3. Drugs stimulating fibrinolysis. Classification. Mechanism of action. Indications for use. Side effects. Contraindications. Comparative assessment.

Fibrinolytic agents are agents that can dissolve existing blood clots.

Fibrinolysin, streptokinase, thrombolysin, urokinase, nicotinic acid, eminase, alteplase.

The mechanism of action is that they activate the physiological system of fibrinolysis.

One of the widespread fibrinolite drugs is streptokinase. It is produced by b-hemolytic streptococci of group C. It interacts with profibrinolysis, this stimulates the transition of profibrinolysis to fibrinolysin. Fibrinolysin dissolves fibrin. Streptokinase is effective for fresh blood clots.

Indications: dissolution of blood clots in coronary vessels during myocardial infarction, pulmonary embolism, deep vein thrombosis, acute blood clots of different localization.

Contraindications: bleeding, hypotension, fever, allergic reactions.

Urokinase is less likely to cause allergic reactions than streptokinase

4. Halogen-containing antiseptics. Classification. Mechanism of action. Indications for use. Side effects. Contraindications. Comparative evaluation of preparations.

Antiseptics are medicinal substances that suppress microorganisms on the surface of the body, on the skin and mucous membranes.

Halogenated: chlorhexidine, chloramine B, alcohol iodine solution, bleach, pantocid.

Mechanism of action: chlorine-containing substances form active chlorine and hypochlorous acid, which decays to form atomic oxygen. It enters into a connection with proteins of a microbial cell, oxidizes and coagulates. The released active chlorine replaces hydrogen atoms at the nitrogen atom of proteins, causing denaturation with the subsequent death of the microbial cell.

Indications: disinfection of household items, tools, surgeon's hands, infected wounds. Chlorhexidine is used to treat cavities.

Side effects: dry skin, dermatitis.

Ticket 3.

1. Suction of medicinal substances from the place of administration. Transportation of medicinal substances through cellular membranes.

Oral route.The medicine taken by mouth first meets the acidic environment of the stomach and may lose its effectiveness. In addition, some foods slow down the process of digestion and evacuation from the stomach. Therefore, drugs must be taken either 30 minutes before meals, or 1 hour after. Solutions and powders are absorbed faster than tablets and capsules. Medicines designed for intestinal absorption (protected by a membrane from the effects of acid and pepsin) are resorbed in a weakly alkaline medium (pH 8.0 - 8.5). Fat-soluble drugs are also absorbed from oil solutions (for example, vitamins D, E, A, etc.), but only after the oil is emulsified with bile acids. After absorption in the stomach and intestines, medicinal substances enter the liver through the portal vein system, where they are partially bound and rendered harmless. Only after passing through the liver,

Sublingual way.Due to the rich vascularization of the oral cavity, the absorption of the preparations occurs quickly. They are not affected by proteolytic enzymes and hydrochloric acid. Such prepats are in the process of emergency assistance (antianginal). They enter the superior portal vein system and further into the general bloodstream, bypassing the liver.

Rectal pathway... The rectal route is used when it is impossible to use drugs inside (vomiting, unconsciousness). From the rectum, 50% of the dose is absorbed into the inferior vena cava system, bypassing the liver, 50% enters the portal vein and is partially inactivated in the liver.

Subcutaneous route. The drugs should not have an irritating effect (subcutaneous fatty tissue is rich in nerve endings) and cause vasospasm. The pharmacological effect occurs 15 to 20 minutes after injection. When solutions of the irritating substance calcium chloride and the strong vasoconstrictor noradrenaline are injected under the skin, necrosis occurs. This route of administration is commonly used in emergency response at the scene of a disaster for injections of pain relievers, vasoconstrictors, psychosedatives, tetanus toxoid, etc. This is the usual route of administration of insulin.

Intramuscular route. The introduction by this method is less painful than the introduction into the subcutaneous tissue. The most rapidly resorption comes from the deltoid muscle of the shoulder, more often in practice it is done in the outer upper quadrant of the gluteus muscle (it is more voluminous, which is important with multiple injections). When injecting oil solutions or suspensions, you must first make sure that the needle does not get into the vessel. Otherwise, vascular embolism with serious consequences is possible. Absorption can be accelerated by applying a heating pad or, alternatively, slowed down with an ice pack.

Intravenous route. Here, in a short time, the maximum (peak) concentrations of the substance in the heart are reached, high in the central nervous system, only then its distribution in the body occurs. Some drugs may experience sensitization (that is, they have become allergens for the patient) or genetically determined hypersensitivity (idiosyncrasy). refusal of some drugs is required (novoca-ina, penicillins, etc.). Idiosyncrasy causes lightning-fast development of toxic reactions, which are impossible to predict. Therefore, injections of substances that are especially dangerous in this regard (iodine-reducing X-ray contrast drugs, quinine, etc.) are made in two stages: first,

a test dose (no more than 1/10 of the total) and, after making sure that the drug is sufficiently tolerated, the rest is injected after 3 - 5 minutes. Some substances irritate the vein wall. They should first be strongly diluted in an infusion solution (saline, glucose) and administered drip.

Intra-arterial pathway... The introduction of drugs into an artery is resorted to for special purposes, when it is necessary to create a large concentration of a drug (for example, an antibiotic, an antitumor agent, etc.) in the tissue or organ supplied by it.

It should be borne in mind that the walls of the arteries, in contrast to the venous ones, contain a significant amount of bound catecholamines (norepinephrine, adrenaline), which, when a substance with irritating properties is injected, can be released and cause a persistent spasm of the vessel with necrosis of the supplied tissue.

Intraosseous pathway.In terms of the rate of distribution of matter in the body, this path approaches the intravenous route. Applied only for extensive burns or situations that do not allow to enter otherwise.

Intracardiac path... This method of administering drugs (usually adrenaline) is practiced only in one case - during emergency therapy for cardiac arrest. The injection is made into the cavity of the left ventricle and accompanied by cardiac massage.

Subarachnoid path... It is used to inject local anesthetics or morphine-like analgesics (spinal anesthesia) into the spinal canal with a puncture of the membranes of the brain, as well as for chemotherapy of meningitis - infections that nest in the meninges and are difficult to access for drugs (penicillins, aminoglycosides, etc. etc.) introduced in other ways. Injections are usually done at the level of the lower thoracic - upper lumbar vertebrae. and. For punctures, it is advisable to use thin needles, since the hole in the dura mater is poorly tightened and the cerebrospinal fluid oozes through it into the tissue. This causes changes in intracranial pressure and severe headaches.

Biological barriers: mucous membrane of the stomach, intestines, oral cavity, nasopharynx, skin, geb, placental, mammary epithelium, renal.

Diffuse transport. The bottom line is that lipid-soluble substances easily dissolve in the membrane and move inside the cell by diffusion until the concentration outside and inside becomes the same. Moreover, they can accumulate in the membrane. (alcohols, ethers, etc.)

Pinocytosis. The substance comes into contact with the membrane and this area bends inward, the edges close, a bubble is formed. It is transferred inside the cell. Some proteins are polypeptide hormones.