Anti-Biotics Flashcards
How do tetracyclines work?
Bind to 30s ribosomal subunit and prevent binding of incoming tRNA to A site
What are some conditions we treat w/ oral tetracyclines?
Acne rosacea, MGD, recurrent corneal erosions, non-infectious corneal ulcers
How is tetracycline dosed?
250mg qid for 2-6 wks
Taper
ADR of tetracycline
Hard on the stomach
How is doxycycline dosed?
50-100mg qd-bid
ADR of doxycycline
Photosensitivity
How do macrolides (erythromycin, azithromycin) work?
Bind to 50s ribosomal subunit and inhibit elongation of peptidoglycan chain
How would we treat HS to Staph in children?
erythromycin 250mg qid
How is erythromycin dosed in adults?
500mg qid x 7 days
ADR or oral erythromycin
Gatrointestinal irritation
What is AzaSite?
azithromycin 1% soln
How is AzaSite dosed?
1) 1gt bid x 2 days
2) 1 gt qd x 5 days
(9 drops total!)
How do aminoglycosides work?
Inhibit bacterial protein synthesis
Transported into bacterium, binds to 30s ribosomal subunit
Against which bacterial are aminoglycosides effective?
G(-) - especially pseudomonas Some G(+)
Adverse effects of aminoglycosides
Epithelial toxicity
Allergic reactions
Eyelid edema/erythema
e.g. of Aminoglycosides
Tobramycin 0.3% (soln, ung)
Gentamycin 0.3% (soln, ung)
Neomycin (in combinations)
How do macrolides work?
Inhibit protein synthesis
Bind to 50s ribosomal subunit and inhibit elongation of peptidoglycan chain
Against which organisms are macrolides effective?
G(+) Few G(-)
Macrolide example
erythromycin (ung)
How do cephalosporins work?
Inhibit peptide cross-linking of peptidoglycans polysaccharide chains
(Inhibit cell wall synthesis)
Against which organisms are cephalosporins effective?
G+ only
Eg of cephalosporin
bacitracin
What is Polysporin?
bacitracin + polymixin B ointment
How does polymixin B work?
Destroy cell membrane
