The peak plasma concentration of a drug after administration
What parameter of defines the total drug exposure?
AUC = area under serum concentration time curve
AUC is the time period when:
the concentration in the patient is above the MIC
What type of growth would be indicated for an anti-metabolite?
The growth would increase and then plateau at a lower rate than normal
Pharmacokinetic parameters quantify what?
the serum level time course of an antibiotic
Cmax, Cmin and AUC are all used for what?
To quantify the serum level time course
Cmax, Cmin and AUC were discussed in class as not able to quantify what parameters alone?
Do not quantify the killing activity
Comparing the Plasma level time curve components (e.g. AUC and Cmax) to what other parameter gives us pharmacodynamic efficacy and killing power of the drug?
Cmax:MIC is important to what type drugs?
Conc. dependant drugs
What three pharmacodynamic properties can be used to determine killing properties of a drug?
- Time above MIC
Cmax:MIC, AUD:MIC and time above MIC are pharmacodynamic properties that describe killing in terms of what?
- Time dependence
- persistent effects
- concentration dependence
Cmax:MIC, AUC:MIC and time above MIC are the same for most drugs (T/F)?
False, different for each drug
Rate of killing is determined by what pharmacodynamic factors?
Time above the MIC or the effect of increasing the concentration
Persistent pharmacodynamic effects include:
the PAA, the persistent antimicrobial effects after the antimicrobial is removed
What is the best predictor of killing power?
- 24 hour area under teh curve to MIC ratio or the Peak concentration to MIC ratio
- To prevent resistance what should the peak MIC ratio for Aminoglycosides be?
- peak MIC ratio = at least 8-10 is best to prevent resistance
What 24 hour AUC:MIC is optimal for flouroquinolones against gram negative bacteria?
What 24 hour AUC:MIC is optimal for flouroquinolones against gram + bacteria?
AUC:MIC =40 optimally
Optimal pharmacodynamic ratios are stable from study to study (T/F)?
False, they vary from study to study
What may account for differences across pharmacodynamic ratio studies?
- Missed factors
- Experimenetal error
Pharmacodynamic ratios are very usefulin daily application of susceptibilty (T/F)?
- False, there is too much variation in these ratios
- Not yet reliable
- Different inoculum in the lab than in the patient
The critical determinant for the Pharmacodynamic ratios disscussed in class was: MIC =critical determinant
What is teh standard inoculum for susceptibilty testing in the lab?
- 5x 10^5
- If increase inoculum concentration, what happens to the MIC?
- The MIC dramatically increases
The MIC dramatically increases when you alter what other parameter?
The inoculum concentration
What inoculum that is commonly found in the patient (as disscussed in class) is what?
- A change in inoculum from 5x10^5 to 5 x 10^7 could have an MIC change of what multiplier (as shown in the study)?
- 100s of times higher
The MIC in the lab is always the same as an MIC in the patient (T/F)?
False, it can be drastically different
The pharmacodynamic efficacy of which drugs is Cmax:MIC dependant?
The pharmacodynamic efficacy of which general type of drugs is Cmax:MIC dependant?
Concentration dependant drugs
The pharmacodynamic efficay of what drugs is AUC:MIC dependant?
The pharmacodynamc efficacy of which drugs is Time above MIC dependant?
The pharmacodynamc efficacy of what general type of drugs is Time above MIC dependant?