Antibacterial Drugs Flashcards
Concentration dependent drugs concept
Efficacy will increase with increased concentration
Once a day dosing
Cmax: MIC ratio >8
Shows post antibiotic effect
Concentration dependent drugs
Aminoglycosides
Fluoroquinolones
Nitromidazole
Time dependent drug concept
Degree above MIC irrelevant, time above important
Remains above MIC >50% over time
Multi-dosing
Time dependent drugs
Betalactams
Phenicols
Tetracyclines
Rifamycins
Macrolides
Sulfonamides
Bactericidal concept
Kills bacteria
MIC AND MBC the same
Good when immune system not working
Bactericidal drugs
Aminoglycosides
Beta-lactams
Nitroimidazole
Fluoroquinolones
Potentiated sulfonamides
Bacteriostatic concept
Inhibits bacterial growth
MIC AND MBC (higher dose for killing) different
Bacteriostatic drugs
Chloramphenicol
Macrolides
Tetracyclines
Sulfonamides
Cmax
Maximum concentration of drug in a certain part of the body before admin of the 2nd dose
T 1/2
Time it takes for a drug to reduce to half of its initial value
AUC
Total area under the curve
How much drug reaches a person’s bloodstream in a given period of time after a dose is given
Drug synergy
An interaction between two or more drugs that causes the total effect of the drugs to be greater than the sum of the individual effects of each drug.
Drug antagonism.
An interaction between two or more drugs that have opposite effects on the body.
May block or reduce the effectiveness of one or more of the drugs
Challenges with abx in the respiratory tract
Blind areas hard to clear (sinuses)
Bronchus-alveolar-blood barrier
Infection and inflammation (increased distance, inflamm proteins and mucus)
Nebulization options limited
Challenges of the GI tract
Collateral damage by tx (dysbiosis)
Restoring microbiome (nutritional support)
Profoundly sick (SIRS)
Biosecurity
Challenges with the renal system
Early recognition difficult
Alters pH (alter how drug behaves in urine)
Niduses (calculi sources of infection)
Biofilm (destroy or bind to drug)
Polyuria eliminated drug
Rise in MDR bacteria
Intravenous
Best absorption
Critical patients need drugs to take effect ASAP
Challenging, highest cost
Intramuscular or SQ
Good for depot peak plasma concentration, reaches within one hr
Surface area and vascular supply affects systemic availability and peak plasma
Less challenging
Per os (PO)
Has to be absorbed (but not all will be)
Food can bind and reduce medication efficacy (caveat)
GI has to be working
Highest chance for dysbiosis
Least challenging, cheapest
Aerosolized
RLP (region limb perfusion)
IA (intra- articular)
PR (per rectum)
IU (intra uterine)
Topical OS/OD/OU
Why are the 5 Rs of stewardship
Reduction, refinement, replacement, responsibility of vet, review
Refine
Refine the use of an abx agent base on: pathogen, pharmacokinetics, host factors
Replacement
Clear infection without drugs:
Lavage area, incise area, tx underlying condition, supportive care
How to tx wound infections
Good irrigation
NSAID (comfort)
Topical/ local abx: neomycin, bacitracin, silver sulfadiazine
Regional limb perfusion (large animals)
