NURS 682 Pharmacology Midterm Elaborated Exam 2025

Pharmacokinetics - -what the body does to the drug (absorption, distribution, metabolism, excretion) Pharmacodynamics - -what the drug does to the body; mechanism of action Pharmacodynamics-- study determining the effect of a specific medication dose in treating a disease Bioavailability - --Percent of dose enter systemic circulation after PO administration *Fraction of the administered drug that reaches systemic circulation* Lower bioavailability - -LESS drug there is in circulation and in the tissue, higher first pass effect ex. Simvastatin Higher bioavailability - -the more of the drug that reaches systemic circulation, Lower first pass effect ex. Atorvastatin Tmax - -Time to maximum drug level observed Cmax - -maximum or peak concentration of drug observed after administration Volume of distribution - -Vd = (amount of drug in the body) / (plasma drug concentration) -distribution of a medication between plasma and the rest of the body; the volume in which the amount of drug would need to be uniformly distributed to produce the observed blood concentration ex. Vancomycin in serum testing for trough levels Volume of distribution: age related changes - --Healthy adults 20-30 vs. 60-80 -Older adults get more dehydrated -Medications that are lipophilic will stay longer in the older adult and older adults get -Liver shrinks with age and albumin is synthesized in the liver. There is freer drug available in highly protein bound drugs—-Decrease in serum albumin NURS 682 -Most drugs are biotransformed in the liver, with older adults there is slower transformation and longer half lives Factors that influence volume of distribution - -Aging -less free water, more body fat -lower average serum albumin Hydration Status Compartment and volume First Pass Effect (pre-systemic elimination) - -Biostranformation and/or excretion of oral drug by hepatic mechanisms -occurs prior to entering GI tract Drugs absorbed from the GI tract Extensive hepatic citon Ex. IV vs oral dosages Agonists - -Works primarily by stimulating the activity of a receptor site binds to a receptor, causes an effect similar to endogenous compound Antagonist - -Clinical action= occupying a receptor site and inhibiting its endogenous activity Narrow therapeutic Index - -small differences in drug dose or blood concentration can be fatal Any pharmaceutical which has 2-fold difference between the minimum toxic concentration and minimum effective concentration in blood Wide therapeutic index - -Greater distance between effective dose and toxic dose Ex. Fluoxetine does NOT need drug monitoring Pharmacogenetics: PK genetic influences - -Drug absorption, distribution, metabolism, excretion Influence dose requirements and/or adverse effects Pharmacogenetics: PD genetic influences - -Drug targets: Receptors, transporters, intracellular signaling pathways, enzymes and metabolic pathways NURS 682 NURS 682 NURS 682 Influence drug efficacy Drugs with QT prolongation - -Ventricular repolarization prolongation Ectopic beats with long pause follow by baseline rhythm beat with marked prolonged QT interval Underlying risk factors + Adding medications with QT prolonging effects Known: Amiodarone, Haldol Known risk of QT prolongaiton - -OLDER AGE Summary of Age-Related Changes - -Older adults have.... -less % body weight as water -less lean muscle mass -higher % weight as fat -LOWER SERIUM ALBUMIN** -lower relative kidney weight -less relative hepatic blood flow Beer's Criteria - -Unconditionally inappropriate meds & Generally best avoided regardless of circumstances Usually alternative available Conditioned upon disease state & dose Likely only to be inappropriate in specific context Age-related changes that impact drug effect / general pharm rules for the elder - -Beer's Criteria **Avoid medications with systemic anticholinergic ridged effect due to risk of confusion, urinary retention, constipation, visual disturbance and hypotension DO NOT continue unwise practices that are seen in daily clinical settings Have multiple choices in a drug class, choose a product with a shorter half life While PD (pharmakodynamics) doesn't change with gaining some age-related changes will result in less drug effect **In the elder: loss of B-2 receptor sites Less bronchodilator effect with -terol meds BUN - -blood urea nitrogen NURS 682 NURS 682 Evaluation of the amount of nitrogen in the blood in urea form Urea= metabolism by-product of proteins by liver, removed from the blood by kidneys Creatinine - -Breakdown product of muscle creatinine phosphate and is usually produced at fairly constant rate by the body (depending on muscles mass) **Creatinine is greater with higher muscle mass and lower with low muscle mass** BUN: Creatinine (BUN:Cr) - -Usually less than 20:1 in presence of appropriate hydration -Reduced in order hydration Often elevated in renal disease -In absence of renal disease, can be transiently elevated in dehydration, ingestion of extreme amounts of protein, upper/lower GI bleed Cockcroft-Gault equation - -Used to calculate GFR to take into account differences b/t male and female USE IBW Cr Cl in men (140-age) x wt in kg/(72 x sCr) Cr Cl in women (140-age) x wt in kg/(72 x sCr) x 0.85 Antibiotic use in pregnancy: Category B - -Category B= best Animal studies have not demonstrated fetal risk but no controlled study in humans OR Animal studies have shown adverse effect but not demonstrated in human study Beta-lactation abx -Penicillins -Cephalosporins Macrolides -Azithromycin, erythromycin but NOT clarithromycin Antibiotic Use in pregnancy: Category C - -No controlled study in humans available Studies in animals have revealed. Adverse effects on the fetus -Embryocidal -Teratogenic -Other 2/3rd of all medications NURS 682 Select abx Clarithromycin (C=C) Fluoroquinolones (cipro = C) -floxacin suffix (levofloxacin)*** Antibiotic use in Pregnancy: Category D - -D= DNAGER Positive evidence of human fetal risk Benefit from use in pregnancy might be acceptable despite the risk Is the condition potentially life-threatening disease vs life-altering? Tetracyclines Doxycycline = D due to teeth staining Priority vaccines during EACH pregnancy - -Inactivated influenza Tdap dose durign each pregnancy irrespective of prior Tdap history Empiric Therapy - -The decision-making processes where the clinical chooses the agent based on patient characteristics and the site of infection Empiric Therapy: Bacteriostatic - -inhibits growth or reproduction of an organism Macrolides - -(-mycin) Azithromycin (Zithromax) Clarithromycin (Biaxin) Erythromycin Macrolides MOA - -Inhibition of bacterial protein synthesis bacteriostatic Macrolides work against... - -variety of gram-positive organisms (S. pneumoniae) and some gram-negative (H. influenzae) and **atypical pathogens (M. pneumoniae, C. pneumoniae)** Play a large role in treatment of respiratory infections Beta Lactams - -(-cillin AND cef- or ceph-) All with a beta-lactam ring Penicillin (penicillin, amoxicillin, ampicillin) Cephalosporins (cefpodoxime, cefuroxime) NURS 682 NURS 682 NURS 682 Beta Lactam MOA - -Disrupt synthesis of peptidoglycan layer of bacterial cell walls Cell wall synthesis inhibitor, organism dies because it can't reproduce Bactericidal Cephalosporins 1st generation - -Cephalexin, others Gram-positive coverage (MSSA), highest risk of cross-reaction in penicillin allergy Cephalosporins 2nd generation - -Cefuroxime, cefprozil, others Gram-positive coverage similar to 1st generation, enhanced Gram-negative coverage (H. influenzae, M. catarrhalis Cephalosporins 3rd generation - -Cefdinir, cefixime, ceftriaxone Varying reliability for Gram-positive coverage, reliable gram-negative activity Cephalosporins 4th generation - -Cefempime, injectable only Gram-positive, gram-negative (Pseudomonas coverage) Cephalosporins MOA - -inhibit cell wall synthesis Clinical and bacteriologic success correlates with the length of time bacteria are exposed to agent at concentration that exceeds MIC Often dosed multiple times a day Fluoroquinolones 2nd generation - -Ciprofloxacin Largely gram-negative coverage (E.coli, others) E.coli is most common cause of UTI across lifespan Less reliability acting again Gram-positive pathogens (S. pneumoniae, S. aureus) Fluoroquinolones 3rd generation - -Levofloxacin (Levaquin), Moxifloxacin (Avelox), Gemifloxacin (Factive) Activity against select gram-positive organisms (S. pneumoniae including drug resistant strains). Gram-negative (H. influenze, others), and atypical pathogens (M. pneumoniae, C. pneumoniae) Usually used for respiratory infections Fluoroquinolones MOA - -Inhibit bacterial DNA gyrase or topoisomerase IV enzyme, ends with DNA inhibiting DNA replication and transcription (so organism cannot reproduce) Consider lifespan of organism becaus