Beta-blockers – action, types, indications, side effects

Proven content

The task of beta-blockers is to influence the sympathetic nervous system. It belongs to the autonomic nervous system responsible for the work of many systems. Thanks to it, the human body copes better with stressful situations, hence it is often referred to as a “fight and flight” system. Check how beta-blockers work.

Beta-blockers are antagonists of the β1 and β2 receptors. They inhibit the sympathetic nervous system and thus have a huge impact on almost the entire human body. They are used, inter alia, in in cardiology, however, they may be encountered in the treatment of many other diseases.

Beta-blockers – action

Beta-blockers are quite broad-based. Depending on the place in the human body, they have a different effect:

1. heart – beta-blockers cause a decrease in heart rate, a decrease in contractility of the heart muscles, a decrease in atrioventricular conduction, as well as a decrease in the stroke volume of the heart, an increase in blood flow through the coronary vessels and lower oxygen consumption by the heart;
2. blood vessels – beta-blockers reduce peripheral resistance and relax blood vessels;
3. smooth muscle contraction;
4. lowering blood pressure due to a decrease in renin secretion;
5. reduced production of aqueous humor in the eye and thus lower intraocular pressure.

Beta-blockers – types

There are many different types of beta blockers. Their basic division relates to the selectivity of the beta-adrenergic receptor blockade:

1. non-selective drugs (blocking both β1 and β2);
2. selective drugs (blocking the β1 receptor) – they are safer and free from numerous side effects.

Drugs from the group of beta-blockers can also be divided into those that additionally exhibit intrinsic sympathomimetic activity and those that have the ability to stabilize cell membranes.

In addition, the breakdown of beta-blockers can be made on the basis of drug generation:

1. generation I – classic non-selective drugs such as the most popular propranolol;
2. generation II – selective drugs that block only the β1 receptor;
3. XNUMXrd generation – beta-blockers with an additional vasodilating effect due to two different mechanisms: direct (stimulating the release of nitric oxide) and indirect (blockade of the α-adrenergic receptor).

Beta-blockers – indications

There are many indications for the use of beta-blockers. They are most often used selectively on β1 receptors, and therefore as part of cardiological treatment. However, non-selective drugs are prescribed much less frequently. Beta-blockers from this group are used, for example, in the treatment of anxiety disorders and essential tremor, and in the prophylaxis of migraines.

Regarding the safety of beta-blockers, non-selective drugs should not be prescribed to pregnant women. Non-selective beta blockers can reduce blood flow in both the uterus and the placenta. Therefore, the doctor always selects the type of beta-blockers based on the interview with the patient, other diseases and medications taken.

The indication for the use of beta-blockers in cardiology is:

1. ischemic heart disease;
2. heart failure;
3. hypertension;
4. Heart arythmia.

Beta-blockers are also used to treat open angle glaucoma. Treatment is aimed at lowering the intraocular pressure by reducing the production of aqueous humor in the eye. Beta-blockers are an effective and safe way to fight glaucoma, because they do not affect, for example, the width of the pupils and the accommodation of the eye. In addition, they are long-lasting and can only be used twice a day.

Beta-blockers – side effects

While beta-blockers are considered effective, they can also cause many side effects. The most frequent appearances include gastrointestinal complaints, brachycardia, depression, hallucinations, memory disorders, cold hands and feet, exacerbation of asthma symptoms, impotence, or disturbances in carbohydrate metabolism.

Beta-blockers – contraindications

Beta-blockers are contraindicated in people with asthma and second and third degree AV block. Other contraindications include chronic obstructive pulmonary disease, peripheral arterial disease, severe hypotension, bradycardia, vasospastic angina, metabolic syndrome and glucose intolerance. Beta-blockers are also not recommended for people who are very active and professionally involved in sports.

Before use, read the leaflet, which contains indications, contraindications, data on side effects and dosage as well as information on the use of the medicinal product, or consult your doctor or pharmacist, as each drug used improperly is a threat to your life or health.