NCM 106 (Pharmacology) Week 2 Notes (Notre Dame University)

NOTRE DAME UNIVERSITY COLLEGE OF HEALTH SCIENCES NCM 106 (PHARMACOLOGY) st 1 Semester AY 2023-2024 FIRST TRINAL CONCEPT  WEEK 2 D. Pharmacokinetics E. Factors influencing responses to drugs F. Drugs Legislation Controlled Substances, Generic Drugs, Orphan Drugs, and Over-the...

NOTRE DAME UNIVERSITY COLLEGE OF HEALTH SCIENCES NCM 106 (PHARMACOLOGY) st 1 Semester AY 2023-2024 FIRST TRINAL CONCEPT  WEEK 2 D. Pharmacokinetics E. Factors influencing responses to drugs F. Drugs Legislation Controlled Substances, Generic Drugs, Orphan Drugs, and Over-the-Counter Drugs. OBJECTIVES : 1.Determine the processes involved as drugs are absorbed & distributed inside the body 2.Discuss pharmacokinetics 3.Identify the factors influencing responses to drugs 4.Determine ethico-legal considerations when providing safe, quality & professional nursing care.  is the study of drug movement throughout the body. is derived from two Greek words: pharmakon (drug or poison) and kinesis (motion). PHARMACOKINETICS Pharmacokinetic Considerations A. Onset of drug action B. Drug half-life C. Timing of the peak effect D. Duration of drug effects E. Some drugs produce effects in minute but others may take hours or days F. Metabolism (biotransformation) of drug G. Site of excretion  Critical Concentration Loading Dose Dynamic equilibrium 1.LIBERATION ✓ also known as the PHARMACEUTIC EFFECT relating to the dosage form being used. ✓ the process of converting a drug into a soluble form can be partially controlled by the pharmaceutical dosage form used drug routes drug forms  2.ABSORPTION Drug absorption covers the progress of a drug from the time it’s administered, through the time it passes to the tissues, until it becomes available for use by the body. Drug absorption is influenced by the route of administration ORAL ROUTE INTRAVENOUS INTRAMUSCULAR Absorption Process How drugs are absorbed ? 1. Passive transport 2. Active transport 3. Filtration/ Pinocytosis drug moves from an area of higher concentration to one of lower concentration (diffusion). requires no cellular energy requires cellular energy Pinocytosis is a unique form of active transport that occurs when a cell engulfs a drug particle. Routes of Administration: Drug absorption is influenced by the route of administration. Generally, drugs absorbed by oral route are absorbed more slowly than those given parenterally. Drugs that are injected intravenously (IV) reach their full strength at the time of injection, avoiding initial breakdown. Drugs that are injected intramuscularly (IM) are absorbed directly into the capillaries in the muscle and sent into circulation. Factors Affecting Drug Absorption physical & chemical properties of the drug physiologic & anatomic factors at the absorption site. Rate of Dissolution Before a drug can be absorbed, it must first dissolve. Surface Area A major determinants of the rate of absorption. Orally administered drugs are usually absorbed from the small intestine rather than from the stomach. Blood Flow Drugs are absorbed most rapidly from sites where blood flow is high. The greater the concentration gradient, the more rapid absorption will be. Lipid Solubility highly lipid-soluble drugs are absorbed more rapidly than drugs whose lipid solubility is low. lipid soluble drugs can readily cross the membranes that separate them from the blood, whereas drugs of low lipid solubility cannot. pH Partitioning influences drug absorption. Pharmacokinetic Considerations A.Onset of drug action B.Drug half-life C.Timing of the peak effect D.Duration of drug effects E.Some drugs produce effects in minute but others may take hours or days F.Metabolism (biotransformation) of drug G.Site of excretion 3.DISTRIBUTION A process by which the drug becomes available to body fluids & body tissues. Movements of drug from the blood to the interstitial space of tissues & from there into cells. Distribution ❖Transportation of drug molecules within the body ❖Drug needs to be carried to the site of the action ❖Need blood to circulate the drug to the Heart, liver, kidneys Distribution… -involves movement of a drug to the body's tissues ✓ Protein Binding ✓ Blood-Brain Barrier ✓ Placenta & Breastmilk Protein binding of drugs Drug movement across the blood-brain barrier Placental drug transfer  4.METABOLISM (BIOTRANSFORM ATION) > The chemical alteration of drug structure. > Most drug metabolism takes place in the liver. METABOLISM (BIOTRANSFORMATION)… ❖Method by which the drugs are inactivated or biotransformed by the body ❖Detoxification occurs in the liver ❖Most drugs metabolized by cytochrome P450 (CYP) making them into less active chemicals  first pass The effect (also known as first- pass metabolism or presystemic metabolism ) Is a phenomenon of drug metabolism whereby the concentration of a drug, specifically when administered orally is greatly reduced before it reaches the systemic circulation. Drug Metabolism six possible consequences of therapeutic significance: Accelerated renal excretion of drugs Drug inactivation Increased therapeutic action Activation of “prodrugs” Increased toxicity Decreased toxicity  4. EXCRETION Is the removal of a drug from the body. Drugs & their metabolites can exit the body in urine, bile, sweat, saliva, breast milk, & expired air. The most important organ for drug excretion is the kidney.  Half- life the length of time required for the concentration of a particular substance (typically a drug) to decrease to half of its starting dose in the body.  Half-Life Time required for the body to eliminate 50% of the drug Plan the frequency of dosing Drugs with short half-life Drugs with long half-life *Difficulty in drug excretion: Increases half-life and risk of toxicity Half Life Importance: 1. Gives a gross idea about the Pharmacokinetics & Pharmacodynamics of a drug. 2. Gives idea about the duration of action of a drug. 3.It can guide the dosage schedules. > Low half life ---→ frequent administration > High half life -→ should be given once or twice a day. A short half-life is considered to be 4-8 hours, and a long one is 24 hours or longer. Renal Drug Excretion The kidneys account for the majority of drug excretion. When the kidneys are healthy, they serve to limit the duration of action of many drugs. Nonrenal Routes of Drug Excretion > Breast Milk  Factors Influencing Responses to Drugs WEIGHT GENDER ENVIRONMENTAL CONDITIONS Immunologic Factors TOLERANCE Ethico-legal considerations when providing safe, quality and professional nursing care. Nurse Practice Acts nurses cannot prescribe or administer drugs without a health care provider’s order. Ethical Values universal rules of conduct that provide a practical basis for identifying what kinds of actions, intentions, and motives are valued. Ethics are moral principles that govern how the person or a group will behave or conduct themselves. Provisions of the American Nurses Association Code of Ethics Provision 1. The nurse practices with compassion and respect for the inherent dignity, worth, and unique attributes of every person. Provision 2. The nurse’s primary commitment is to the patient, whether an individual, family, group, community, or population. Provision 3. The nurse promotes, advocates for, and protects the rights, health, and safety of the patient. Provision 4. The nurse has authority, accountability, and responsibility for nursing practice; makes decisions; and takes action consistent with the obligation to provide optimal patient care. Provision 5. The nurse owes the same duties to self as to others, including the responsibility to promote health and safety, preserve wholeness of character and integrity, maintain competence, and continue personal and professional growth. Provision 6. The nurse, through individual and collective effort, establishes, maintains, and improves the ethical environment of the work setting and conditions of employment that are conducive to safe, quality health care. Provision 7. The nurse, in all roles and settings, advances the profession through research and scholarly inquiry, professional standards development, and the generation of both nursing and health policy. Provision 8. The nurse collaborates with other health professionals and the public to protect human rights, promote health diplomacy, and reduce health disparities. Provision 9. The profession of nursing, collectively through its professional organization, must articulate nursing values, maintain the integrity of the profession, and integrate principles of social justice into nursing and health policy. Clinical Significance Autonomy Beneficence Justice  Non- maleficence 76  References: Basic & Clinical Pharmacology 14th edition,2018 Edited by Bertram G. Katzung, MD, PhD Lehne’s PHARMACOLOGY for NURSING CARE 10th EDITION,2019 Jacqueline Rosenjack Burchum, Pharmacology A Patient-Centered Nursing Process Approach 9th EDITION Linda E. McCuistion Pharmacology Classifications of Drugs (Drug Classifications) (sanalake.com)