Miscellaneous Flashcards
What is a drug (human) under the nitromidazole class? Formulations?
Metronidazole (human products)
- oral, IV and topical cream
What is the MOA of metronidazole?
intracelljlar anaerobic metabolism of drug produced reactive metabolites = DNA damage
What is the SOA of metronidazole?
Anaerobes (clostridium, bacterioides, brachyspira)
protozoa (trichomonas, campylobacter)
limited against aerobes
Can resistance occur with Metronidazole?
rare, but can with intracellular drug activation
- cross resistance between nitromidazoles
what is the PK of metronidazole?
good oral F
penetrates many tissues (incl CSF and bone)
eliminated: hepatic metabolism, excreted bile and urine
What are the AEs of metronidazole?
potential carcinogen (banned in food)
may be teratogenic (not for pregnant)
minimal GI upset (salivation, inappetence)
neuro: ataxia, seizures, lethargy (Tx: Diazapam)
Drug interactions:
- caution when using with microsomal enzyme (CYP) inducer/inhibitor
What are 2 drugs in the nitrofuran class?
Nitrofurazon (topical vet)
- wound cream (not for food animals)
Nitrofurantoin (oral human)
- e.coli/MDR UTIs in dogs and cats
What antimicrobial can be used to treat e.coli/MDR UTIs?
Nitrofurantoin
what is the MOA of nitrofurans?
block bacterial pyruvate metabolism (no energy)
what is the SOA for nitrofurans?
broad
especially gram - enterics
What is the problem with nitrofuran effectiveness?
reaching MIC levels in plasma requires dose that causes systemic toxicity
Is resistance a problem with nitrofurans?
does occur (not common) - no cross resistance with other classes
What is the PK of nitrofurans?
good oral absorption
topical absorption unknown
wide distribution
excretion: renal (high concentrations in urine (even low dose)
What are the AEs of nitrofurans?
cardiomyopathy (ventricular dilation)
reproductive (endocrine) toxicity
carcinogenic (banned in food animals)
What Rifampin formulations are used?
human tablets
What is the MOA of Rifampin?
inhibits bacterial RNA polymerase penetrates leukocytes (well for intracellular)
What is the PK-PD relationship for Rifampin?
bacteriostatic
time dependent activity
What is the SOA of Rifampin?
broad but high resistance (esp gram - )
What are common infections Rifampin would be used to teat?
Mycobacterium (TB)
staph isolates
rhodococcus equi (pneumonia in foals)
Is resistance a problem with Rifampin? How? what can be used in conjunction to avoid resistance?
emerges quickly
- single amino acid change in bacterial RNA polymerase reducing binding on antibiotic
use along with erythromycin or others
what is the PK of Rifampin?
good oral F
wide distribution to variety of tissues
hepatic metabolism
biliary and renal excretion
What are the AE of Rifampin?
red tinged fluides (urine, sweat, saliva) - no concern
Hepatic CYP and P-gyp enzyme induction (increases clearance of other drugs)
teratogenic
Blood dyscrasias (rare) - anemia, decrease platelets
What glycopeptide antimicrobial should not be used in vet med?
vancomycin (oral, injectable)
What is the MOA of vancomycin?
inhibits peptidoglycan synthesis for cell wall
What is the SOA for vancomycin?
gram + rods and cocci (especially MRS, enterococcus)
Gram - typically resistant
Is resistance a concern? what is the mechanism?
MAJOR health human concern
- vancomycin resistant enterococci (VRE)
- MRSA with decrease susceptability to vacomycin
plasmid binding VanA gene changes target binding
What is the PK on vancomycin?
poor oral F
limited tissue distribution
excreted via glomerular filtration (renal failure patient)
What is the MOA of Polymyxin B?
cationic detergents
- binds to cell membrane and disrupts its tructure
What is the SOA of Polymyxin B?
gram - only
What are the AE of Polymyxin B?
wide range of toxicity with systemic admin
How should Polymyxin be be administered?
topically (otic or opthalamic) or IMM
What other use is their for Polymyxin B?
endotoxin binding effects
What is Bacitracin (BNPH)? use? formulations?
“topical b-lactam” - same mechanism
use: gram + bacteria
also
- premixes in poultry and swine (growth and prevention of enteritis)
What is the MOA, use and PK of Mupirocin? what is the human drug name?
human fromulations
MOA: blocks bacterial protein synthesis
PK: rapidly metabolized after systemic administration
Form: topical (for staph infections), intranasal for MRSA
good penetration into infected tissues
Muricin
USE: pyoderma in dogs
What are drugs we should not use in Vet Med?
Linezolid
- last resistance saved for humans
Colistin
- related to polymyxin B
- used in china for swine
- lead to high resistance and zoonotic risk
