess a strong affinity with the plasma membrane that ultimately inhibits the calcium ion influx into smooth muscles and cardiac muscles. Furthermore, amlodipine is a powerful antioxidant that produces vasodilators such as nitric oxide to decrease blood pressure. Amlodipine is used alone or combined with other antihypertensive medications to treat hypertension. Amlodipine is also known to relieve chest pain associated with angina by decreasing anginal attack frequency.

Amlodipine is slowly but completely absorbed from the gastrointestinal tract, with a peak plasma concentration 6-12 hours after oral administration. Most absorbed drugs are bound with plasma proteins and heavily metabolized into inactive metabolites in the liver. Amlodipine is primarily excreted from renal clearance.

What are the Similarities Between Telmisartan and Amlodipine?

• Telmisartan and amlodipine effectively reduce blood pressure by relaxing and widening blood vessels.
• They can be prescribed as a fixed-dose combination therapy for individuals who require more than one medication to achieve adequate blood pressure control.
• Both telmisartan and amlodipine contain additional cardiovascular benefits beyond their blood pressure-lowering effects.

What is the Difference Between Telmisartan and Amlodipine?

Telmisartan and amlodipine are generally prescribed to treat hypertension and prevent cardiovascular disease risk. However, there is a distinct difference between telmisartan and amlodipine, as these drugs belong to two different drug classes with distinct properties. Telmisartan is an angiotensin receptor blocker that antagonizes the angiotensin II receptor in the vascular smooth muscles and adrenal gland to lower arterial blood pressure. In contrast,  amlodipine lowers arterial blood pressure by inhibiting the calcium influx into the smooth and cardiac muscles. Nevertheless, both drugs are primarily prescribed for managing hypertension; telmisartan is also prescribed to treat diabetic nephropathy and congestive heart failure, while amlodipine is prescribed to treat other cardiovascular conditions such as angina.

Telmisartan promotes carbohydrate and lipid metabolism by agonizing PPARγ, but amlodipine produces nitric oxide, which can also be owing to antihypertension activities. Telmisartan is not extensively metabolized in the liver and is excreted through the hepatic biliary system with feces. In contrast, amlodipine is extensively metabolized in the liver and excreted with urine through renal clearance.

Below is a summary of the difference between telmisartan and amlodipine in tabular form for side-by-side comparison.

Summary – Telmisartan vs Amlodipine

It is essential to manage hypertension to prevent cardiovascular disease. Angiotensin receptor blockers, including telmisartan and vasodilators such as amlodipine, are commonly used to treat hypertension. Both these drugs effectively manage hypertension through different mechanisms of action that lower arterial blood pressure. Telmisartan is primarily prescribed for hypertension and congestive heart failure; it can also treat diabetic nephropathy. Telmisartan is minimally metabolized in the liver and is primarily excreted with feces. In contrast, amlodipine is extensively metabolized in the liver and primarily excreted with urine. Side effects of telmisartan include dizziness and headache, while amlodipine may cause edema and flushing. This difference between telmisartan and amlodipine should be considered when selecting the appropriate treatment regimen for patients.

Reference:

1. Bakheit, Ahmed H.H., et al. “Telmisartan.” Profiles of Drug Substances, Excipients and Related Methodology, 2015, pp. 371–429.
2. Lin, Angela E., et al. “Clonazepam Use in Pregnancy and the Risk of Malformations.” Birth Defects Research Part A: Clinical and Molecular Teratology, vol. 70, no. 8, 2004, pp. 534–536.

Image Courtesy:

1. “Telmisartan” By Klever – Own work (Public Domain) via Commons Wikimedia
2. “Amlodipine” By DoSiDo – Own work (Public Domain) via Commons Wikimedia