The rate of development of the effect, its severity and duration depends on the routes of administration and dose. Sometimes the route of administration determines the nature of the action. Routes of administration: enteral and parenteral.
Enteral: through the mouth, under the tongue, buccal, into the duodenum, rectally. When administered by mouth, sterility is not required. Absorption often occurs in the small intestine (large absorption surface and intensive blood supply), the process is relatively slow, first the substances enter the liver, then into the blood. If the drug degrades absorption quickly, the hepatic barrier bypasses, even at a small dose. Into the 12-finger, the intestine is introduced through a tube. Rectally - enters the bloodstream, bypassing the liver; not affected by gastrointestinal enzymes.
Parenteral: subcutaneous, intramuscular, intravenous, intravenous, intrasternal, intraperitoneal, inhalation, subarachnoid, intrapleural, transdermal, intranasal. Most often under the skin, into a muscle, into a vein (the effect is the fastest). In oil, injected i / m to prolong the effect. Irritating substances in / m and s / c are not administered (necrosis). IV is injected slowly, insoluble compounds, oil solutions (embolism), irritating substances (thrombophlebitis), drugs that cause blood coagulation or hemolysis cannot be injected. In / arter introduction is used in the diagnosis of tumors, blood clots. Intrasternal route is taken if IV is impossible (children, old people). In / peritoneally enter during operations. Inhalation aerosols. Into the islands, poorly penetrating through the BBB, are introduced under the membranes of the brain. Dose - number of in-va for 1 reception. Distinguish between single, daily, doses, course dose (antibiotics), loading dose.
Classification:
Stimulating alpha and beta-adrenergic receptors: ADRENALINE HYDROCHLORIDE (beta 1,2, alpha 1,2) NORADRENALINE HYDROTARTRAT (alpha 1,2, beta1)
Stimulating predominantly alpha-adrenergic receptors: MESATON (alpha1), NAFTHISIN, GALAZOLINE (alpha2)
Stimulating predominantly beta-adrenergic receptors: ISADRIN (1,2). SALBUTAMOL, PHENOTHEROL (2). DOBUTAMINE (1)
ADRENALIN - belongs to the group of phenylalkylamines, is a biogenic catecholamine.
Main pharmacological effects:
CNS - increases excitability, improves cerebral circulation, stimulates the secretion of adrenorcorticotropic hormone (ACTH) by the adenohypophysis
EYE- dilates the pupil due to contraction of the radial muscle of the iris, practically does not affect accommodation (since there are no adrenergic receptors in the ciliary muscle). It complicates the outflow of intraocular fluid, but reduces its production (inflow) due to the narrowing of the retinal vessels. The latter effect is predominant; therefore, intraocular pressure as a whole is somewhat reduced. This makes it possible to use the drug in the open-angle form of glaucoma (associated with excessive production of intraocular fluid), but in the closed-angle form (associated with a deterioration in outflow), adrenaline is contraindicated
SPLEEN - reduces the capsule and trabeculae, which leads to the release of deposited erythrocytes and platelets into the blood.
BRONCHI - expands
A HEART - increases the strength of heart contractions, conduction, excitability, automatism, increases stroke and minute blood volumes. It mainly causes tachycardia, which, however, can be replaced by bradycardia. The latter is associated with the emergence of vagal reflexes from vascular baroreceptors (aortic arch, carotid sinus zone) in response to an increase in the stroke volume of blood.
Activates metabolic processes in the myocardium. Improves blood supply to the myocardium (due to the expansion of the coronary vessels)
Epinephrine is effective when administered locally and parenterally (subcutaneous, intravenous, intramuscular). Duration of action - from 5 to 30 minutes
Indications Locally - as a vasoconstrictor for rhinitis, conjunctivitis - open-angle glaucoma - to enhance and prolong the action of local anesthetics Resorptively: - anaphylactic shock, status asthmaticus, serum sickness, angioedema - hypoglycemic coma - cardiac arrest
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Side effects: insomnia, tremors, hypertension, tachycardia, arrhythmias, pain in the heart, nausea, vomiting
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Contraindications:hypertension, atherosclerosis, ischemic heart disease, hyperthyroidism, diabetes mellitus, pregnancy, angle-closure glaucoma, fluorothane and cyclopropane anesthesia (these anesthetics increase the sensitivity of the myocardium to catecholamines, as a result of which arrhythmias can develop, up to ventricular fibrillation and death). Adrenaline is contraindicated in all types of shock, with the exception of anaphylactic
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MEZATONE - Causes a vasoconstrictor effect and raises blood pressure weaker than adrenaline and norepinephrine, but for a longer period (intravenously - up to 20 minutes, subcutaneously - 40-50 minutes). This is due to the fact that mezaton is a synthetic preparation, it is not a catecholamine, therefore it is not destroyed by the COMT enzyme. Effective when taken orally. It can be used in conditions of cyclopropane and fluorothane anesthesia. From the heart causes bradycardia (reflex)
Indications Locally - as a vasoconstrictor for rhinitis, conjunctivitis - open-angle glaucoma - to enhance and prolong the action of local anesthetics resorptively (intravenous, intramuscular, subcutaneous) - collapse and hypotension of vascular origin, preparation for surgery, intoxication, infectious diseases with a decrease in blood pressure |
Side effects insomnia, tremors, hypertension, tachycardia, arrhythmias, pain in the heart, nausea, vomiting
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Contraindications - cardiogenic shock - hypovolemic - hypertension, - atherosclerosis, - coronary artery disease, - hyperthyroidism, - diabetes, - pregnancy, - angle-closure glaucoma |
Poisoning: 1) cardiac symptom - a sharp bradycardia (vagus), then tachycardia (the vagus is excited, but sharply ↑ myocardial automatism), extrasystole (loss of K +), bifurcation of the rhythm, partial or complete block (the ventricles have their own rhythm - fibrillation and flickering); 2) gastrointestinal tract - loss of appetite, nausea, vomiting; 3) CNS - anxiety, hallucinations, ↓ vision; 4) diuresis ↓ sharply; 5) shortness of breath ↑.
Assistance measures: 1. Cancellation of the drug or dose reduction; 2. Introduction of potassium preparations; 3. Binding of calcium ions (sodium citrate, EDTA-disodium salt); 4. Introduction of donors of sulfhydryl groups (unitiol, cysteine, taurine); 5. Decrease in myocardial excitability (anaprilin); 6. Control of arrhythmias by specific means (diphenin, lidocaine); 7. Preparations of vitamins B and E; 8. Metabolic agents - succinic acid and its derivatives (sufan), riboxin (inosine); 9. Camphor; 10. Cholesteramine, activated carbon; 11.Atropine sulfate (for blockages); 12. Blood transfusion; 13. Oxygen therapy.
4. Antibiotics of the penicillin group. Classification. Mechanism of action. Action character. Spetr of action. Indications for use. Side effects. Contraindications Indications. Comparative evaluation of drugs.
Classification: Natural (biosynthetic)
Parenteral: short-acting (3-4 hours) benzylpenicillin sodium salt
long-acting (depot-penicillin): benzylpenicillin novocaine salt, bicillin 1.5
Oral: phenoxymethylpenicillin
Semi-synthetic: a) resistant to penicillase: oxacillin, nafcillin, cloxocillin.
b) Broad spectrum of action: ampicillin, amoxicillin
c) A broad spectrum of action with antipseudomonal activity: carbenicillin
d) Inhibitor-protected: amoxiclav, trifamox, tazocin, tymentin.
e) Combined: ampiox.
Mechanism: inhibit the synthesis of cell wall components, prevent the formation of peptide bonds.
Mode of action: bactericidal, affect only dividing cells.
Spectrum e: gram (+) predominantly staphylococci, streptococci, meningococci, gonococci, spirochetes, clostridia, causative agents of diphtheria, anthrax, listeria.
Indications: upper respiratory tract infections (scarlet fever), erysipelas, rheumatism, pneumonia, meningitis, endocarditis, syphilis, leptosporosis, anaerobic infections.
Side effects: allergies, dysbiosis, glossitis, stomatitis, dyspepsia.
Contraindications: individual intolerance, allergies.
Benzylpenicillins act briefly (3-4 hours), bicillin - long-term (once every 7-14 days, months). Oxacillin is resistant to penicillinase, it is destroyed in an acidic environment. Nafcillin penetrates the BBB. Ampicillin is destroyed by penicillinase, acid-resistant. Carbenicillin is destroyed in an acidic environment and by penicillinase.
Benzylpenicillin is widely used in pediatrics because low toxicity, it can be administered in large doses. Not effective when taken by mouth, even in young children with low gastric acidity. Penicillin is a GABA antagonist and can cause seizures when given in large doses. The younger the child, the greater the risk of developing seizures. Ampicillin, when administered orally, causes diarrhea in a third of children. Oxacillin is capable of impairing liver function.
1. Conditions affecting the manifestation of the action of medicinal substances in the body. The importance of the psychogenic factor in the effectiveness of drug treatment; the word of the doctor and the prescription of drugs. The ethical side of the advertising of new drugs.
Age - there is perinatal pharmacology (from 24 weeks of the fetus to 4 weeks of newborn), newborns differ from adults (deficiency of enzymes, kidney function, ↑ BBB permeability, underdevelopment of the central nervous system). There is pediatric pharmacology - doses per kg of body weight. There is geriatric pharmacology - in people of age, the doses should be ↓ (since ↓ absorption, metabolism, excretion by the kidneys).
Gender - men are less sensitive to a number of substances than women (strychnine, nicotine).
Genetic factors - enzyme deficiency, atypical reactions (idiosyncrasy). Studying pharmacogenetics.
The state of the body - pharmacokinetics changes with illness, pregnancy, obesity.
Circadian rhythms (circadian) - studies chronopharmacology. The effect of substances changes qualitatively and quantitatively (pronounced effect during the period of maximum activity). Absorption, metabolism change during the day.
Psychogenic factor - if the patient is committed to treatment, trusts the doctor, follows the recommendations, the treatment will be effective. Otherwise, the effect of the treatment cannot be expected.
The word of the doctor is the therapeutic effect of the word of the doctor on the patient.
Ethics:
2. Sedatives. Classification. Mechanism of action. Indications for use. Side effects. Contraindications Comparative evaluation of drugs.
Sedatives - Drugs that have a regulating effect on the functions of the central nervous system, enhancing inhibition processes and lowering arousal processes.
Classification:
1) Bromides: sodium bromide, potassium bromide.
Mechanism of action: increases the processes of inhibition to the process of excitation.
Indications: neurasthenia, neurosis, hysteria, increased irritability, insomnia, the initial form of hypertension.
Side effects: with prolonged use, the phenomena of bromism develop (skin rash, rhinitis, bronchitis, weakening of memory, hearing, vision), cough, runny nose, weakness.
2) Herbal preparations: valerian tincture, valerian infusion, thick valerian extract, motherwort tincture and extract, novo-passit.
Mechanism of action: suppresses the processes of excitation before inhibition.
Indications: CVS neuroses, insomnia, increased nervous excitement.
Side effects: allergies.
3) Combined drugs: corvalol, valocordin.
Indications for use: nervousness, irritability, neurasthenia, insomnia, of a particular neurological nature.
Contraindications: kidney disease.
These are agents acting on the smooth muscles of the arterioles of the systemic blood flow.
Classification:
A) funds that do not affect ion channels:
- Direct vasodilators: dibazol, papaverine.
B) Means affecting ion channels:
- Calcium channel blockers: verapamil, diltiazem.
- Potassium channel activators: diazoxide, minoxidil.
Calcium channel blockers - reduces the penetration of calcium into myofibrils, reduces the activity of ATP-ase. They relax muscle fibers, improve coronary blood flow, supply the heart with oxygen, expand peripheral vessels, and lower blood pressure. The effect develops gradually. Antiarrhythmic action.
Side effects - nausea, dizziness, constipation.
Contraindications: hypersensitivity, severe hypotension, myocardial infarction.
Potassium channel activators - open potassium channels, hyperpolarization of the membrane of smooth muscle cells, a decrease in the intake of calcium into the cell, a decrease in blood pressure.
Side effects - facial hirsutism, edema.
Contraindications: myocardial infarction, acute cerebrovascular accident, ischemic heart disease.
Comparative evaluation:
Dibazol - hypotensive activity is very moderate, the effect is short-lived.
Diazoxide - affects mainly resistive vessels, inhibits the work of the heart, with enteral administration, the decrease in blood pressure occurs more gradually.
4. Antibiotics of the tetracycline and chloramphenicol group. Classification. Mechanism of action. The nature of the action. Spectrum of action. Indications for use. Side effects. Contraindications Comparative evaluation.
Classification: Tetracyclines: natural (tetracycline) and semi-synthetic (doxycycline, morphocycline, metacyclin). Levomycetin belongs to nitrobenzenes.
Mechanism: inhibit protein synthesis.
Mode of action: bacteriostatic.
Spectrum: wide - gram (+) (-), suppresses aerobic and anaerobic bacteria, actinomycetes, legionella, spirochetes, leptospira, mycoplasma, ureaplasma, reketsia, plasmodia; levomycetin has a bacteriostatic effect on streptococci, gonococci, pneumococci, clostridia, anthrax pathogens, diphtheria, plague, whooping cough, salmonella, shigella, brucella.
Indications: rickettsiosis, chlamydial infections, pneumonia, bronchitis, sinusitis, syphilis, leptospirosis, brucellosis, tularemia, cholera, plague, anthrax, typhoid fever, meningitis caused by Haemophilus influenzae.
Side effects: a decrease in hematopoiesis to agranulocytosis, irritate the gastrointestinal tract, teratogenic (tetracyclines), allergies, dysbiosis, candidiasis.
Contraindications: liver, kidney, blood diseases, pregnancy, children under 8 years old.
Doxycycline and metacyclin last longer (up to 12 hours). All are reserve antibiotics (very toxic).
Tetracyclines are very toxic, therefore they are rarely used in children, especially those for 3-5 years. Levomycetin in children under 3 years of age is used to a limited extent, because toxic effects may occur