Dr. Cluck Anti-Infective PK Flashcards
What are antibiotics divided into based on PK/PD parameters?
-Time-dependent killing
-concentration-dependent killing
What is the Post antibiotic effect (PAE)
-The drug continues to affect organisms’ growth after concentration has fallen below MIC
(Antibiotics are usually not picked based on PAE)
What is the MIC?
-Minimum inhibitory concentration
-the lowest concentration of antibiotics needed to stop visible bacterial growth under standard conditions
-each antibiotic has its own MIC
What is the clinical approach to using Time-dependent antibiotics?
They are dosed in a way to keep the concentration above the MIC for 40-50% of the dosing interval
-ß-lactams, glycopeptides, macrolides, clindamycin, linezolid
What is the classic Time-dependent-Killer (Time-above-MIC-Killer)?
ß-Lactams
What does concentration-dependent-Killer require?
Requires a high antibiotic peak
-Cmax : MIC - 10:1 or greater overall
-AUC/MIC
-Increased drug concentration results in increased bacterial killing
What are the common concentration-dependent-Killers?
Aminoglycosides (Nephrotoxic and ototoxic at high doses), fluoroquinolones, Daptomycin, metronidazole
-CAUTION -> toxicity at high doses
How is efficient dosing of time VS concentration-dependent-Killers explained?
Time-dependent-Killer: The frequency of the dose determines the outcome
->Ticarcilin
Concentration-dependent-Killer: The higher the dose, the better the outcome
-> Tobramycin, Ciprofloxacin
What are Bacteriocidals and Bacteriostatics?
Bacteriocidal: Kills the bacteria
Bacteriostatic: Inhibits growth, and requires intact immune function to kill the bacteria
What are typical Bacteriocidal and Bacteriostatics?
Bacteriocidal: ß-Lactams
Bacteriostatic: Tetracyclines, Macrolides
How does administered drug concentration dictate cidal vs. static
A drug considered bacteriostatic can be cidal if the concentration is high enough
-> Linezol, Macrolides (depending on where the infection is)
