Lecture 10 - Pharmcodynamics of Antibiotics Flashcards
Why is antibiotic optimization important?
It’s good for the patients and for avoiding resistance
What are important steps to take throughout antibiotic therapy?
Initiating empirical broad-spectrum antibiotics
Narrowing empirical antibiotics from “broad” to “targeted”
De-escalating antibiotics from “empirical to “definitive
Optimizing antibiotic dosing
Stepping down antibiotic from “parenteral” to “oral
Using appropriate duration of antibiotic therapy
What does initiating empirical broad spectrum antibiotics mean?
Using an antibiotic that covers everything (you don’t want to miss out on the bug that’s causing the infection; the blood culture takes 24-48 hours, which could be too long)
What does narrowing empirical antibiotics from “broad” to “targeted” mean?
Preliminary laboratory results can allow us to change the narrow down the antibiotics (ex. if the bacteria is gram positive or gram negative)
What does narrowing from “empirical” to “definitive” mean?
Once the final laboratory results are available, antibiotic therapy can be changed towards the specific organism causing the infection (ex. MRSA)
Why is optimizing antibiotic dosing so important?
Not giving enough antibiotic, the drug can fail (and low levels can cause resistance)
What is the importance of pharmacokinetics in antibiotic therapy?
It’s measuring the drug in the blood stream (it’s mathematical)
What is the importance of pharmacodynamics in antibiotic therapy?
It tells us what the numbers provided by PK mean in a patient (what do those levels mean?)
What is AUC?
Area under the curve (provided by PK; extremely important)
What is MIC
Minimum inhibitory concentration
What happens when you divide the AUC by the MIC
It gives us a PK diameter or index. The higher the AUC/MIC, the better chance of survival
What are the requirements for stepping-down antibiotics from “parenteral” to “oral”
Adequate response to initial IV therapy
Appropriate oral antibiotics
Patient adherence (stopping early is a risk factor for resistance; adherence is especially appropriate for out-patients)
Follow-up
How is the appropriate duration of antibiotic therapy determined?
It depends on the patient and how they respond, but we do resort to guidelines
What does empirical antibiotic therapy mean?
Using antibiotics before having any information about what you are treating
What is broad empirical therapy?
Therapy that covers as many possible pathogens
