PHRLEC-PRELIM-MODULE-1-LESSONS-1-3.docx

**PHARMACOLOGY- PRELIM** **[Module 1- Introduction to Pharmacology and Drugs]** **[Lesson 1: Fundamental Concepts of Pharmacology]** **Terms:** - **Drugs:** chemicals which when absorbed, exhibit specific response or action - **Pharmacology:** science which is concerned with the history...

**PHARMACOLOGY- PRELIM** **[Module 1- Introduction to Pharmacology and Drugs]** **[Lesson 1: Fundamental Concepts of Pharmacology]** **Terms:** - **Drugs:** chemicals which when absorbed, exhibit specific response or action - **Pharmacology:** science which is concerned with the history, sources, physical and chemical properties of drugs as well as ways in which drugs affect living systems - **Pharmacogenetics:** study of genetic factors as determinants of drug responses - **Pharmacognosy:** study of drugs derived from natural resources - **Pharmacy:** science of preparing, compounding and dispensing medicines - **Toxicology:** study of harmful effects of drugs on living tissues - **Posology:** the study of dosage or amount of drugs given in the treatment of disease - **Therapeutic effect:** desired or primary\* - **Side Effect:** unintended; secondary effect\*\* - **Drug Allergy:** immunologic reaction to a drug - **Anaphylactic Reaction:** a severe reaction that usually occurs immediately following the drug administration - **Drug Tolerance:** decreased physiologic response to the repeated administration of a drug or chemically related substance\* - **Cumulative Effect:** increasing response to the repeated doses of a drug\*\* **Is Alcohol a Food or a Drug???** - **ALCOHOL:** Is classified as a Central Nervous System Depressant, which mean drinking alcohol slows down brain functioning, neural activity and further reduces the functioning of various vital functions of the body. **Terms:** - **Drug Abuse:** inappropriate intake of a substance either continually or periodically - **Drug Dependence:** refers to person's reliance or a need to take a drug or substance\* - **Addiction:** the tissues come to require the substance for normal functioning\*\* - **Habituation:** the emotional reliance on a drug to maintain a sense of well-being accompanied by feelings of need or cravings for the drug\* - **Controlled Drugs:** drugs that affect the mind or behavior which can be dispensed only with a prescription. - **Idiosyncratic:** drug reaction is different from what is expected\*\* - **Drug Interaction:** effects of one drug are modified by the prior or concurrent administration of another drug\* - **Drug Antagonism:** conjoint effect of 2 drugs is less than the drug acting separately - **Summation:** the combined effect of 2 drugs produces a result that equals the sum of the individual effects of each agent - **Synergism:** the combined effect of 2 drugs is greater than the sum of each individual agent acting separately - **Potentiation:** the concurrent administration of 2 drugs in which one drug increases the effect of the other drug. **Drugs' General Properties** - drugs do not confer any new function on a tissue/ organ in the body - drugs exert multiple actions rather than a single effect - drug interactions result from a physiochemical interaction between the drug and a functionally important molecule in the body **Therapeutic Actions:** - **Palliative:** relieves the symptoms of a disease but does not affect the disease itself. - **Curative:** treats a disease or condition - **Supportive:** sustains body functions until other treatment of the body's response can take over - **Substitutive:** replaces body fluids or substances - **Chemotherapeutic:** destroys malignant cells - **Restorative:** returns the body to health. **Categories of Drug Action:** - **Stimulation:** rate of cell activity or secretion is increased - **Depression:** rate of cell activity or secretion is reduced - **Replacement:** replaces essential body compounds, etc. - **Inhibition:** killing or destroying organisms - **Irritation:** ex. laxatives irritate the inner wall of the colon increasing peristalsis and defecation. **How Are Drugs Classified?** - **Specific Names** - 4-Thia-1-azabicyclo (3.2.0) heptane-2-carboxylic acid, 6\[(aminophenylacetyl) amino)\]-3,3- dimethyl-7-oxo ampicillin - Ampicin - **Generic vs. Brand Name** - **GENERIC -** company develops drug and give its official name. - are usually cheaper than brand or Trade name drugs - Patient and insurance companies prefer generic drugs-Helps decrease cost of drug - **Brand name-** Drug commercial name which may vary - **Therapeutic Equivalence-** Same chemical composition, FDA conduct studies, Generic drug is interchangeable with brand name drug. - **General Terms** - **Legal Classification** - OTC/ Non-prescription Drugs - Prescription Drugs - Illegal or Recreational Drugs **IMPORTANT!** - Learn Drug by category - Don't learn each drug individually **\*\*\*\* Prototype** - Drug providers commonly prescribed. - Drug administration table **[Lesson 2: Major Areas of Pharmacology]** **Areas of Pharmacology:** - **Pharmacokinetics:** study of the processes of drug ADME (Absorption, Distribution, Metabolism, Excretion) - **Pharmacodynamics:** study of the biochemical and physiological effects of the drugs as well as their MOA (Mechanism of Action) - **Pharmacotherapeutics:** study of how drugs may be used in the treatment of the disease **Pharmacokinetics** - **Absorption:** taken into the body - **Distribution:** moved into various tissues - **Metabolism/ Biotransformation:** changed into a form that can be excreted - **Excretion:** removed from the body **Absorption-** the process by which drug passes from its site of administration into the bloodstream - **Factors affecting drug absorption** - blood flow, pain, stress, food, exercise, nature of absorbing surface, solubility of the drug, pH, drug concentration, dosage form - **Types of absorption** - Passive - Active - Pinocytosis - **Different sites of absorption in the GIT** - mouth or oral cavity - stomach - small intestine\* - **Hepatic first pass/first pass effect\*\*** **Distribution-** the transportation of a drug from its site of absorption to its site of action - **Factors affecting drug absorption\*** - Circulation - Permeability of cell membrane - Plasma protein binding - **Bioavailabity:** percentage of the administered drug dose that reaches the systemic circulation\*\* **Metabolism** - biotransformation or detoxification - a sequence of chemical events that change a drug to a less active form after it enters the body - principal site is the liver - hepatic first pass effect - **Factors affecting drug metabolism\*** - Age - Nutrition - amounts of major body hormones - liver disease **OUTCOME OF METABOLISM:** - increased renal excretion of medication - Inactivation of medications - Increased therapeutic effect - Activation of pro-medications (also called pro-drugs)into active forms - Decreased toxicity when active forms of medications become inactive forms - Increased toxicity when inactive forms of medications become active forms **Excretion-** the primary process by which drugs are eliminated from the body. Drugs can be excreted by the kidneys, intestines, lungs, mammary, sweat and salivary glands - **Factors affecting renal excretion\*** - GFR, tubular secretion rate, urine pH, decreased blood flow to the kidneys, other drugs, blood concentration levels, half-life **Old Age and Drugs** - Altered memory, less acute vision, decreased renal function, less complete and slower absorption from the gastrointestinal tract, increased proportion of fat to lean body mass, decreased liver function, decreased organ sensitivity, altered quality of organ responsiveness. **Pharmacodynamics** - **Mechanism of Action (MOA):** explanation of how a drug produces its effect - **Indication:** intended use(s) of any drug - **Contraindication:** refers to the situation or circumstance when a particular drug should not be given - **Maintenance Dose:** exact amount of a drug that is administered to maintain drug blood level in the therapeutic range - **Loading Dose:** a large initial dose given to achieve immediate drug effect - **Potency:** a measure of the strength of a drug required to produce a specific response - **Receptor Site:** specific location on a cell membrane or within the cell where a drug attaches to produce an effect - **Receptor Theory:** drugs act through receptors by binding to the receptor site to produce or initiate and to block or prevent a response - **Agonists:** drugs that stimulate or produce a response; 2 properties- affinity and efficacy\* - **Antagonist:** drugs that block or do not stimulate a response\* - **Competitive-antagonism:** when both agonist and antagonist drugs are given together, they may compete with each other for the same receptor site - **Partial agonists:** act as agonists and antagonists, with limited affinity to receptor sites. **Onset, Peak & Duration** - **Onset:** the time it takes to reach the minimum effective concentration (MEC) after a drug is administered\* - **Peak:** occurs when the drug reaches its highest blood or plasma concentration - **Duration:** the length of time the drug has a pharmacologic effect **Dose Response and Maximal Efficacy** - **Dose response** is the relationship between the minimal versus the maximal amount of drug dose needed to produce the desired drug response - some patients respond to a lower drug dose, others need a high drug dose to elicit the desired response - all drugs have maximum drug effects (maximal efficacy) **Receptors** - most are protein in structure and are found on cells - drug binding sites are primarily on proteins, glycoproteins, proteolipids, and enzymes - the "ligand binding domain" is the site on the receptor in which drugs bind **Side Effects, Adverse Reactions and Toxic Effects** - **Side Effects:** physiologic effects not related to the drug's desired effect; all drugs have side effects, desirable or not\* - **Adverse Reactions:** more severe than side effects; range of untoward effects of drugs that cause mild to moderate side effects including anaphylaxis; always undesirable - **Toxic Effects or Toxicity:** can be identified by monitoring the plasma (serum) therapeutic range of drug\*\* **Therapeutic Index** - **The relationship between a drug's desired therapeutic effect and its adverse effect** - measures the margin of safety of a drug expressed as the ratio of LD50 to ED50 - **therapeutic ratio = LD50/ED50** - **therapeutic range or window:** range of plasma concentration that produces the desired effect without toxicity **Pharmacotherapeutics\*** - **Acute Therapy:** if the patient is critically ill and requires acute intensive therapy - **Empiric Therapy:** based on practical experience rather than on pure scientific data - **Maintenance Therapy:** for patients with chronic conditions that don't resolve - **Supplemental or Replacement:** to replenish or substitute for missing substances - **Supportive:** does not treat the cause of the disease but maintains other threatened body systems until the patient's condition resolves - **Palliative:** used for end-stage or terminal diseases to make the patient as comfortable as possible **[Lesson 3: Principles in Drug Administration]** **Important Things to Remember!** - Observe the 12 Rights - Practice asepsis - Nurses who administer medications are responsible for their own actions - Be knowledgeable about the medications that you administer - Keep narcotics and barbiturates in locked place - Use medications that are in clearly labelled containers **10 RIGHTS OF GIVING MEDICATION** 1. **RIGHT CLIENT** - Verify clients' identification before each medication administration. - Acceptable identifiers include the client's name, an assigned identification number, telephone number, birthdate, or another person-specific identifier, such as a photo identification card. - Check identification bands for name and identification number. - Check for allergies by asking clients, looking for an allergy bracelet or medal, and reviewing the MAR. - Use bar-code scanners to identify clients. 2. **RIGHT MEDICATION** - Correctly interpret medication prescriptions, verifying completeness and clarity. - Read medication labels and compare them with the MAR three times: before removing the container, when removing the amount of medication from the container, and in the presence of the client before administering the medication. - Leave unit-dose medication in its package until administration. 3. **RIGHT DOSE** - Use a unit-dose system to decrease errors. If not available, calculate the correct medication dose. - Check a drug reference to ensure the dose is within the usual range. - When performing medication calculations or conversions, have another qualified nurse check the calculated dose. - Prepare medication dosages using standard measurement devices 4. **RIGHT TIME** - Administer medication on time to maintain a consistent therapeutic blood level. - It is generally acceptable to administer the medication 30 min before or after the scheduled time. Refer to the drug reference or the facility's policy for exceptions. - Give priority to time-critical medications that must act at specific times (preoperatively) 5. **RIGHT ROUTE** - Select the correct preparation for the route the provider prescribed. - Always use different syringes for enteral and parenteral medication administration. - Know how to administer medication safely and correctly. 6. **RIGHT DOCUMENTATION** - Immediately record the medication, dose, route, time, and any pertinent information, including the client's response to the medication. - Document the medication after administration, not before. - For some medications, in particular to those that alleviate pain, evaluate the client's response and document it later, perhaps after 30 min. 7. **RIGHT EDUCATION** - Inform clients about the medication: its purpose, what to expect, how to take it, and what to report. - To individualize the teaching, determine what the clients already know about the medication, need to know about the medication, and want to know about the medication 8. **RIGHT TO REFUSE** - Respect clients' right to refuse any medication. - Explain the consequences, inform the provider, and document the refusal. 9. **RIGHT ASSESSMENT** - Collect any essential data before and after administering any medication. - For example, measure apical heart rate before giving digoxin 10. **RIGHT EVALUATION** - Follow up with clients to verify therapeutic effects as well as side and adverse effects. **Sources of Drug Information** - **Drug Handbook-** medical reference text commonly used in practice by health professionals - **Physician's Desk Reference (PDR)-** Commercially published compilation of manufacturer's prescribing information (package insert) on prescription drugs, updated annually\* - **Package Inserts-** prescribing information; a document provided along with a prescription medication to provide additional information about a drug. - **Nursing Journals-** a magazine or periodical, especially one published by a nursing specialist or professional body for nurses containing information and contributions relevant to nursing. - **Medical Letter-** a scientific journal that provides independent evaluations of drugs based on novel information - **Monthly Index of Medical Specialties (MIMS)-**contains information about drugs in a certain country; serves as medical advertising medium **Legal Aspects of Drug Administration** **[USA]** - **Food, Drug and Cosmetic Act (1938)** - Empowered a governing body, the Food and Drug Administration (FDA) to monitor and regulate the manufacture and marketing of drugs - FDA's responsibilities include ensuring that all drugs are tested for harmful effects, have labels with accurate information, and enclose with the drug packaging detailed literature that explains adverse effects - **Durham-Humphrey Amendment to the 1938 Act (1952)** - Distinguished drugs that can be sold with or without prescription and those that should be refilled without a new prescription - **Kefauver-Harris Amendment (1962)** - made statements about adverse reactions and contraindications; introduced drug-testing methodologies - tightened controls on drug safety, especially experimental drugs and required that adverse reactions and contraindications must be labelled and included in the literature\* - **Controlled Substances Act (1970)** - categorized controlled substances based on their abuse potential - offered manufacturers incentives to develop drugs for rare disorders that have limited market - designed to remedy the escalating problem of drug abuse - **Provisions** - promotion of drug education and research into the prevention and treatment of drug dependence - strengthening of enforcement authority - establishment of treatment and rehabilitation facilities - designation of schedules or categories for controlled substances according to abuse liability **Schedules\* of Controlled Substances** - **Schedule I-** high potential for abuse and with no currently accepted medical use - **Schedule II-** high potential for abuse with currently accepted medical use; can lead to strong physical and psychological dependence - **Schedule III-** high potential for abuse; requires a new prescription after 6 months or 5 refills; medically accepted drugs but may cause dependence - **Schedule IV-** low potential for abuse compared to the first three; abuse may lead to limited physical or psychological dependence; medically-accepted drugs - **Schedule V-** low potential for abuse; dispensed as any other prescription or without prescription if the law allows; medically-accepted drugs with limited potential for dependence **[Canada]** - **Food and Drug Act (1953)** - States that no drug, food, cosmetic nor medical device can be fraudulently advertised or sold to the public for use - **Narcotic Control Act (1982)** - Similar to US Controlled Substance Act; the act requires prescriptions and strict record keeping for all narcotics **[Philippines]** - **Dangerous Drugs Act (2002) RA 9165; (1972) RA 6425** - states that sale, administration, delivery, distribution and transportation of prohibited drugs are punishable by law\* - **Generics Act (1988) RA 6675** - promotes, requires, and ensures identification of medicines by their generic names\*\* - **Cheaper Medicines Act (2008) RA 9502** - provides for cheaper and quality medicines - **Nursing Law (2002) RA 9173** - focuses on independent and coordinated function of the nurse pertaining to the application and execution of written legal orders of physician concerning treatment and medication **Pregnancy Categories for Drugs** - **Category A:** no risk for fetus; studies have not shown evidence of fetal harm - **Category B:** insufficient data to use in pregnancy; no risk in animal studies; assumed there is little to no risk in pregnant women - **Category C:** benefits of the medication could outweigh the risks; animal studies indicate a risk to fetus; controlled studies on pregnant women are not available - **Category D:** risk to fetus exists but the benefits of the medication could outweigh probable risks; could be used in life-threatening conditions - **Category X:** avoid use in pregnancy or those who may be pregnant; potential risks to the fetus outweigh the potential benefits.