Pharmacology Introduction (By Dr Takele Beyene, DVM,MSc,PhD,@AAU)

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  • 1. ADDIS ABABA name,the lamb of God! No terror in gcs UNIVERSITY 1SCHOOL OF VETERINARYMEDICINEDEPARTMENT OF BIOMEDICALSCIENCES Veterinary Pharmacology and HolyTherapeutics I (BMSC 311 ) Lecture 1 Spiri t GOD Father Jesus Takele Beyene (B. Pharm, MSc)
  • 2. 2 I. General Pharmacology No terror in gcs name,the lamb of God!
  • 3. 1. INTRODUCTION3 Learning Objectives  By the end of this lecture you will be able to :  Define certain terminology: pharmacology, drugs…  Identify the goal of studying Pharmacology  Explain the rational use of drugs  Discuss drug characteristics :  sources, classification, names ; ..  Discuss Routes of drug administration No terror in gcs name,the lamb of God!
  • 4. What is pharmacology? The word pharmacology comes from Greek: Pharmakon - drug and logos - knowledge Pharmacology is the study of drugs and their interaction at any cellular level with the body’s components. The study of substance/s that interact with living systems through chemical processes specially by binding to regulatory molecules and activating or inhibiting normal body process4 No terror in gcs name,the lamb of God!
  • 5. The main scope of pharmacology is to study the action of drugs on the living cells and the mechanism by which such effects are produced. Pharmacology: is the science dealing with substances used to prevent, diagnose and treat diseases i.e. studying their nature, pharmacokinetics, pharmacodynamics, therapeutic uses, adverse reactions, preparations and administration.5 No terror in gcs name,the lamb of God!
  • 6. Drugs are biologically active chemicals that interact with a biological systems and somewhat modify the env’t around the cell and thus produce some desired effects: used in the treatment, prevention, or diagnosis of disease, or prevention of pregnancy.6 No terror in gcs name,the lamb of God!
  • 7. Major Uses of Drugs  1—Symptomatic:7  Relieve disease symptoms e.g. Aspirin...  2—Preventative:  To avoid getting a disease e.g. Hepatitis B vaccine, Flu vaccine.  3—Diagnostic:  Help determine disease presence e.g. Radioactive dyes.  4—Curative:  Eliminate the cause of the disease e.g. antibiotics.  5—Health Maintenance:  Drugs for weight control.  6—Contraceptive:  Preventative No terror in gcs name,the lamb of God!
  • 8. Rational use of drugs8  we usually consider the following  Effectiveness  Indications  Action  Safety  Contraindications  Adverse drug reactions  interactions with other drugs & food  Route & dosage  Other  Cost  availability of the drug  Patient compliance No terror in gcs name,the lamb of God!
  • 9. Rational use of drugs9  All members of health care team must exercise care to promote therapeutic effects and minimize drug induced harm Risk-benefit No terror in gcs name,the lamb of God! ratio
  • 10. 10 Concept no 1 Almost ALL DRUGS ARE POISONS The only thing that determines if a drug provides a benefit or kills a patient is how we administer it No terror in gcs name,the lamb of God!
  • 11. Concept II : Our Therapeutic Goal11 To achieve drug concentrations at the site of action (target tissue)…that are sufficiently high enough…to produce the intended effect without producing adverse drug reactions(or with minimal adverse reactions). No terror in gcs name,the lamb of God!
  • 12. Seven Rights of Medication Administration12  Right Medication  Right Dose  Right Time  Right Route  Right Patient  Right Documentation  Right DATE No terror in gcs name,the lamb of God!
  • 13. The chief aspects of pharmacology include: 1. Pharmacokinetics 2. Pharmacodynamics 3. Pharmacotherapeutics13 No terror in gcs name,the lamb of God!
  • 14. 1.Pharmacokinetics It explores the factors that determine the r/s b/n drug dosage and the time varying conc. of drug at the site of action. What the body does to the drug. is the study of drug absorption, distribution, biotransformation and excretion. 2.Pharmacodynamics Concerned with the r/s b/n the drug conc at its site of action and the magnitude of effect that is achieved. is the study of the biochemical ,physiological effects of drugs as well as their mechanisms of action14 What the drug does to in gcs body. lamb of God! No terror the name,the
  • 15. 3.Pharmacotherapeutics This deals with the proper selection and use of drugs for the prevention and treatment of disease. Pharmacogenetics The study of genetically inherited conditions that : 1.Affect the way drugs act on the body. 2.Modify the way the body acts on drugs.15 No terror in gcs name,the lamb of God!
  • 16. Drug characteristics16  Sources  Naming  Classification No terror in gcs name,the lamb of God!
  • 17. Sources of Drugs 1-Plant sources  various parts of plants may be used as sources of drugs: alkaloids, glycosides, oils (fixed or volatile),.. e.g. Leaves of belladonna for atropine, Bark of cinchona for quinine and quinidine. 2-Animal sources hormones, vitamins, vaccines and heparin. Insulin from pancreas of different animals e.g. cattle or pig, steroids 3-Mineral sources: e.g. Magnesium sulphate , kaolin and iodine17 No terror in gcs name,the lamb of God!
  • 18. 4-Microorganism: Fungi and bacteria isolated from soil are important sources of antibiotics e.g. penicillin 5-Synthetic drugs: Many drugs are produced in the laboratory e.g. CAF, sulphonamide, barbiturates, aspirin 6- Semisynthetics- some penicillins: amoxicillin 7-Biotechnology: by recombinant DNA technology; insertion of the desired DNA into another DNA of a living cell to form recombinant DNA18 e.g. Human insulin and of growth hormone have No terror in gcs name,the lamb God! successfully been produced by genetic engineering
  • 19. Drug Nomenclature19 1. Chemical name  The drug’s chemical composition and molecular structure 2. Generic name (non-proprietary name)  The name of a drug that can be used by any producer 3. Trade name (proprietary name)  The drug has a registered trademark; use of the name restricted by the drug’s owner (usually the manufacturer) No terror in gcs name,the lamb of God!
  • 20. Drug Nomenclature…cont’d20 Chemical name Generic Trade name name Acetylsalisylic acid Aspirin Jusprin,aspocid,… Albendazole Alzole, Albenza N-acetyl-p- Paracetamol Panadol,® aldol® aminophenol 2-(p-isobutylphenyl) ibuprofen Motrin® propionic acid No terror in gcs name,the lamb of God!
  • 21. Classification of Drugs  Therapeutic Classification Is based on what the drug does clinically • For example: – Anticoagulants – Antidepressants – Antineoplastics  Pharmacologic Classification  More specific than therapeutic classification  Requires understanding of biochemistry and physiology  Based on how the drug produces its effect at molecular, tissue, or body-systems level • e.g. CCBs, ACE, Proton-pump inhibitors (PPI’s).21 No terror in gcs name,the lamb of God!
  • 22. Further Classification of drugs Therapeutic action e.g: Antibiotics sub class. in view of Cell - wall inhibitors Mechanism Chemistry β-lactam antibiotics o Penicillins o Cephalosporins spectrum Cephalosporins are classified as 1st , 2nd , 3rd and 4th generations22 No terror in gcs name,the lamb of God!
  • 23. Routes of drugs administration23  The route of adm is determined by: 1. Drug property: water or lipid solubility, ionization, etc. 2. Therapeutic objectives  Desirability of onset of action  Need for long term adm  Restriction to local site 1-Administration for local effects 2-Administration for systemic effects No terror in gcs name,the lamb of God!
  • 24. 1-Administration for local effects24  The drug is applied directly to the desired site in an adequate concentration in suitable vehicle.  This achieved by one of the following means: A-Topical application:  The drug is applied to the skin or to mucous membranes in the form of powders, No terror in gcs name,the lambointments, lotion, creams, of God!
  • 25. Administration for local effects…cont’d25 B-Injection:  The drugs are injected around sensory nerve terminals(Infilteration anaesthesia) or in joints (Intraarticular) e.g. injection of corticosteroids in rheumatoid arthritis c)Inhalation: Drugs may be administered by aerosol  e.g. salbutamol in bronchial asthma No terror in gcs name,the lamb of God!
  • 26. 2. Administration for systemic effects:26  mean drugs go to general circulation after absorption. No terror in gcs name,the lamb of God!
  • 27. Individual routes of27 administration A. Enteral/ Gastrointestinal tract: oral, sublingual, rectal B. Parenteral C. Others  Inhalation  Epithelial surfaces  Skin/topical  Eye/corneal  Nasal mucosa  Transdermal No terror in gcs name,the lamb of God!
  • 28. A. Enteral28 1-Oral administration:  the most convenient, safest, economical and most commonly used.  Considered as traditional  given orally to produce either a systemic effect or only a local effect on the gut.  Before entering the bloodstream, an oral drug must be released from the dose form, transported across the GI tract, and passed through the liver  usually have slower onset of action, longer duration of activity, and absorption rates  Oral drugs may be tablets, capsules, boluses, powders, solutions, suspensions, or emulsions No terror in gcs name,the lamb of God!
  • 29. Enteral.. Cont’d29 Criteria of oral drug  The drug should be palatable,  non-irritant,  stable at the pH of the intestinal tract and  unaffected by digestive juices. No terror in gcs name,the lamb of God!
  • 30. Enteral.. Cont’d Disadvantages of oral route30 1. The onset of action is delay in comparison with parenteral  The route is thus unsuitable in emergency situations 2. Irritant drugs cannot be administered by this route 3. It is impractical in unconscious ,uncooperative patients 4. Drugs can be destroyed by digestive enzymes (insulin) 5. Some drugs are not absorbed from the gut(aminoglycoside antibiotics e.g. streptomycin). 6. Some drugs are absorbed from gut but inactivated in the liver before reaching to general circulation ( first pass effect). No terror in gcs name,the lamb of God!
  • 31. Enteral…cont’d31 First-pass Effect No terror in gcs name,the lamb of God!
  • 32. Enteral.. Cont’d 2-Sublingual administration32  The drug is given in the form of a small tablet placed beneath the tongue.  The drug should be palatable, soluble,and effective in small dose.  e.g. isoprenaline in bronchial asthma and glyceryl trinitrate in angina No terror in gcs name,the lamb of God!
  • 33. Enteral.. Cont’d33 Advantages of the sublingual route a)Rapid absorption b)Avoiding destruction of drugs by digestive juice or inactivation by liver before going to circulation. No terror in gcs name,the lamb of God!
  • 34. Enteral.. Cont’d 3-Rectal administration34 The drug is given by suppository or enema. Advantages of rectal route a)Drugs irritant to stomach can be given by suppository b)The route can be used when cooperation is lacking ( In children). c)The effect of digestive enzymes is avoided d)Bypass the first pass effect. of God! No terror in gcs name,the lamb
  • 35. B. Parenteral administration35  The two major parenteral routes are: 1. Subcutaneous implantation 2. Injection  Intramuscular IM.,  Intravenous IV.,  Subcutaneous SC.,  Intraperitonial IP.,  Intracardiac, and  intrathecal/intraventricular No terror in gcs name,the lamb of God!
  • 36. Injectable Routes of Administration (IV)36  Drugs given IV have  rapid onset of action, higher initial body levels of drug, and shorter duration of activity  IV injection techniques include: bolus administration, intermittent therapy, and infusion of fluid  In most cases, IV drugs should be given slowly  All air bubbles must be removed from the drug before administration  to avoid causing air emboli and tissue damage No terror in gcs name,the lamb of God!
  • 37. Injectable Routes….(IM)37  Drugs given IM have  relatively rapid onset of action and longer duration of activity than IV drugs  Absorption rate depends on drug formulation  IM-injectable drugs may be in a substance that delays absorption; these are referred to as repository or depot preparations  IM drugs can be in aqueous solutions or suspensions  Solutions are clear liquids that contain one or more solvents and one or more solutes  Suspensions are liquid preparations that contain solid drug particles suspended in a suitable medium No terror in gcs name,the lamb of God!
  • 38. Injectable Routes…. (SC)38  Drugs given SC have  slower onset of action and longer duration of activity than IV and IM drugs  Absorption rate may be altered by the vehicle in the preparation  Larger amounts of solutions can be given; amount given should be based on animal species involved  Pellets can also be implanted into the subcutaneous space  The rate of absorption of SC fluid can be manipulated by temperature  Applying heat to the area increases the rate of absorption  Applying cold to the area decreases the rate of absorption No terror in gcs name,the lamb of God!
  • 39. Injectable Routes….intra-39 arterial(IA)  Restrict drug to specific organ E.g. for the t/t of liver, head and neck tumor  Diagnostic agents are sometimes adm via this  Require great care and reserved for expertise No terror in gcs name,the lamb of God!
  • 40. C. Others40  Inhalation:  provides rapid delivery of a drug across the large SA of respiratory m/m  Produce rapid effect as almost as IV  Used for gases (anaesthetics), or dispersed in an aerosols  Application to epithelial surfaces:  E.g. skin, cornea(eye), Vagina, nasal mucosa  Transdermal: application within skin usually via No terror in gcs name,the lamb of God!
  • 41. 41  Very Important Info! No single method of drug administration is ideal for all drugs in all circumstances No terror in gcs name,the lamb of God!
  • 42. Common Terminology42 1. STAT  Immediately 2. OD  Daily 3. BD  Twice a day 4. TDS  Three times a 5. QID day 6. ON (Nocte)  Four times a 7. PRN day  On night  As needed No terror in gcs name,the lamb of God!
  • 43. Common terminology…..43 1. PO  Oral 2. ID  Intradermal 3. SC  Subcutaneous 4. IM  Intramuscular 5. IV  Intravenous No terror in gcs name,the lamb of God!
  • 44. Others terminology44 1. Ac  Before meals 2. Dil  Dissolve, dilute 3. Gtt  Drop 4. H  An hour 5. Hs  At bedtime 6. Pc  After meals 7. Q  Every 8. qAM  Every morning 9. qh  Every hour 10. Q2h Every 2 hours 11. Sos If it is needed No terror in gcs name,the lamb of God!