Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
11 Cards in this Set
- Front
- Back
|
1.What is the therapeutic index concept a measure of?
2.What is the equation |
1. measure of selective toxicity
2. maximum tolerated dose(host)/minimal effective dose(microbe) |
|
|
1.What is MIC?
2.At what MIC is an organism considered susceptible to a drug? 3.What is 'Breakpoint MIC'? 4. What is MBC? |
1.Minimum inhibitory concentration-lowest concentration that prevents visible growth after 24 hours incubation
2. organism is considered susceptible when the MIC is <25% of the readily obtained Cmax of the antimicrobial agent 3.quantitative upper limit of susceptibility (takes into account clinical pharmacology of a drug as well as susceptibility 4. minimum bactiericidal concentration=smallest concentration of a drug that will kill an organism |
|
|
What are Post-antibiotic effects?
|
-relationship of MIC and PDC (plasma drug concentration)
|
|
|
Define
1.Bactericidal 2.Bacteriostatic |
1.MIC and MBC are close together; utilizes host immune system
2. large dilution difference between MIC and MBC |
|
|
Why do gram negative bacteria have such a high MIC?
|
difference in cell wall morphology (extra lipid bilayer) -this may also lead to resistance to some drugs
|
|
|
What is meant by broad spectrum?
|
kills 3 or 4 of following groups:
-gram+ve aerobes -gram+ve anaerobes -gram-ve aerobes -gram-ve anaerobes (narrow spectrum=1 or 2 of these groups) |
|
|
What are time-dependent antibiotics? Examples?
|
1.percentage of time during the dose interval where the serum concentration of an antibiotic remains above the MIC
-efficacy improved by keeping the percent time above MIC above 50% in most patients and close to 100% in immunosuppressed patients -concentration CORRELATES with its clinical efficacy (efficacy dependent on total time above MIC/24 hour period) 2.macrolides, lincosamides, slower killing antimicobials such as beta lactams. |
|
|
What are dose-dependent antibiotics? Examples?
|
1. peak serum to MIC ratio/inhibitory quotient
-log area under serum concentration curve -correlates with clinical efficacy of quick killing antimicrobials with long post antibiotic effects (aminoglycosides, fluoroquinolones) -measure of total drug exposure -peak serum concentration of 4-8 times the MIC *efficacy of dose-dependent drugs depends on the total amount above MIC/24 hour period* |
|
|
What is the post-antibiotic effect? What is PALE?
|
-persistance of the antimicrobial effect after brief exposure to (or the lack of detectable concentration of) an antimicrobial
2. Post-Antibiotic Leukocyte Enhancement |
|
|
What are the 6 principle mechanisms of resistance?
|
1. Mutation=decreased permeability of drug in cytoplasmic membrane
2. increased production of drug destroying enzyme 3. up regulation of target enzyme 4. target enzyme replaced by one with less affinity for the drug 5. increased synthesis of a target metabolite 6. active extrusion of the drug via MDR P-glycoprotein pump |
|
|
Beta Lactams:
1.MOA 2. Examples (types) 3. Microbial Resistance mechanisms |
1.target cell wall (peptidoglycan); less effective against gram negative (increased peptidoglycan + enzymes can break down antibiotic); disrupts peptide cross-links (osmotic lysis of bacteria); inhibit transpeptidase enzyme
2.-Penicillins -cephalosporins -monobactams -carbapenems (all have beta lactam ring-integrity crucial for antibacterial effect) 3. resistance dependent on: production of beta lactamases(enzymes that inactivate the drug by hydrolizing beta lactam ring) |
