3. Class IV antiarrhythmics (calcium channel blockers). Classification. Mechanism of action. Indications for use. Side effects. Contraindications Comparative evaluation of drugs.

Substances that block slow calcium channels of the cell membrane, i.e. inhibit the depolarization of cells with a slow electrical response: VERAPAMIL, DILTHIAZEM, BEPRIDIL, GALLOPAMIL, TIAPAMIL

Mechanism of action

Class IV drugs selectively block slow Ca channels and Ca2 + current into myocardiocytes. Under physiological conditions, a slow Ca2 + current is involved only in the depolarization of the sinus and atrioventricular nodes, but with arrhythmias it also appears in the altered myocardium of the atria and ventricles.

Among Ca antagonists, drugs of the verapamil and diltiazem groups have an antiarrhythmic effect. These drugs reduce the transmembrane resting potential and lengthen the refractory period, as a result conduction slows down and the automatism of the sinus node decreases, the mechanism of recurrent excitation is suppressed in supraventricular tachyarrhythmias.

Indications for use: - prevention and relief of supraventricular tachyarrhythmias.

Side effects: - arterial hypotension; - decrease in atrio-ventricular and ventricular conduction, bradycardia, blockade; - proarrhythmic effect (ventricular tachycardia of the "pirouette" type - can turn into atrial fibrillation and cause sudden death); - decrease in myocardial contractility, worsening of the course of CHF, decompensation of heart failure; - allergic reactions (rash, itching, urticaria).

- verapamil: dizziness, headache, nausea, edema, constipation, gingival hyperplasia;

- diltiazem: dizziness, headache, dermatitis, increased liver enzymes, weakness.

Contraindications: - arrhythmias caused by glycosidic intoxication. - arterial hypotension; - bradycardia, AV blockade (especially 2-3 degrees), SSSU; - CH, CHS; - Acute left ventricular failure (pulmonary edema, cardiogenic shock); - individual intolerance to the drug.

4. Antimicrobial agents-derivatives of quinolone. Classification. Mechanism of action. The nature of the action. Spectrum of action. Indications for use. Side effects. Contraindications Comparative evaluation of drugs.

Antimicrobials are medicines used to treat infections caused by bacteria, fungi, viruses.

Classification:

1.Qinolones of the 1st generation (nalidixic acid, oxolinic acid, pipemidic acid)

2.2 Generation (ciprofloxacin, norfloxacin, ofloxacin, pefloxacin, lomefloxacin)

3.3 generation (sparfloxacin, levofloxacin)

4.4 generation (moxifloxacin, gemifloxacin)

The mechanism of action of all quinolones

- blockade of the enzyme DNA gyrase (gyrus - thread) of the microbial cell. This enzyme cross-links two DNA strands and thus participates in the processes of DNA transcription and replication. When DNA gyrase is inhibited, DNA despiralization occurs. This mechanism provides high selectivity and specificity of the quinolones action.

The nature of the action is bactericidal

All quinolones are incompatible with nitrofurans (efficiency drops sharply)

Spectrum of action I generation

non-fluorinated quinolones

narrow - Gr (-) sticks (E. coli, shigella, salmonella, protea, klebsiella)

Do not create a therapeutic concentration in blood and tissues. They are used for urinary tract infections, as they are completely excreted by the kidneys, creating therapeutic concentrations in the urine

Nalidixic acid (nevigramone, blacks)

Used 4 times a day (T1 / 2 1 - 2 hours). The effectiveness is increased by alkalinization of the urine. Microbial resistance develops rapidly

1st generation

non-fluorinated quinolones

• Indications: Acute cystitis, anti-relapse therapy of chronic pyelonephritis (in acute pyelonephritis, it is ineffective, since the drugs accumulate little in the kidney tissues)

Side effects: Gastrointestinal tract - heartburn, epigastric pain, nausea, vomiting, diarrhea (taken after meals)

CNS - an exciting effect, can manifest itself with tremors, insomnia, paresthesias, a decrease in the seizure threshold

Blood - leukopenia, thrombocytopenia, in patients with genetic deficiency of glucose-6-phosphate dehydrogenase - hemolytic anemia

Liver - cholestatic jaundice, hepatitis

• Contraindications: Fluoroquinolone: ​​History of convulsive syndromes

• Deficiency of the enzyme glucose-6-phosphate dehydrogenase

• Pregnancy (possibly inhibition of the development of cartilage tissue in the fetus)

• Lactation

• Children's age (up to 10 - 12 years old due to the possibility of inhibition of the development of cartilage tissue)

Comparative characteristics:

Nifuroxazide (enterofuril) is used for intestinal infections (acute infectious diarrhea, enterocolitis). Practically not absorbed in the digestive tract. Does not disturb the normal intestinal microflora

Furazolidone is currently used only for giardiasis as a reserve drug. NB! In combination with alcohol, it can cause a teturam-like reaction. Inhibits MAO, therefore, in combination with other MAO inhibitors, sympathomimetics, tricyclic antidepressants and tyramine-containing foods, there is a risk of developing a hypertensive crisis

Nifuratel (makmiror) is used for intestinal infections (acute infectious diarrhea, enterocolitis), giardiasis, intestinal amebiasis, trichomonas vulvovaginitis

Furacilin is used as an antiseptic for treating wounds, skin, mucous membranes, for washing serous and articular cavities.