NURS 615 Study Guide Exam I Questions and Answers 100% Solved

NURS 615 Study Guide Exam I Questions and Answers 100% Solved What factors are associated with clinical judgment when prescribing medications? Thorough assessment of patient and patient environment Medical and Nursing Diagnoses Review of potential alternative therapies Specific knowledge about drug chosen Information about disease you are trying to treat This is patient centered care should be most effective, least invasive and least expensive What are the criteria for choosing an effective drug? Nationally recognized guidelines should be used to choose most effective drug treatment JNC7 for hypertension Recommendations for SPE prophylaxis for endocarditis put out by American Cardiac Physicians and AHA How does hypoalbuminemia affect the process of prescribing? Many drugs that carry an electric charge bind with albumin in the blood The distribution of drug to the targeted tissues may be affected if hypoalbuminemia is present What is the drug's half-life? The amount of time for an administered to be half-way cleared from the body Takes 4-5x half life for drug serum to reach steady state after regular dosing is started, stopped, or the dose is changed Digoxin half life 24-36 hours change in dose will take a week for full effect Drugs with long half life like amiodarone 58day half life are usually started with a loading dose to achieve steady state more quickly. Must use half life to determine the length of time required between dosage administrations. What is meant by the onset of action, peak of action, duration of action of medications? Onset: Time between administration and minimum concentration of a drug to produce an effect. First sign of drugs therapeutic effect. Peak: Time between drug administration and maximum concentration of blood in the blood stream Duration: Time between onset of action and the metabolism of drug below minimum needed for effect Explain first pass metabolism. Also called pre-systemic metabolism. Concentration of drug is greatly reduced before systemic circulation Fraction of drug lost in absorption Occurs in liver and gut wall Significant first pass effect drugs: morphine, propanolol, diazepam, demoral, lidocaine, midazolam After a drug is swallowed absorbed by digestive system to the hepatic portal system, then carried through to portal vein to liver then sent to the rest of the body Liver reduces bioavailability Sublingual administration bypasses the first pass effect. Faster than oral and rectal admin What is a steady state? Intake of drug = to elimination Therapeutic level 4 to 5 times half life must occur before steady state is achieved What factors affect the drug's absorption? Introduced via administration (oral, topical, transdermal) in its dosage form Absorption more straight forward in IV, enteral, IM and bioavailability is greater near 100% IV administration does not involve absorption and bioavailability is 100% Fastest route of absorption is INHALATION (not IV) GI tract lined with epithelial cell must permeate these to get to circulatory system. Cell membrane (lipid bilayer) that may inhibit SEMIPERMIABLE. Only permeable to small uncharged solutes. Ionic molecules are charged. Solubility=charged species Permeability=neutral species Henderson Hasselback equation offers a way to determine the proportion of a substance that is ionized in the given pH. In the stomach drugs with weak acids such as aspirin will be present in the non-ionic form and weak bases will be in ionic form. Weak acids have higher absorption in highly acidic stomach. Basic environment in intestines, reverse occurs with caffeine Identify drug metabolism and the role of the isoenzymes of the P450 system. CYPs are the major enzyme involved in drug metabolism account for 75% of total metabolism Most drugs deactivated are directly affected or facilitated by CYP excretion from the body Many substances bioactivated by CYPs to form active compounds Many drugs increase or decrease the activity of various isoactive enzymes by inducing biosynthesis of the isozyme (enzyme induction) or by directly inhibiting the activity of CYP (enzyme inhibition) MAJOR SOURCE OF ADVERSE DRUG REACTIONS changes in CYP activity affect metabolism and clearance of various drugs Interactions between two meds can lead to toxicity prescribers may need to adjust dosages or choose drugs that do not interact IMPORTANT IN DRUGS w/ SMALL THERAPEUTIC WINDOWS Example: Antiepiletic drugs & Amiodarone, Grapefruit juice & medications leading to increase bioavailability and overdose What is the efficacy of the drug? Maximum response achievable from a drug Intrinsic activity Effectiveness--ability to produce beneficial effect On the drug concentration curve what is the first sign of a therapeutic effect? The onset of action What is the purpose of a peak and trough level? To determine if drug is in therapeutic range refers to dosage range or serum concentration. Some patients require more or less than this range. Some may experience toxicity within this range Describe the purpose of the blood brain barrier and the fetal placental barrier. BBB: Highly selective permeable membrane that protects the CNS connected by tight junctions brain and ethelial cells Allows the passage of water, some gases, lipid soluble fluids with passive diffusion Glucose and amino acids are allowed to cross FPB: Impedes certain chemicals most fat soluble chemicals can cross More water soluble drugs and higher molecular weight CANNOT cross. If drug binds to large molecule such as albumin it will not cross How will renal insufficiency affect drug elimination? Kidney primary organ of excretion Rate depends on renal blood flow GFR (glomerular filtration rate) renal function tested by creatinine According to the WHO, what is the first step in the prescribing process? Define patient's problem to determine a clear indication for treatment Consider other medications, allergies, pregnancy, comorbidities Summary of diagnostic part of consultation SECOND STEP: Therapeutic objective; includes monitoring therapeutic treatment THIRD: Choose drug or step needed (a) selection of professional personal drug of first choice (b) confirmation of suitability for patient in question Includes checking for contraindications FOURTH: Making a choice and writing Rx starting treatment FIFTH: Giving patient instructions and warning about treatment SIXTH: Monitoring Effective Treatment (continue, adjust, stop treatment?) What does the FDA have the authority to approve? Protecting and promoting public health through the regulation of Food Safety Tobacco products Rx and OTC drugs/medications Vaccines Biopharmacueticals Blood transfusions cosmetics electromagnetic imaging devices animal foods/feeds veterinary products FDA collects medications and monitors the safety of drugs using post marketing surveillance by the med watch programs Determines the official labeling for all Rx and OTC medications NO REGULATION OVER HERBAL SUPPLEMENTS What is off label prescribing? Off label use is the use of drugs for unapproved indications, age groups, dose, route of administration Both Rx and OTC meds can be used in off label ways Legal unless violation of ethics guidelines for safety regulations Can entail health risk and legal liability Cytotec being used for labor, but on label use for peptic ulcer disease What factors place an infant and child at risk when prescribing medications? Lack safety and efficacy studies in the infant and pediatric populations. Adverse drug reactions are most common in this age group. Children and infants have immature livers and kidneys which place this population at an increased risk for developing adverse reactions. Metabolism and mechanism of action studies performed do not necessarily apply to the infant and pediatric population. What adverse drug reactions (ADRs) are the elderly at risk of developing? Predictable underlying concerns in patients over 65 include taking more medications and taking them more often than younger patients. Most commonly caused by unintentional overdosing. Patients over the age of 65 required hospitalization 7 times more than patients under the age of 65. Physiologic changes increase risk of harm metabolized by the liver and kidneys. Decreased metabolism and clearance cause an elevated drug concentration and risk of drug accumulation and toxicity. Hepatic blood flow decreases by nearly one half in 40% of older adults and some degree of chronic kidney disease is present in one half of older adults. Median renal blood flow decreases by one half by age 80 Individual rate of decline varies and 1/3 of older adults maintain normal renal function Heart failure affects more than 40% of those over 80 further influencing the decline of the kidneys and liver. Aging decreases first pass in the liver and medications require smaller doses (warfarin, benzos, and opiates). Distribution of drugs to body compartments is changed because of the decrease in the ratio of lean body weight and body fat. Levels of serum proteins which binds to many drugs decrease in older adults because of malnutrition and dietary changes that are common for both intentional and unintentional reasons. Substance abuse such as alcohol which is common in the elderly also increases risk of ADRs. What are the ADRS related to special populations? Adverse drug reactions are more likely to occur in patients with renal impairments, children/elderly/females, and patients taking multiple medications. Children and elderly are at the highest risk. Which medications interact with St. John's Wort? St. John's Wort interacts with MAOIs, tricyclic antidepressants, SSRIs, OTC cold and flu medications, narcotics, and sympathomimetic drugs (epinephrine, norepinephrine, dopamine). How does doxazosin work? What is the action and effect of beta blockers? What are the adverse effects of beta blockers? What effect will result with rapid withdrawal of a beta blocker? What patient teaching should be provided when prescribing clonidine or any centrally acting adrenergic blocker? What are the adverse effects of a beta 1 selective blocker? What effect is produced with cholinergic blockers?