Pharmacology Preliminary PDF

TRANS FOR PHARMACOLOGY PRELIM THE EVOLUTION OF MEDICINAL DRUGS PHARMACOLOGY Definition: Study of substances that interact with living systems through chemical processes, especially binding to regulatory molecules and activating or inhibiting body processes. Orig...

TRANS FOR PHARMACOLOGY PRELIM THE EVOLUTION OF MEDICINAL DRUGS PHARMACOLOGY Definition: Study of substances that interact with living systems through chemical processes, especially binding to regulatory molecules and activating or inhibiting body processes. Origin of "Drug": Comes from the word CLAUDE BERNARD (1813-1878) “drogue” (dry herb). Father of Modern Experimental Medicine. Expanded on Magendie’s work. Identified specific sites of drug action in the HISTORY OF MEDICINAL DRUGS body. Started the field of experimental pharmacology. Natural Healing Knowledge: Grew from trial and error. ALEXANDER FLEMING (1881-1955) Control of Medical Treatment: Historically controlled by religious leaders. Discovered the antibiotic penicillin from the Pharmakos: Greek word meaning magic spell, mold Penicillium notatum in 1928 by chance. remedy, or poison. His accidental discovery occurred after returning from vacation and noticing that mold inhibited KEY FIGURES: bacterial growth on a petri dish. HIPPOCRATES (460-377 B.C.) Alexander Fleming, a professor of Bacteriology at St. o "Father of Medicine" Mary's Hospital in London, didn't do a great job of o First to separate medicine from religion cleaning his laboratory before heading out on vacation in and superstition. 1928. When Fleming came back, he began cleaning the o Proposed that disease had natural petri dishes on which he was experimenting with causes. bacteria. On one dish, however, he found a mold growth. o Used dissection to study human organ In the area around the mold growth, there was no functions. bacteria. There was bacteria in other parts of the petri PEDANIUS DIOSCORIDES dish, but the mold was sitting in an area alone. Fleming o Greek physician who researched plants had a "eureka!" moment, as he had just accidentally and their uses. discovered an antibiotic. o de Materia Medica: Supreme authority on medicine and pharmacology for nearly 1500 years. o Described and classified 600 plants by substance, not by diseases treated. PARACELSUS (1493-1541) o Pioneered use of chemicals and minerals in medicine. o Advocated for individual drugs over mixtures and potions (opposed polypharmacy). FRANCOIS MAGENDIE o French physiologist and pioneer of experimental physiology. o Known for describing the foramen of Magendie and Magendie sign. DRUG NAMES AND CLASSIFICATIONS o Introduced new drugs like morphine, codeine, and quinine into French Chemical Name: Reflects chemical makeup (e.g., medicine. Immunoglobulin G1). Generic Name: Name given by the manufacturer (USAN); nonproprietary and not protected by trademark. Brand Name: Trade name, copyrighted and used exclusively.  Dissolution: A drug in solid form (tablet or capsule) must disintegrate into small particles to dissolve into a liquid form. Excipients: Fillers and inert substances that allow the drug to take on a particular size and shape and enhance drug dissolution. DISINTEGRATION Breakdown of a tablet into smaller particles. CLINICAL TRIALS DISSOLUTION Phase I: Studied in 20-100 healthy people. Phase II: Studied in patients with the condition Dissolving of smaller particles in the GI fluid intended for treatment. before absorption. Phase III: Compared to commonly used Example: Enteric-coated drugs resist treatments. disintegration in the gastric acid of the stomach. Phase IV: Continued testing after approval for marketing. PHARMACOKINETIC PHASE The process of movement to achieve drug action (4 phases): o Absorption o Distribution o Metabolism o Elimination ABSORPTION Movement of drug particles from the GI tract to body fluids by passive absorption, active absorption, or pinocytosis. o Passive absorption: Occurs mostly by INTRODUCTION DRUG ACTION diffusion. o Active absorption: Requires a carrier 3 PHASES OF DRUG TAKEN BY MOUTH such as an enzyme or protein to move the drug against a concentration 1. Pharmaceutic - Dissolution gradient. 2. Pharmacokinetics - Process of drug movement o Pinocytosis: Cells carry the drug across (4 phases) their membrane by engulfing the drug o Study of drug actions as they move particles. through the body; the way the body absorbs, distributes, metabolizes, and REMEMBER: Drugs that are lipid-soluble and non-ionized excretes drugs; a mathematical study of are absorbed faster than water-soluble and ionized drugs based on time and dose in the drugs. body and how the body reacts to them. 3. Pharmacodynamics - Biologic/physiologic response FDA CATEGORIZATION OF DRUGS FOR USE IN o Study of the mechanisms of action of PREGNANCY drugs within the body and how drugs produce their effects in the body. Category A: Adequate, well-controlled studies in pregnant women have not shown an increased risk of fetal abnormalities. PHARMACEUTIC PHASE Category B: Animal studies have revealed no evidence of harm to the fetus, but there are no The 1st phase of drug action. adequate studies in pregnant women. Or Animal studies have shown an adverse effect, but adequate and well-controlled studies in  pregnant women have failed to demonstrate a Antagonist: A drug that binds to a receptor site risk to the fetus. and blocks the action of the endogenous messenger or other drugs. PHARMACOKINETICS The activity of a drug within the body over time. Study of mathematical relationships among absorption, distribution, metabolism, and excretion of individual medicines over time. LIBERATION Also known as the pharmaceutic effect, relating to the dosage form being used. After liberation from the dosage form, each drug has its own unique ADME. Absorption Process whereby a drug is transferred from its site of entry into the body to the circulating fluids (lymph and blood) for distribution. o Rate depends on the route of administration, blood flow through tissue, and the solubility of the drug. Distribution Process by which a drug moves from the blood to other body fluids and tissues and ultimately to its sites of action (receptors). Metabolism Also called biotransformation; the process by which the body inactivates drugs. The liver is the BASIC CONCEPTS OF PHARMACOLOGY primary site of metabolism. PHARMACODYNAMIC PHASE Elimination/Excretion Receptors Clearance is the rate at which a drug is eliminated from a specific volume of blood per A receptor is a protein molecule on the surface or within a cell that recognizes and binds with unit of time. specific molecules, producing some effect within the cell. o Receptor site may have specificity. DISCUSSION o Affinity: Strength by which a chemical messenger binds to its receptor site or Primary sites of elimination in the body: The cell. kidney and liver, but drugs can also be exhaled by the lungs or excreted in perspiration. MECHANISMS OF DRUG ACTION Agonist: A drug that binds to a receptor site and triggers the cell’s response. HALF-LIFE Indications: Diseases or symptoms for which the drug is known to be beneficial. The amount of time required for 50% of the drug Contraindications: Diseases or symptoms for to be eliminated from the body. which the drug may do harm. o Essential in determining the dosage Side Effects: Secondary responses to a drug interval of a drug. other than the primary therapeutic effect. ADVERSE DRUG REACTIONS COMMON DRUG RELATIONSHIPS Defined by WHO as any noxious, unintended, Additive Effect: Two drugs with similar actions and undesired effect of a drug occurring at doses are taken for a doubled effect (e.g., used for prophylaxis, diagnosis, or therapy. Propoxyphene + aspirin = added analgesic "Right drug, right dose, right patient, bad effect." effect). (Should not be confused with Adverse Drug Synergistic Effect: Combined effect of two drugs Events.) is greater than the sum of each (e.g., Aspirin + codeine = much greater analgesic effect). Antagonistic Effect: One drug interferes with the action of another (e.g., Tetracycline + antacid = ALLERGIC REACTION (HYPERSENSITIVITY REACTION) decreased absorption of tetracycline). Incompatibility: The first drug is chemically Occurs in patients previously exposed to a drug, incompatible with the second drug, causing leading to antibody development. On re- deterioration when mixed (e.g., Ampicillin + exposure, antibodies cause a reaction, Gentamicin = Ampicillin inactivates Gentamicin). commonly seen as raised, irregular patches on the skin (urticaria or hives). DISCUSSION CARCINOGENICITY Why is it important for the pharmacy to have a complete list of all of the prescription drugs, The ability of a drug to induce cells to mutate and OTC medications, vitamins, and herbal become cancerous. Many drugs with this remedies that a patient is taking? potential are tested in several animal species Answer: A complete list helps healthcare before human investigation. professionals identify potential drug interactions. DISPENSING OF PHARMACOLOGIC AGENTS TERATOGENICITY A drug that induces birth defects. Fetal organs are susceptible to malformation if exposed during pregnancy. DRUG EFFECTS Beneficial Responses Therapeutic Effect: The action for which the drug is prescribed. Local Effect: Confined to a specific body part. Systemic Effect: Generalized, all-inclusive effect on the body. Drug Considerations by Healthcare Practitioners Dosage Forms and Routes of Administration Per oral (PO, by mouth) Dosage Route – Oral (swallowed) – Sublingual (under the tongue) – Buccal (dissolves in the cheek) Parenteral Dosage Route – Intravenous (vein) – Intra-arterial (artery) – Intracardiac (heart) – Subcutaneous (beneath the skin) – Intramuscular (muscle) – Intradermal Topical Dosage Route – Transdermal (skin surface) – Conjunctival (conjunctiva) or Intraocular (eye) – Intranasal (nose) – Aural (ear)/OTIC – Intrarespiratory (lung) – Rectal – Vaginal – Urethral Per oral (PO, by mouth) Dosage Forms o Tablets, capsules, solutions, syrups, elixirs, suspensions, gels, powders, lozenges (harden base of sugar, water, and flavors), tincture o Chewable tablets, scored tablets (easily broken), effervescent tablets, enteric tablets, caplets, soft gelatin o Liquid sprays Parenteral Dosage Forms – Solutions – Suspensions (suspended in a liquid base, shake) Topical Dosage Forms o Ointments, creams, pastes, powders, aerosols, lotions, transdermal patches, sprays, inhalants, suppositories, enemas, emulsions, sponges, gels FACTORS THAT INFLUENCE DRUG ACTION Age o Pediatric patients and elderly patients may need a reduced dose due to smaller size or liver metabolism issues. Disease oSpecific diseases may hinder the pharmacokinetic process of some drugs. Mental State, Genes, Gender CONSIDERATIONS FOR ELDERLY PATIENTS Physiologic Function Changes: Optic Auditory  Gastrointestinal Allergic Diseases Pulmonary Cardiovascular Allergic rhinitis (Hay fever) Urinary Allergic dermatitis, eczema Hormonal Contact dermatitis Composition of the body Urticaria (hives) Drug Therapy for Allergies: IMMUNIZATION Free environment of allergens (if possible) A process by which resistance to an infectious disease is Corticosteroids induced or augmented. Short-term relief with antihistamines Types of Immunity: Long-term desensitization programs Active immunity o Activated when a pathogen such as a bacterium or virus invades the body. Prostaglandins Passive immunity o Occurs when an individual receives Mediators of several physiologic processes antibodies against a particular pathogen Actions: from another source. o Endocrine system o Cardiovascular system o Gastrointestinal system o Pulmonary system ENDOGENOUS CHEMICALS THAT AFFECT DRUG o Inflammatory ACTION AND RESPONSE Histamine Receptors: o H1 receptors mediate contraction of Teaching Patients Medication Management smooth muscle of the bronchi and Goal: Compliance intestine. A patient’s adherence to the dose schedule and o H2 receptors mediate histamine’s action other specific requirements of the drug regimen. on gastric secretion and cardiac acceleration. Drugs that block histamine receptors: o Antihistamines (block H1 receptors) o H2 blockers: ▪ cimetidine (Tagamet) ▪ ranitidine (Zantac) ▪ famotidine (Pepcid) ▪ nizatidine (Axid) Teaching Patients Medication Management