B&B: Other antibiotics Flashcards
Quinolones
Ciprofloxacin
Levofloxacin
Moxifloxacin
Norfloxacin
Quinolones
Inhibit enzymes for bacterial DNA synthesis
- DNA gyrase
- Topoisomerase IV
All Quinolones have
a double ring structure
Most Quinolones have
fluorine attached
Bacterial Topoisomerase enzymes
DNA Gyrase and Topoisomerase IV
DNA Gyrase
Introduces ds break
Repairs break
Topoisomerase IV
Separates daughter chromosomes
Decantenation
Inhibition of bacterial topoisomerase enzymes causes
DNA damage and cell death
Quinolone resistance mechanisms
Alterations of DNA gyrase and topoisomerase IV
Alteration in cell permeability
Efflux of drug
Quinolones
Many gram (+), gram (-), atypicals
Common clinical uses (adults only)
-UTI (E. coli, other enteric gram negatives)
-Pneumonia (S. pneumo, H. flu, atypicals)
-Abdominal infections (enteric gram negatives)
Naladixic acid (not a fluoroquidinone), Norflaxin
One of first Quinolone drugs
Mostly gram (-) coverage
Limited/no gram (+) coverage
Ciprofloxacin
Quinolone Some gram (+) coverage -Rarely used alone for gram (+) due to resistance -Good gram (-) coverage -Most reliable pseudomonas coverage -Used in UTIs, GI infections -Cipro ear drops for otitis externa
Levofloxacin
Quinolone
More gram (+)/atypical coverage than Cipro
-Better strep pneumo coverage than Cipro
-Covers most methicillin resistant staph aureus
Less effective against pseudomonas than Cipro
Commonly used in pneumonia (strep, atypicals)
Quinolones: Adverse Reactions
GI upset
-Anorexia, N/V, abdominal discomfort
Neuro
-HA, dizziness
Quinolones: Adverse Reactions
Qt prolongation on EKG
Caused by blockage of K+ channels
Can lead to torsades de pointes
Vancomycin
Inhibits peptidoglycan formation (cell wall)
Binds D-analyl-D-alanine peptides
Prevents crosslinking
When cell wall formation is greater than cell formation, cell dies
Vancomycin has the same effect but via different mechanism in regards to what drug
beta lactams (inhibit transpeptidases) Vancomycin blocks transpeptidase binding
Vancomycin resistance
Terminal amino acids change
-D-alanyl-D-alanine changes to D-alanyl-D-lactate
VRSA emerges
Vancomycin is only effective in
Gram (+)
Too large to pass outer membrane gram negatives
Vancomycin Common uses
- Methicillin Resistant Staph Aureus (MRSA)
- Oral therapy for C. difficile pseudomembranous colitis
Often given empirically when MRSA is a concern
-Endocarditis
-Severe pneumonia/sepsis
Vancomycin adverse effects
Generally well tolerated
Nephrotoxicity
-Increased risk with concomitant aminoglycoside therapy
Ototoxicity (rare)
Red Man Syndrome: Direct activation of mast cells releases histamine. Pseudoallergic drug reaction. Slow infusion = no symptoms.
Nitrofurantoin
Rarely used antibiotic
MOA not understood
Bactericidal drug
Only use for UTIs (concentrates urine)
Can Nitrofurantoin be given during pregnancy.
Yes. Administer for UTIs during pregnancy. Avoid TMP-SMX, Quinolones.
What can Nitrofurantoin trigger in G6PD patients?
hemolysis
