Introduction To Pharmacology PDF

INTRODUCTION TO PHARMACOLOGY Textbook: Focus on nursing pharmacology, 2011, Amy Karch, Lippincott Pharmacology for the Health Care Professions, Christine M. Thorp. 2008 Learning Objectives: After reading this section, you will be able to answer the following questions : Defin...

INTRODUCTION TO PHARMACOLOGY Textbook: Focus on nursing pharmacology, 2011, Amy Karch, Lippincott Pharmacology for the Health Care Professions, Christine M. Thorp. 2008 Learning Objectives: After reading this section, you will be able to answer the following questions : Define pharmacology Why we study pharmacology? Where did the world pharmacology come from? Why nurses and other health professionals need to have knowledge of pharmacology? BACKGROUND: Definition of Pharmacology A drug is a chemical substance that is administered to the body to cause changes. Pharmacology can be defined as the study of drugs and their interaction with living organisms. The suffix “pharmaco-” comes from the Greek pharmakon, which means remedy and poison.  BACKGROUND: Definition of Pharmacology Pharmacology is a broad term that describes the study of all aspects of drugs:  Sources, origins & chemical structure  Administration  The various processes that occurs after their administration like absorption, distribution, actions, metabolism, and excretion (pharmacokinetics).  The effect of drugs on various body cells, organs and systems (Pharmacodynamics)  BACKGROUND: Drug effects The body functions through a system of sophisticated chemical reactions and processes In the body, drugs cause a sequence of intended and unintended chemical and biological changes. The intended changes caused by the drugs are known as therapeutic actions The unintended actions are known as side effects or untoward effects. Why do healthcare professionals need to learn Pharmacology? For healthcare professionals, it is important to understand how drugs affect the body and apply that knowledge in their daily healthcare practice. Healthcare professionals are involved in:  administering drugs to patients,  teaching patients about the drugs they use,  assessing the actions of the drugs  intervening to minimize the side effects  monitoring the overall patient care plan. SOURCES OF DRUGS After reading this section, you will be able to answer the following questions: What are the different sources of drugs? How genetic engineering improved drugs obtained from animal sources? Can you give few examples on drugs obtained from natural sources? SOURCES OF DRUGS:  Drugs are obtained from natural and synthetic sources.  In either cases, the chemical should demonstrate efficacy and safety to qualify as a drug. SOURCES OF DRUGS: Natural drugs Obtained from: plants, animals, and/or inorganic compounds. Plants Plants and their parts have been and still being used as an important sources of drugs for prehistoric and modern human beings. Examples: morphine, codeine, and digoxin. SOURCES OF DRUGS: Natural drugs Animal products Before the advent of genetic engineering, proteins and hormones like insulin, thyroid, and growth hormone were obtained from animals and used to replace missing and/or faulty human proteins and hormones. Today, chemical synthesis and genetic engineering have produced purer and safer products compared to those obtained from animals previously. Inorganic compounds Many naturally occurring salts of elements have therapeutic value in humans. Examples include salts of aluminum, magnesium, and iron. SOURCES OF DRUGS: Chemical synthesis Numerous drugs are chemically synthesized on larger scale after chemicals from plants, animals, and the environment showed therapeutic effects. Table 1.1 provides summary of drug products and their origins. NAMING OF DRUGS After reading this section, you will be able to answer the following questions: How many names a drug can possess? Define the chemical, generic, trade and brand names of a drug?  Naming of drugs  Chemical name: reflects drugs’ chemical structure or formula.  Generic name (international nonproprietary name (INN)) : designated by Pharmaceutical companies a for the drug when the company submits an application for to obtain approval from the health authorities.  Trade names: used by Pharmaceutical companies to register for their drug products.  Brand name: The trade name by which the drug was marketed by the first pharmaceutical company that developed it.  p-isobutylhydratropic acid Chemical name Ibuprofen Nurofen®, Advil®, Morin®, Brufen® Generic name Trade names 16  Activity 1.1 You may collaborate with your colleague to perform this activity Look at Figure and note the:  Active ingredient in each product  Pharmaceutical dosage form  Strength of each dosage form  Number of units in each packet  Trade names  Manufacturers LEGAL ASPECTS OF DRUG USE After reading this section, you will be able to answer the following questions:  What authorities approve drugs for human use?  How drug use is regulated?  When drugs can be used in pregnant women? LEGAL ASPECTS OF DRUG USE In each country, health regulatory authorities regulate the development, approval, and use of drugs within their jurisdictions, Examples:  Food and Drug Administration (FDA) in the United States  European Medicines Agency (EMA) in the European Union  Ministry of Health in Palestine. LEGAL ASPECTS OF DRUG USE Drugs are categories into Prescription drugs Over-the-counter (OTC) drugs Controlled drugs. Prescription drugs They need a valid prescription from a health professional who is authorized to prescribe them. Examples :  Anti-hypertensive drugs.  Anti- diabetic drugs.  Drugs for Asthma.  Drugs for inflammatory diseases …. etc Over-the-counter (OTC) drugs Can be obtained for self- medication without a prescription. considered safe when used as directed. Examples: anti-burn creams, sunscreens, mild analgesics, anti-pyretics , gels for muscle pain.  Controlled drugs Possess considerable abuse potential. These drugs are prescribed for certain patients using specified prescriptions designated for controlled drugs. Examples: Narcotics, sedative- hypnotics. Drug use in pregnancy  Health regulatory authorities like the FDA has categorized drugs into 5 categories  They indicate the risk to cause teratogenicity.  These categories are presented in Table 1.2.  Obtaining more innformation on drug use  As the world of drug therapy changes continuously, healthcare professionals need to have access to information on drugs like their therapeutic actions, dosage, indications, contraindications, warnings, cautions, available dosage forms, pharmacokinetics, side effects, drug-drug and drug-food interactions.  Healthcare professionals might obtain authentic and updated information from the drug labels, package inserts (leaflets), drug guides, reference books, scientific journals, and authentic websites. Drug labels  Drugs are labeled with information to help healthcare professionals and consumers use the drug.  Labels often identifies:  the brand and generic names  dosage form and strength  route of administration  special warnings (if any). Package inserts (leaflets)  Manufacturers include package inserts (leaflets) inside the drug package.  Package inserts sometimes contain complete information about the drug,  its chemistry & pharmacological class  therapeutic actions, indications  Dosage & alternative dosage forms,  Route of administration  Pharmacokinetics  Side effects, contraindications, warnings & cautions  Interactions  OBTAINING MORE INFORMATION ON DRUG USE Drug guides Drug guides provide complete information on drugs available in the country. Drug monographs provide information on drugs, pharmacological classes, therapeutic actions, indications, dosages, alternative dosage forms, routes of administration, pharmacokinetics, side effects, contraindications, warnings, cautions, and interactions. Reference books There are many pharmacology and pharmacotherapy reference books that contain a variety of exhaustive information on drugs. ( examples : drug handbook , lipincott …. )  OBTAINING MORE INFORMATION ON DRUG USE Scientific journals Scientific journals provide reviews and news that can serve as a useful sources of information on drugs ( examples : BMJ , lancet …. ) Authentic websites There are many authentic website on which information and data relevant to drugs are continuously kept up-to-date and scientifically reviewed for quality. ( Examples: medscape , drug.com …..)