NUR 210 Pharmacology Principles Final Exam 2025

NUR 210 Pharmacology Principles Final Exam 2025 Drug response - -the intensity of the drug response is directly related to the concentration of the drug at the site of action Goal is to: - Maximize the beneficial effects- concentration high enough for desired response - Minimize harm- avoid to high a concentration Three phases of drug action - - 1. Pharmaceutic phase (dissolution) 2. Pharmacokinetic phase (drug moving through the body) 3. Pharmacodynamic phase (what the drug does to the body) 1. Pharmaceutic phase – -the drug goes into solution - Dissolution: the process by which a drug goes into solution and becomes available for absorption - must be dissolved before it can be absorbed - most absorption takes place in the small intestine 2. Pharmacokinetic phase: four processes - -"what the BODY does to the drug" - absorption - distribution - metabolism/ biotransformation - exertion Pharmacokinetic phase: Absorption - -(small intestine) the movement of a drug from its site of administration into the blood Pharmacokinetic phase: Distribution - -drug moves from blood -- cell membrane Pharmacokinetic phase: Metabolism/biotransformation - -lipid soluble metabolite (liver) -- a water soluble metabolite Pharmacokinetic phase: Excretion - -water soluble metabolite (kidneys) Liver - -breaks down the drug Kidneys - -excretes the drug NUR 210 NUR 210 Pharmacokinetic phase movement process - -orally -- stomach -- SI -- bloodstream -- site of action -- liver (broken down) -- kidneys (excreted) IV -- bloodstream -- cite of action -- liver -- kidneys Drugs crossing the cell membranes phospholipid cell layer - --drugs must be LIPID SOLUBLE in order to pass through the membrane - WATER SOLUBLE drugs penetrate the cell membrane through channels and pores Absorption 1. Direct penetration of the membranes 2. Channels and pores 3. Transport systems - -the movement of a drug from its site of administration to the blood How do drugs cross membranes? 1. Direct penetration of the membranes - - - use by MOST drugs - most drugs to large to pass thru channels and pores - most drugs lack transport systems - drugs must be lipid soluble to be able to penetrate cellular membranes = lipophilic drugs 2. Channels and pores - -only very small ions such as potassium and sodium can pass through cell membranes 3. Transport systems - -- are carriers that can move drugs from one side of the membrane to the other - are selective Movement of drugs across membranes - - -drugs must cross membranes (pass through cells) to enter the blood from their site of administration - drugs must then leave the blood (vascular systems) to get to their SITE OF ACTION - drugs must then cross membranes again to be metabolized and excreted Pharmacokinetic phase: Absorption - -process that occurs between the time a drug enters the body and the time it enters the bloodstream to be circulated - Rate of absorption - depends on the formulation of drug (tablet, liquid, etc.) NUR 210 NUR 210 - Amount of absorption - how effective drug will be absorbed Major determinants of rate of absorption: - blood flow - higher blood flow, the faster the drug is absorbed - lipid solubility - higher lipid soluble drugs faster than drugs whose lipid solubility is low - ph - acidity of the stomach can break down the drug What is the first-pass effect? - -affects amount of drug absorbed - the metabolism of a drug by the liver BEFORE it reaches systemic circulation - is the % of the drug that is broken down in the liver - "bioavailability" : the fraction of administered drug that actually reaches systemic circulation - IV bioavaiability= 100% - oral bioavailability will vary Three Routes of Absorption - - 1. Enteral 2.Parenteral 3. Topical Enteral route of absorption - -Defined by the way of GI tract (oral/gastric mucosa, small intestine, rectum) - any drug given via GI tract - EC (enteric coated): intended to break down in the small intestine NOT the stomach - must undergo the "first pass effect" - PO -- portal circulation -- must undergo the first pass effect - SL, buccal, rectal -- absorbed into highly vascular tissue under tongue or in the rectum (by passes liver so little to NO first pass effect) Enteral routes of absorption - - EC PO SL, buccal, rectal Parenteral route of absorption - -SQ, IM, IV, intrathecal (into special cord), epidural (into spine) IV fastest route (NO barriers to absorption- absorption instant, complete, and irreversible) - most common route Topical (transdermal) route of absorption - -application of meds to body surfaces - skin, eyes, ears, nose, lungs Important - -all meds given PO have some first pass effect NUR 210 NUR 210 Routes of administration Affected by: - -- dosage form (ie, liquid vs tablet)- liquids absorbed faster - route (ie, IV vs PO) - IV fastest action - GI function: Solubility and stability of the drug Gastric emptying time Coatings on the drug itself Ph Food Oral administration preparations - -Tablets: 1. Chemical equivalent 2. Bioavailability Enteric-coated -dissolves in intestine instead of stomach -absorption is variable Capsules - filled with granules or liquid (liquid absorbed faster) Sustained Release (SR) - drug released slowly by tiny spheres that contain the actual drug. Can take fewer doses. - Also CR (controlled release) and ER (extended release) Pharmacokinetic phase: Distribution - -- the movement of the drug through the body - process by which drug molecules LEAVE the blood stream