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Antianginal Drugs And Heart Attacks: Everything You Need To Know

What is angina and what are the types of angina?

If you experience discomfort every time you cross a threshold of activity, emotional stress, or exercise, it is known as stable angina. In some cases, angina appears all of a sudden at rest or in the early mornings and this is known as unstable angina.


Stable angina is usually caused due by the reduction of the size of the lumen of the blood vessels, Unstable angina is caused due to a narrow area of the vessel getting temporarily blocked due to contraction of an artery or a clot.


Unstable angina is more unpredictable and dangerous and requires immediate medical attention.


However, both types of angina point to a weakness in the circulation of the heart and the pain is a symptom of some of the heart muscles not getting enough oxygen.


What is anti-anginal medication?

When you visit the doctor with angina, they will recommend a series of tests to determine the exact state of your cardiovascular health like exercise tolerance tests on a treadmill or other tests to see the electrical activity of the heart through ECGs of the blood flow in the heart through advanced imaging studies.


Your doctor may also recommend angioplasty for unstable angina to look for and clear any blockages that may be there. This procedure may also be combined with inserting stents that keep the vessel dilated and allow blood to flow. This is a treatment for the condition, but the chances of developing the condition again remain high because usually, it's not just one area that develops a problem at a time.


Either after treatment or to prevent the occurrence of complications, your doctor may recommend a series of medications that help to reduce the risk of cardiovascular events. This is known as anti-anginal medication. Anti-anginal medications work by improving blood circulation in the heart, reducing the contraction of blood vessels and blood pressure against which the heart has to pump blood, or preventing or reducing the formation of clots in the bloodstream.


What are the types of anti-anginal medications?

Most of the anti-anginal medications given to you will fall under one of the following categories. You may find this out by reverse searching the name of the compound in the medicine on an online search platform.


Medicines usually prescribed for stable angina:

  1. Nitrates:

Nitrates expand the arteries and veins and help more blood to flow through them by improving the lumen size. Nitrates may be recommended during morning or night hours based on the type of angina you experience.

    1. Sublingual nitroglycerin - is usually prescribed as an SOS solution for sudden angina or as a preventive measure while engaging in activities that can cause angina. Your doctor will advise you on how to use it by keeping it in a moist area below the tongue. They are a quick fix and work within two to five minutes and the effects last fifteen to twenty minutes.
    2. Oral nitrates
      1. Isosorbide dinitrate — ISDN - usually given 2-3 times a day, acts within 15-30 minutes, and effects last 3-6 hours. Usually, your doctor will tweak a schedule for you to prevent developing tolerance.
      2. Isosorbide-5-mononitrate - ISMN - usually begins acting within 30 minutes and the effect last 6-8 hours. An extended-release medication is needed only once a day. It is important to stick to the exact dosage and schedule as recommended by your doctor.
    3. Transdermal nitroglycerin - Method of continuously delivering nitroglycerin from a small patch. The patches also face the problem of developing tolerance in the body and should also be used only exactly as recommended to you by your doctor.


    1. Adrenergic Blockers (specifically beta-blockers):

    Beta-blockers are used to block the signals of the sympathetic nervous system and the adrenergic elements from raising the heart rate, blood pressure, and the force of contraction. These medicines help by reducing the load against which the heart has to pump blood and also by reducing the total oxygen the heart requires to sustain functionality. This reduces the damage from any blockage and is known to improve survival and prevent heart attacks. Some of the types of beta blockers used include:

      1. Non-selective - they target not just the heart and circulatory system, but also other areas where the beta receptors are functional. (example - propranolol)
      2. Cardio-selective - these medicines like atenolol and metoprolol block only the beta-adrenergic receptors in the heart at lower doses. These may be more effective for people who have other problems like obstructive lung disease etc.

    It is important to remember never to suddenly stop taking beta blockers as withdrawal can be dangerous by exacerbating angina, heart attack, and death. Especially when a high dosage is stopped abruptly. Always speak to your doctor before deciding to change medication yourself.


    1. Calcium channel blockers:

    These medicines work by reducing the tone of muscles in the blood vessel walls, leading to more dilated arteries and lower blood pressure. This reduces the overall load on the heart and thus the requirement for oxygen or the shock from suddenly reduced circulation. They provide both a way to prevent heart attacks and to reduce the morbidity from an impending attack. They are usually recommended for stable angina only when the nitrates and beta blockers fail to achieve necessary results or cause side effects. These include:

      1. Dihydropyridines - like amlodipine, and nifedipine work mainly by dilating blood vessels. They cause sudden dilation of blood vessels and you may experience symptoms like flushing, edema, or lightheadedness
      2. Verapamil - works by reducing the heart’s electrical system and slowing down the heart rate and the force of contractions. Although not as effective as beta-blockers, it is better in some individual contexts, which your doctor may evaluate.
      3. Diltiazem - They are far less aggressive than the above two options in both reducing heart rate and dilating blood vessels.
    1. Ranolazine - A new drug that is used to treat angina with a complex mechanism of action. This medication may be added as an addition to nitrates, beta-blockers, or calcium channel blockers
    2. Aspirin - Aspirin reduces the chances of clots forming in the narrowed coronary artery. This protects the heart from a potential complete blockage from a clot in someone who is already having stable angina.


    Medications for other conditions:

    Other conditions may need to be treated along with angina. These may include separate medications for the treatment of:

    1. High blood pressure
    2. High Cholesterol or Lipid abnormalities
    3. Smoking
    4. Excess weight
    5. Anxiety and stress


    Dr. Mahim Saran
    Cardiac Care
    Meet The Doctor
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