Intro to Antibiotics Flashcards
What is a broad spectrum antibiotic?
It is active against gram positive AND gram negative bacteria and it increases resistance.
What is a narrow spectrum antibiotic?
It is active against gram positive OR gram negative.
What does bactericidal mean?
- Kills bacteria
- Reasonably achievable tissue concentration that is greater than the minimum bactericidal concentration (MBC.)
What does bacteriostatic mean?
- Stops growth or replication of bacteria
- Reasonably achievable tissue concentration that is greater than the minimal inhibitory concentration (MIC.)
What do you need for a bacteriostatic drug to work?
You need a competent immune system.
What does MIC stand for?
Minimal Inhibitory Concentration
What does MBC stand for?
Minimum Bactericidal Concentration
When are time-dependant antibiotics most effective?
When the level of drug remains above a certain cut-off for a significant portion of the day.
T > MIC is greater than _____% of the dose interval?
40 - 50%
When are concentration-dependant antibiotics most effective?
When a high leave of the drug is reached, often above an absolute cut-off. Does not need to be maintained for any specific amount of time.
What does PAE stand for?
Post - Antibiotic Effect
Concentration-dependant drugs have a ______ that causes continued organism suppression even after drug levels drop.
Post - Antibiotic Effect
Cmax / MIC > ______?
8-12
What is the “third - category” of dose - dependent drugs?
Some drugs have efficacy correlated with total body exposure to the drug (estimated by the AUC.)
AUC / MIC > 125
What does AUC stand for?
Area Under the Curve
What are the MOA of x-dependent drugs? (4)
- Inhibition of cell wall synthesis
- Disruption of cell membranes
- Inhibition of protein synthesis
- Inhibition of DNA synthesis / function
Generally, drugs that inhibit the cell wall are low toxicity drugs. What drug is an exception?
Bacitracin. It is extremely nephrotoxic so it is only used topically.
What are some B - lactam antibiotics?
Penicillins, Cephalosporins, Carbapenems and Monobactams, B - lactamase inhibitors.