Antibiotics Shuffled Flashcards
How is imipenem metabolized?
it is inactivated by renal dipeptidase
How do bacteria develop resistance against fluoroquinolones?
they modify their DNA gyrases
What are the major side effects of vancomycin?
- it enhances the ototoxicity and renal toxicity of aminoglycosides
- it triggers histamine release to cause “red man” syndrome
List the four important anti-pseudomonas penicillins.
- ticarcillin
- mezlocillin
- piperacillin
- carbenicillin indanyl
What is the primary urinary tract antiseptic currently in use?
nitrofurantoin
What is the major side effect of ethambutol?
it has a dose-dependent optic neuritis that affects red-green differentiation and visual acuity
What is the mechanism of action for penicillins?
- mimic PBP ligand and irreversibly inhibit transpeptidase
- activate murein hydrolases
How is isoniazid used clinically?
- alone for TB prophylaxis
- in combination for TB treatment
Vancomycin is a preferred treatment for which two difficult to treat infections?
- MRSA
- C. diff
How does MRSA achieve beta-lactam resistance?
it altered PBP structure, so penicillin could no longer bind
In what cases does nitrofurantoin cause side effects?
cleared so quickly, it has none unless the individual has a renal insufficiency
What is the mechanism of action of fosfomycin?
it inhibits the cytoplasmic step of cell wall precursor synthesis
How is rifampin used clinically?
- in combination for active TB
- alone for TB prophylaxis if isoniazid isn’t an option
What are the major side effects of cephalosporins?
- renal toxicity (enhanced by ahminoglycosides)
- inject site reaction
- moderate cross-reactivity with PCN-sensitive patients
- disulfiram effect with bleeding disorders (mostly cefotetan and cefoperazone)
What is the clinical utility of macrolides?
they are used for gram+ infections in PCN-sensitive patients
What is the mechanism of action of oxazolidinones?
they inhibit 70s ribosomal formation
What is the mechanism of action of imipenem?
it is a beta-lactam
What are the adverse effects of sulfonamides?
- Steven-Johnson syndrome reaction
- hematuria
- hematopoietic effects
What is the mechanism of action of cephalosporins?
they are beta-lactams
What are the side effects of trimethoprim? How do we compensate for this?
- anemia, leukopenia, etc.
- administer with folinic acid
What are the limitations of polymixins?
they have systemic toxicity and are therefore restricted to topical applications or as salvage therapy for highly resistant bacteria
What is co-trimoxazole?
trimethoprim-sulfamethoxazole combination therapy
What is special about the distribution of aztreonam?
it crosses the BBB
How do we use trimethoprim clinically?
- monotherapy for UTI
- with a sulfonamide (co-trimoxazole) otherwise