An Introduction to Pharmacology & Terminology. What is Pharmacology?. Pharmacon = drug or medicine (in Greek terms ) ; Logos= science or learning
What is Pharmacology? • Pharmacon= drug or medicine (in Greek terms) ; Logos= science or learning • Definition:The science that deals with drugs, their nature, actions, mechanism of action, pharmacokinetics, therapeutic and other uses, preparations and administration. • What is a drug? • Derived from the French word Drogue = Dry herb • The drug is any chemical substance when given to the organism alters body functionsby interaction at the molecular level and is used in treatment (therapeutics),prevention, diagnosis of a disease or in prevention of pregnancy. • NB. Drugs will only modify existing cell function but do not create new ones. • What about gene therapy? • an approach to preventing and/or treating disease by replacing, removing or introducing genes or otherwise manipulating genetic material. • So cell functions may be increased, decreased by drugs. • What is your opinion about tea, coffee and smoking? Drugs or not? • What is a pro-drug? It is a drug whichdoes notproduce any pharmacological effect (not active) until it is chemically altered within the body.
Drug Nomenclature • Drugs are named in 3 ways • The full chemical name e.g. Acetyl salicylic acid • Nonproprietary name= Official (in the pharmacoepia) or approved e.g., Aspirin U.S.P • Proprietary name =Manufacture (trade name) e.g., Aspocid, Rivo ( For Acetyl salicylic acid). • Generic name: Salicylates • NB Generic name refers to a class or a genus of compounds e.g. Sulphonamides, barbiturates, penicillins • However, generic is often misused as to mean nonproprietary
Sources of drugs • Drugs are obtained from one of the following sources: • Plant sources:Various parts of the plants may be used e.g., Leaves of belladonna for atropine. • Animal sources: likeinsulin, heparin. • Mineral sources: E.g., Mg sulphate and iodine. • Microorganisms: Fungi and bacteria for antibiotics like penicillin • Synthetic drugs: E.g., Sulphonamides, aspirin. • Semi-synthetic: E.G. Heroin from morphine. (diacetylmorphine) • Biotechnology: Using genetic engineering (gene therapy), human insulin (Recombinant DNA), and growth hormone. Value of studying pharmacology: • Provides sound basis for selection of drugs in therapeutics. • Allows better understanding of drug toxicity. • Allows better understanding of drug interactions.
The chief aspects of pharmacology Pharmacokinetics Is the study of the kineticsof the drugs. It includes drug Absorption, Distribution, biotransformation (Metabolism), and Excretion(ADME) • = Effect of the body on the drug = What happened to drugs inside the body. Pharmacodynamics Is the study of the biochemical, biophysical and physiological effects of the drugs as well as their mechanisms of action. • = Effect of the drug on the body= What drugs do to the organism. E.g. change in cardiac function, Blood pressure, etc Pharmacotherapeutics • Proper selection and use of drugs for the prevention and treatment of diseases. Therapeutic effect is a consequence of a medical treatment of any kind, the results of which are judged to be desirable and beneficial. • We give the drug to produce the desired effect on certain tissue / organ or function in an appropriate dose.
4. Toxicology: Describes the adverse effects and toxicityof drugs. • Adverse reaction: A term used for harmful or seriously unpleasant effects of a drug occurring at doses used for therapeutic, prophylactic, diagnostic purposes and which call for reduction of dose, drug withdrawal and/or immediate treatment. • Adverse reactions include: • Side effects: They are unavoidable part of the pharmacologic actions of the drug, for a specific indication, at therapeutic doses. • E.G. Sedation with antihistamines • Overdosage toxicity: These occur at high dosesand their incidence increases as the dose level is increased • Allergic reactions: Not dose-related, usually induced by prior contact with the drugs that act as antigens. • Drug abuse: A special form of toxicity, is the use for non therapeutic purposeof drugs that act on CNS. This misuse of drug leads to dependence. E.g. Heroin, Morphine. Contd…..
Special Forms of Adverse reactions of drugs • A. Iatrogenic diseases:Are drug-induced diseases. • A drug prescribed for a disease causes another disease. • E.g. Drug-induced asthma, Peptic ulcer, Parkinsonism. • B. Teratogenesis: (Teratos= Monster: genesis= Production) = Fetal abnormalities. It can be caused by somedrugs when given early in pregnancy (3-10W) Intrauterine life. • E.G. Cytotoxic drugs, Tetracyclines, smoking. • 5. Contraindications: For whom, the drug is forbidden to be prescribed because it will be harmful for them • 6. Drug interactions: They are pharmacological responses which cannot be explained by the action of one drug but are due to multiple drugs acting concurrently. • Drug interactions may be desired or undesired, beneficial or harmful
Sources of drug information • Pharmacology text books. • Medical journals. • Pharmacopoeias. • What is the pharmacopoeia?= Formulary • Is an official (published by authorized body) book containing a selected list of widely used drugs and medicinal preparationswith descriptions of their physical propertiesand tests for their identity, purity, potency, safety. It also contains a description of the standard preparations of the drugs and their average doses (minimal effective dose, Maximum tolerated dose). Drugs are introduced according to their therapeutic usefulness. • I.E= Definition, potency, and purity of drugs are regulated by law. These data are published in books known asPharmacopoeia • The majority of nations publish their own pharmacopoeia e.g., • USP= United states Pharmacopoeia • BP= British Pharmacopoeia • EP= Egyptian Pharmacopoeia • SAP= Saudi Arabia Pharmacopoeia
Types of drug regulation • Over-the counter drugs (OTC) • Prescription drugs • Controlled drugs e.g. Morphine & Cocaine • Experimental drugs E.g. Anticancer drugs DR Raza
Some terminology used in studying pharmacology • An antibiotic; A chemical substance synthesized by living micro-organisms used to kill or stop growth of other microorganisms. E.g. Penicillin • A chemotherapeutic agent; A synthesized chemical substance used to stop the growth or kill microorganisms. E.g. Sulpha • Chemotherapy: is the use of chemical substances to treat infections caused by micro-organisms or kill cancer cells • Antibacterial: A chemical substance used to kill or stop growth of bacteria. It may be an antibiotic or a chemotherapeutic agent.
Some terminology used in studying pharmacology • Antipyretic; A drug which lowers elevated body temperature • Analgesic: A drug which relieves pain or headache • Diuretics; Drugs which increase rate of water and solute production (volume of urine) • Sedatives / hypnotics; Drugs which sedate the patient and could induce hypnosis. • Antispasmodics; Drugs which relieve smooth muscle spasm (e.g. colic) • Antiemetics; Drugs which prevent and treat nausea and vomiting
How can you give the drug to your patient (administration)? • Enteral • Oral • Sublingual (SL) • Buccal • Rectal • Parenteral • Intradermal (ID) • Subcutaneous (SC) • Intramuscular (IM) • Intravenous (IV) • Intra-arterial (IA) • Intrathecal: in anesthesia (IT) • Intraperitoneal (IP) • Intrapleural • Intra-articular: in joints • Inhalation • Topical • Skin, ear, eye, nose, vagina, respiratory tract. DR Raza