Heart attack or congestive heart failure is the leading cause of death in today’s world. Various drugs are classified to treat cardiovascular diseases. One such classification is calcium channel blockers, which include amlodipine. These drugs lower the heart rate and help treat heart diseases.

1- Introduction

As per the classification, amlodipine is a calcium channel blocker used to lower blood pressure and heart rate, decreasing the risk of cardiovascular diseases. Along with amlodipine, various other drugs are also used to treat cardiovascular disease, but they differ in their mechanism of action. The mechanisms of various drugs will be discussed further in the article.

2- What are Cardiovascular Diseases?

Cardiovascular or CV diseases are a class of diseases that include the heart or blood vessels. They are one of the most common diseases worldwide. Based on their origin or root cause, they are classified into various types.

2.1- Types of Cardiovascular Diseases-

 Some common types of CV diseases are-

2.1.1- Coronary Artery Disease (CAD)-

It is also called Ischemic heart disease when the blood vessels of heart muscles become narrowed or blocked due to the deposition of cholesterol or other fatty substances. It causes angina (chest pain) or heart attack.

2.1.2- Stroke-

It occurs when enough blood can’t reach the brain cells, leading to various neurological impairments. It occurs due to blockage or bleeding (haemorrhage).

2.1.3- Hypertension-

It is also called high blood pressure, the blood pressure is persistently elevated above the normal level and due to this arteries are damage over time which increases the risk of other diseases like CAD, stroke and other cardiovascular diseases.

2.1.4- Arrhythmias-

This is called irregular heartbeat, affecting the heart’s ability to pump blood efficiently. It can be too fast (tachycardia), slow (bradycardia) or irregular.

2.1.5- Heart Failure-

This condition occurs when the heart cannot pump blood efficiently to the body’s organs, hence the functioning of various organs is disrupted.

2.1.6- Valve Heart Disease-

It is associated with the problem in heart valves that control the blood flow within the heart.

2.1.7- Cardiomyopathy-

This disease affects the heart muscles and brings structural and functional changes to it. 

2.2- Causes of Cardiovascular Diseases-

It can occur due to various factors and a combination of risk factors. Some of the known causes are-

· Chronic stress can lead to bad lifestyle behaviors, including overeating, smoking, and a lack of physical activity, all of which increase the risk of cardiovascular disease.

· A family history of cardiovascular disease can raise an individual’s risk. Genetic factors like high blood pressure, high cholesterol, and cardiac disorders may impact illnesses.

· Individuals with diabetes are more likely to acquire cardiovascular illnesses. High blood sugar levels can damage blood vessels over time, causing atherosclerosis and other complications.

· Elevated LDL (low-density lipoprotein) cholesterol, also known as “bad” cholesterol, can lead to plaque formation in the arteries. This can lead to atherosclerosis, which decreases blood flow and increases heart disease risk.

· Being overweight or obese increases your risk of developing cardiovascular disease. Excess body weight can lead to illnesses including high blood pressure, high cholesterol, and diabetes, all of which raise the risk of heart disease. Tobacco smoke contains chemicals that can damage blood vessels and heart tissue, resulting in the development of atherosclerosis (artery constriction) and other cardiovascular disorders. Smoking is a significant risk factor for heart disease and stroke.

· Lack of regular physical activity is a significant risk factor for cardiovascular disease. Physical inactivity correlates to obesity, high blood pressure, and other disorders that raise the risk of heart disease.

2.3- Symptoms of Cardiovascular Diseases-

Some of the common symptoms of cardiovascular diseases associated with different types of diseases are-

·        Heart palpitations.

·        Sweating.

·        Lightheadedness.

·        Shortness of breath.

·        Chest pain or pressure or heaviness in the chest.

·        Neck Pain.

·        Heart Burn.

·        Swelling in lower body.

·        Insomnia.

·        Fatigue.

3- Common Types of Drugs Used to Treat Cardiovascular Diseases-

Some of the variety of drugs are-

3.1- ACE Inhibitor-

ACE, or angiotensin-converting enzyme inhibitor, works on the pathway of the physiological regulation of electrolyte balance, prevents vasoconstriction of blood vessels and causes vasodilation, which leads to lower blood pressure and heart rate.

3.2- Angiotensin receptor blockers-

Angiotensin receptor blockers also work on the pathway of the physiological regulation of electrolyte balance, causing vasodilation and lowering the heart rate.

 Example: Losartan

3.3- Calcium Channel Blockers-

Calcium channel blockers blocks the calcium channel of the myocardial muscles and prevents its constriction, so causes dilation of the blood vessels which leads to a lower heart rate.

Example: Amlodipine

3.4- Diuretics-

Diuretics causes excretion of water and sodium from the body and plasma volume decreases, hence blood pressure decreases which lowers the heart rate.

Example: Furosemide

3.5- Vasodilators-

Vasodilators are the type of medication given to dilate the blood vessels, which decreases the blood pressure and heart rate.

Example: Sodium nitroprusside.

These are only a few of the drugs used to treat various heart diseases; there are many more besides the above-given ones. The main type, which will be discussed further, is a calcium channel blocker, as amlodipine belongs to this class.

4- How Does a Calcium Channel Blocker Work?

Calcium channel blockers work by blocking or lowering calcium entrance through voltage-gated channels, which causes various physiological effects, most notably on the cardiovascular system.

1. Calcium channel blockers prevent calcium entry by blocking L-type calcium channels in the cell membrane. These channels allow calcium ions to enter the cell in response to membrane depolarization.

2. Calcium Channel Blockers (CCBs) limit calcium influx by inhibiting these channels. This is especially significant in cardiac and smooth muscle cells because calcium influx is required for muscle contraction.

3. CCBs slow the heart rate (negative chronotropic action) by blocking calcium entrance into the sinoatrial (SA) node cells, which generate the heart’s electrical impulses.

4. CCBs reduce the force of contraction (negative inotropic effect) by altering calcium availability in cardiac cells.

5. Calcium channel blockers promote vasodilation in arterial smooth muscle cells by preventing calcium entrance. This relaxes the blood arteries, reduces peripheral resistance, and lowers blood pressure.

6. CCBs can also influence smooth muscle cells in various organs, including the coronary arteries, peripheral arteries, and bronchi. This causes smooth muscular relaxation as well as vasodilation.

5- Does Amlodipine Lowers Heart Rate-

Amlodipine is a calcium channel blocker that primarily inhibits the inflow of calcium ions into vascular smooth muscle cells and cardiac muscle cells. Although it is not known to lower heart rate directly, it does so indirectly through its effects on blood pressure and vascular tone.

It is crucial to note that while amlodipine may indirectly affect heart rate due to its effects on blood pressure and vascular tone, it is not regarded as a major medicine for decreasing heart rate. Beta-blockers are medications explicitly created to lower heart rate. They work by blocking the effects of adrenaline on the heart, slowing it down and diminishing its force of contraction.

6- Side Effects of Amlodipine-

Amlodipine alone or together with other medications are used to treat high blood pressure or hypertension. As it affects the heart muscles, arteries and veins, its long-term use may affect them badly. Its various side effects are-

·        Swelling of ankles and feet.

·        Difficulty in breathing.

·        Dizziness.

·        Fast or irregular heartbeat.

·        Redness of face, arms, neck and sometimes upper chest areas.

·        Nausea.

·        Constipation.

·        Stomach pain.

·        Confusion

·        Redness, soreness or itching of skin.

·        Sweating.

·        Weakness in arms, hands, legs or feet.

·        Weight gain.

7- Synergism of Amlodipine for Lowering Heart Rate-

Synergism or synergistic effect is an effect shown when two or more drugs interact with each other that causes the total effect of the drugs to be greater than the individual effect of the one drug. Amlodipine also shows a synergistic reaction with the medicines that are used to lower the heart rate, like-

7.1- Combining amlodipine and telmisartan (2+4 and 1+4 mg/kg) and amlodipine and candesartan (0.5+4 and 2+1 mg/kg) may provide optimal synergy against hypertension.

7.2- A Combination of Atenolol and Amlodipine is used for lowering and stabilizing blood pressure.

7.3- Combination of Amlodipine with Atorvastatin shows a synergistic effect. This combination medication can be used to treat cardiovascular conditions, particularly coronary artery disease, by protecting low-density lipoproteins and vascular cell membranes from oxidative damage.

7.4- A Combination of Amlodipine and Zofenopril (ACE inhibitor) is used for the treatment of hypertensive patients.

7.5- The Combination of Nicorandil and Amlodipine has a synergistic protective impact on tissue defence and lipid metabolism after myocardial infarction.

8- Scientific Production of Amlodipine-

The scientific production of amlodipine or any drug goes through various steps; those steps are-

8.1- Discovery & Research-

This is a function of the research and development industry. Scientists and pharmaceutical researchers study chemicals to discover possible candidates for new medications.

8.2- Pre-clinical Development-

After identification, amlodipine goes through preclinical development, which involves laboratory studies and testing for potential safety and efficacy.

8.3- Clinical Trials-

After completing the preclinical studies, amlodipine enters the clinical trials phase. It involves testing the drugs on human subjects to evaluate their safety, efficacy, dosage and adverse effects. It constitutes a of total four phases (I, II, III & IV).

8.4- Regulatory Approval-

After the successful completion of clinical trials, the application for the approval of amlodipine is submitted to regulatory agencies like the Food and Drug Administration (FDA). If all the criteria are fulfilled, the agency approves.

8.5- Manufacturing-

Once regulatory permission is secured, the medicine, in this example, amlodipine, enters commercial manufacture. Large-scale manufacturing facilities create medicine using tight quality control criteria.

8.6- Quality Assurance-

When the final product is obtained, the quality assurance team will monitor the product for any type of defects. If any defect is found, the product is returned to the company for improvement.

8.7- Distribution & Marketing-

Amlodipine is produced and delivered to pharmacies, hospitals, and healthcare professionals for prescription and dispensing purposes. The pharmaceutical business promotes medicine to healthcare professionals to enhance their knowledge of its advantages and applications.

9- Other Classes of Drugs used to Lower the Heart Rate-

Various drugs other than amlodipine (calcium channel blocker) also lower heart rate. Some of the classes are-

9.1- Beta- Blockers-

Beta-blockers block the effect of adrenaline and reduce the heart rate and blood pressure.

It includes Metoprolol, Atenolol and Propranolol.

9.2- Digoxin-

Digoxin increase the strength of myocardial muscle contractions and slow down heart rate.  

It includes digoxin and digitoxin.

9.3- Antiarrhythmics-

Antiarrhythmics are used to treat irregular heartbeats, and can also have the effect of lowering the heart rate.

It includes Amiodarone, Propafenone.

9.4- Ivabradine-

Ivabradine selectively targets the heart’s pacemaker cells in order to lower heart rate while leaving other elements of cardiac function unaffected.

9.5- Adenosine-

Adenosine is used in emergencies to rapidly reduce the heart rate, especially in cases of supraventricular tachycardia (SVT).

It is vital to highlight that the specific cardiac problem determines the drug used, the underlying reason for the higher heart rate, and the patient’s distinctive characteristics.

10. Conclusion

Amlodipine is a class of calcium channel blocker drugs used to treat cardiovascular diseases caused by high heart rates. As discussed earlier in the article, amlodipine lowers the heart rate. Still, unlike other calcium channel blockers, it has little effect on the heart as it primarily reduces blood pressure. Along with other drugs, amlodipine also has a synergistic effect, increasing its efficacy in lowering the heart rate.

Last Updated on March 24, 2024 by Gautam