Lecture 13,14 PK-PD Flashcards
What antibiotics are concentration dependent when it comes to MIC?
aminoglycosides, fluoroquinolones, daptomycin, metronidazole (against anaerobes)
What antibiotics are concentration independent when it comes to MIC?
beta-lactams, glycopeptides macrolides, clindamycin, tetracyclines, linezolid
How do beta-lactam antibiotics work regarding MIC?
they are time-dependent,
substantially increasing drug conc have minimal effect on overall rate and extent of bacterial killing,
its more important to maintain a free drug conc above MIC ⇒ target is to have fT>MIC > 40% for bacteriostasis and > 75% for bactericidal
What is fAUC/MIC, and what antibiotics does it apply to?
measures of drug exposure over a period (usually 24 hours) in relation to MIC of the organism correlate with efficacy for most antibiotic classes,
allows flexibility in dosing regimens,, incorporates both time (vancomycin) and conc (fluoroquinolones) dependence in determining rate and extent of killing
What is the target fAUC/MIC for fluoroquinolones?
its > 125 for gram - organisms and > 30 for gram +
What is the target fAUC/MIC for vancomycin?
target is > 400, surrogate: trough 10-20 mg/L
What is Cmax/MIC?, and what antibiotics does it apply to (and the target for this class)?
aminoglycosides are most exemplar class where bacterial kill is maximized by attaining higher maximal conc,
maintaining conc above the MIC for extended period of interval is unnecessary and may increase risk of AEs,
the target is fCmax/MIC > 8-10
What is meant by the post-antibiotic effect (PAE)?
continued suppression of bacterial growth from previous exposure to antibacterials once levels are below MIC,
generally all antibacterials show this,
agents that alter nucleic acid or protein synthesis tend to have longer ones compared to cell wall agents,
allows for longer dosing intervals between doses without compromising efficacy
