Pharmacology Flashcards
MOA for Bacitracin
inhibits transfer of transpeptidase into growing bacterial cell wall
Drugs that inhibit protein synthesis by binding to 30S subunits
Aminoglycosides
Tetracyclines
Drugs that inhibit bacterial protein synthesis by binding to the 50S subunit
Chloramphenicol, macrolides, clindamycin
Drugs that inhibit folic acid synthesis
Sulfonamides
Trimethoprim and pyrimethamine
MOA for fluoroquinolones
inhibits DNA gyrase and topoisomerase IV
Side effects of oral antibiotics
GI effects (nausea, vomiting, bloating, decreased appetite, diarrhea)
MOA of penicillins and cephalsporins
inhibit cell wall synthesis by inhibiting transpeptidase
Bacitracin only effective against which bacteria & how would you prescribe it?
gram + , QD - TID for blepharitis
amoxicillin
- MOA inhibits transpeptidase
- better gram (-) coverage
- NOT resistant to penicillinase
What does dicloxacillin and augmentin treat?
hordeola, preseptal cellulitis
Which drugs are penicillinase resistant?
- oxacillin
- dicloxacillin
- cloxacillin
How is Augmentin prescribed?
500 mg , 875 mg, 1,000 mg tabs BID x 1 week
Dicloxacillin
- best for methicillin-sensitive staph aureus (MSSA)
- NOT effective for staphylococcal strain (MRSA)
Adverse effects for penicillin
- urticaria & anaphylaxis (IgE mediated type 1 reaction) to contact dermatitis (type 4)
- render oral contraceptives ineffective
- Stevens-Johnson syndrome in pts taking amoxicillin
Why are patients usually allergic to both cephalosporins & penicillins?
They both have beta-lactam ring
Cephalosporin - 6 ring
Penicillin - 5 ring
1% risk that the pt is allergic to BOTH
Contraindicated in pt with hx of IgE type 1 hypersensitivity rxn (urticaria & anaphylaxis)
Cephalosporins MOA
Inhibit transpeptidase
what is cephalexin used to tx for?
skin infections caused by gram + bacteria - dacryadenitis, dacryocystitis, and preseptal cellulitis - SHOULD NOT BE USED IN ISOLATION W/ MRSA
Dosage for cephalexin
250-500mg BID to QID for the tx of dacryocystitis, dacryadenitis, & preseptal cellulitis
What is ceftriaxone used to tx?
tx gonorrhea conjunctivitis & orbital cellulitis
Ceftriaxone dosage for gonococcal conjunctivitis corneal involving and noninvolving
Involving - IV every 12-24 hours for 3 days
Non-involving - single 1 gram IM injection
Ceftriaxone dosage for orbital cellulitis
1 gram IV qday x 1 week
Adverse effects for cephalosporins
destroy normal micrflora - alters absorption of vitamin K causing “thinning” of blood in pts taking warfarin (Vit K antagonist)
Gram coverage for cephalpsporins
1st gen: gram (+)
2nd gen: gram: some(-) & (+)
3rd gen: gram (-) & (+)
Gram coverage for aminoglycosides
gram + and -, better gram - coverage
List Aminoglycosides & MOA
TobraGent30
Gentamycin
Tobramycin
Inhibit binding of 30s ribosomal subunit
What is tobradex used to tx?
inflammation w/ bacterial infection (staph marginal keratitis, corneal infiltrates)