3. Class III antiarrhythmic drugs (potassium channel blockers). Mechanism of action. Indications for use. Side effects. Contraindications Comparative evaluation of drugs.

Class III - substances that cause a uniform lengthening of the repolarization phases and the action potential.

AMIODARON5 (cordaron)

SOTALOL5 (sotakor, sotalex)

BRETILIA TOSILATE (Ornid)

NIBENTAN

IBUTILID

DOPETHYLIDE

DRONEDARON

Mechanism of action:They block β-adrenergic receptors of the myocardium, and the degree of blockade depends on the state of the tone of the ANS, it can be increased with the predominance of the tone of the sympathetic part of the nervous system. As you know, catecholamines have an arrhythmogenic effect by stimulating the β1-adrenergic receptors of the myocardium, β-blockers protect it from the arrhythmogenic effect of excess catecholamines with hyperfunction of the sympathetic division of the ANS.

Also β-blockers exhibit a direct membrane-stabilizing effect, blocking Na channels in concentrations exceeding the therapeutic one.

Indications:

- treatment of atrial fibrillation and atrial flutter;

- relief and prevention of supraventricular tachycardia;

- treatment of arrhythmias in patients with mitral valve prolapse and hypertrophic cardiomyopathy;

- treatment of ventricular and supraventricular arrhythmias in patients with coronary artery disease;

- treatment of catechol-dependent ventricular tachycardia.

Side effects: - bronchospasm; - violation of peripheral circulation; - fatigue;

- in patients with diabetes - hyperglycemia; - gastrointestinal disorders; - rash, fever, "withdrawal syndrome".

Contraindications: - severe broncho-obstructive syndrome (bronchial asthma, asthmatic bronchitis); - violations of peripheral circulation (Raynaud's disease, obliterating endarteritis); - diabetes.

Amiodarone - the action develops slowly, also blocks sodium channels in the heart, noncompetitively blocks beta-adrenergic receptors and calcium channels, reduces myocardial oxygen demand, lowers heart rate, lowers blood pressure, improves coronary circulation.

Ornid - moderately lowers blood pressure.

4. Dyes. Detergents. Oxidizing agents. Acids and alkalis.

Classification: Organic:

- (brilliant green, ethacridine lactate, methylene blue),

-detergents (chlorhexidine, cerigel, roccal).

Inorganic: - oxidizing agents (hydrogen peroxide, potassium permanganate),

acids and alkalis (boric, salicylic, benzoic acids, ammonia solution, sodium bicarbonate, sodium tetraborate, calcium hydroxide).

Dyes - antiseptic effect, antidote for cyanide poisoning; externally for the treatment of wounds.

Detergents - cationic soaps, washing and antiseptic properties, for hand treatment, sterilization of instruments.

Chlorhexidine - antiseptic, bactericidal and fungicidal action. For the treatment of wounds, hands, sterilization. For dermatitis and allergies, do not use.

Oxidants: hydrogen peroxide - releases O2 and forms foam, mechanical cleaning of the wound occurs; antiseptic and deodorizing effect.

Potassium permanganate - in the presence of organic substances, it removes O2, manganese oxide is formed; antimicrobial, deodorizing, astringent action. For the treatment of wounds, gastric lavage.

Acids are antiseptic, fungicidal, irritating, distracting. Outwardly.

Sodium bicarbonate - antacid, anti-inflammatory; for rinsing, rinsing.

Na tetraborate - antiseptic, topical.

Ammonia solution (ammonia) - for hand treatment, inhalation to stimulate breathing.