Antibacterial Drugs - General Flashcards
what does bacteriocidal mean
a drug that KILLS bacteria independent of host immune function
what does bacteriostatic mean
a drug that INHIBITS bacterial growth and division; immune system can then more rapidly eradicate the non multiplying bacteria
what drugs are time dependent AMDs (6)
-beta lactams
-tetracyclines
-sulphonamides
-TMS
-most macrolides
-other static AMDs
what does it mean by time dependent AMDs
efficacy is associated with length of time drug concentration remains above MIC
what does it mean by concentration dependent AMDs
efficacy depends on peak concentration
what drugs are concentration dependent AMDs (4)
-aminoglycosides
-fluoroquinolines
-metronidazole
-azithromycin
what route of administration can you not use in ruminants for AMDs? why?
cant be administered orally
1) may be destroyed in the rumen
2) may destroy rumen microflora causing rumen stasis
what age of ruminant can you give AMDs to orally?
pre-ruminant calves
what do you have to be aware of with AMDs in hindgut fermenters
Some drugs that are safe to administer parenterally will, if given orally, trigger the release of toxins from gut bacteria
* These toxins may be lethal
what does AMR vary with?
time and geographic location
what is penicillin G effective against
gram +ve aerobes, anaerobes
what test can be used to determine susceptibility?
kirby bauer disk diffusion test
each drug is then split into sensitive, resistant or intermediate
when is culture and sensitivity testing done
-for most life threatening infections (or high risk of permanent damage)
-also done when non critical infection is resistant to empirical therapy (complicated infections)
5 considerations when selecting a drug
1) bacterial sensitivity; use narrow spectrum drugs when possible, to avoid selecing for AMD resistant commensal bacteria
2) bacteriostatic vs bactericidal; may require bactericidal drug if immune system is compromised
3) adverse effects; the need for the drug should outweigh the likely adverse effects
4) distrubution; not all drugs enter CNS and prostate readily
5) cost
what to consider with AMDs and abscesses
AMD may not enter the abscess or may be inactivated by it so draining it is likely more effective than using an AMD
if no systemic illness, drug probs not needed
what does the drug need to do for intracellular pathogens
needs to readily enter cells
medical examples for prophylactic use of AMDs (2)
-high risk of serious infection following trauma
-patients condition will allow a serious infection (immune system deficiency)
surgical examples for prophylactic use of AMDs (5)
- Open GI tract
- Head & neck
- Joint
- Hysterectomy/C-section
- Cardiac, thoracic, prosthetic, implant
what is the goal of AMD levels for surgery?
The goal is to have adequate AMD levels in tissue at time of incision
- Administer at or following induction
- Administer every 2 half-lives during surgery
