3. Class II antiarrhythmic drugs (Beta-blockers). Classification. Mechanism of action. Indications for use. Side effects. Contraindications Comparative evaluation of drugs.

Class II - substances that limit the neuro-sympathetic effects on the heart.

Classification:

1) Non-cardioselective: -Anaprilin (beta1,2), pindolol, timolol, nadolol.

2) Cardioselective: -Metoprolol (beta1), talinolol (beta 1), nebivolol, atenolol, bisoprolol.

Each of the presented groups is subdivided into two subgroups:

Drugs without sympathomimetic activity (without SMA)

Drugs with sympathomimetic activity (with SMA)

Mechanism of action: blockade of beta-adrenergic receptors of the myocardium, blood vessels, bronchi. They reduce automatism, slow down conduction, increase the effective refractory period (in the AV node), reduce the force of myocardial contraction, reduce the sympathetic effect, and reduce the need for oxygen.

Indications: ischemic heart disease, arterial hypertension, tachyarrhythmia (atrial and ventricular).

Side effects: increase the tone of the bronchi (not possible with bronchial asthma), bradycardia, allergies, conduction disturbances, impaired peripheral circulation, hyperglycemia, withdrawal syndrome, weakness, lethargy.

Contraindications: bradycardia, heart failure, bronchial asthma, diabetes mellitus, pregnancy, hypotension, impaired peripheral circulation.

Anaprilin - reduces heart rate and the strength of heart contractions, can provoke bronchospasm, reduces the activity of the sinus node and excitability, slows down the rhythm, reduces contractility, heart function decreases.

Talinolol - reduces contractility less, lowers blood pressure.

The most cardioselective drugs: nebivolol, bisoprolol.

Celiprolol blocks beta 1 receptors, but at the same time has some stimulating effect on beta 2 receptors, so it has no side effects from the bronchi, carbohydrate and lipid metabolism.

Nebivolol has a vasodilating effect by increasing the synthesis and release of nitric oxide, and has antioxidant properties.

Esmolol is the shortest-acting drug used only as an intravenous infusion.

4. Complications arising from the use of antibiotics, measures for their prevention.

1. Neurotoxic - damage to 8 pairs of cranial nerves, neuromuscular block.

2. Nephrotoxic; 3. Inhibition of hematopoiesis; 4. Irritation of the gastrointestinal tract; 5. Teratogenic action; 6. Dysbacteriosis, candidomycosis; 7. Allergic reactions - skin, anaphylactic shock, serum sickness, agranulocytosis; 8. Reduction of the therapeutic effect - with the indiscriminate use of antibiotics, non-compliance with dosages, frequency of use, course doses.

The success of antibiotic therapy depends on the fulfillment of the following basic conditions:

- it is necessary not only to choose the right antibiotic, but also to cancel it in a timely manner;

- when finishing antibiotic therapy, the drug is canceled immediately, and not gradually;

- the duration of the course of antibiotic treatment should be at least 6 - 8 (sometimes 10) days;

- with combined treatment with antibiotics with glucocorticoids, the antibiotic is canceled 3 to 5 days after the end of the course of hormone therapy;

- uncontrolled prescription of antibiotics leads to allergization of patients and an increase in the number of antibiotic-resistant microorganisms;

- the method of administration of antibiotics is selected depending on the localization of the infection, must be individual and quickly create the optimal concentration of the drug in the focus of infection;

- the frequency of antibiotic administration is determined by the duration of the bacteriostatic or bactericidal concentration of the drug in the blood;

- the maximum effectiveness of antibiotics is achieved when combined with other antimicrobial, antihistamines and vitamin preparations.