Pharmacology

Question 1

Mechanisms of resistance

Answer 1

malabsorption, pumping out, inactivation, ineffective, increased production of target molecules, develop alter metabolic pathways

Question 2

how does resistance arise

Answer 2

temporarily, chomosomally, extrachromosomally (addition of plasmid, multiple gene combination)

Question 3

how to minimize emergence of resistence

Answer 3

only use when clearly indicated, use as narrow spectrum as possible, use effective dose, consider phenotype/genotype of patient, ensure adequate duration, use older drugs when possible and combination drugs

Question 4

superinfections

Answer 4

alter the normal flora by removing some, others overgrow in its place

Question 5

how to distinguish superinfections from side-effects

Answer 5

if they have symptoms immediately after drug infection, it’s a side effect. but if it takes a couple days to set in, it’s a superinfection

Question 6

three major classes of GI superinfections

Answer 6

candidiasis, staph enterocolitis, and psudomembranous colitis

Question 7

candidiasis superinfection

Answer 7

fungal overgrowth, most common, continue antibiotic but add antifungal

Question 8

staphylococcal enterocolitis superinfection

Answer 8

life-threatening superinfection, altered bacterial populations allow the overgrowth of staph, discontinue antibacterial and administer anti-staph penicillin or vancomycin

Question 9

pseudomembranous colitis superinfection

Answer 9

life-threatening C. diff overgrowth, discontinue antibacterial and administer metronidazole or vancomycin

Question 10

toxicity

Answer 10

dose-related, tissues that experience higher concentrations are more susceptible

Question 11

hypersensitivity

Answer 11

drug allergies, immune-mediated, not related to therapeutic dose range

Question 12

idiosyncratic responses

Answer 12

linked to drugs, but low frequency and not really related to dose, more genetically determined

Question 13

how to administer the appropriate chemotherapy

Answer 13

based on culture AND susceptibility testing, monitor for therapeutic and toxic effects

Question 14

purpose of combination therapy

Answer 14

enhanced therapeutic effect (synergism), allow use of lower doses to minimize toxicity, can combine 2 statics and they’ll become cidal, delay resistance, treat mixed infections, and initiate therapy in life-threatening situations before pathogen is known

Question 15

who is a candidate for chemoprophylaxis

Answer 15

healthy individuals following known exposure, individuals with known dormant pathogen to minimize episodes, post-surgical patients and patients susceptible to endocarditis

Question 16

drug selection in 4 steps

Answer 16

1. can the drug affect the pathogen, based on susceptibilities?
2. are the pharmacokinetics appropriate (renal failure, drug-drug interactions, etc.)
3. is the drug appropriate for the patient (age, reproductive status, allergies, etc.)
4. is this the ideal drug? (oral, cytocidal, cost, stage of the drug development?)