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8 Cards in this Set
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- Back
- 3rd side (hint)
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Aminoglycosides
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Streptomycine
gentamicin tobramycin amikacin neomycin |
exact mechanism of action is unkown. Act at level of ribosome to inhibit protein syntehsis or cause misreading and faulty protein production. Have concentration dependent killing, act synergistically with other antibiotics and have post antibiotic effect
Spectrum of activity-very good against aerobic and facultative gram negative rods. Streptomycin is best againt mycobacterium tuberculosis and yersinia pestis, amikacin is good against mycobacterium and mycobacterium avium intracellulare. Spectinomycin is used agains neisseria gonorrhoaea.Neomycin is used as bowel prep before GI surgery. Gentamicin and streptomycin are synergistic with penicillin against enterocoocci and penicillin resistant strep. Resistance can occur through ribosomal resistance with the ribosome changing but this is rare. It can have decreased uptake of the drug, also uncommon. Through aminoglycoside modifying enzymes, most common. Some can be aminoglycoside resistant enterococci Aminoglycosides are poorly absorbed in the GI, poor concentration in CSD and eye, crosses placenta, excreted renally, need to monitor levels Toxcicity-neyromuscular blockade causing paralysis, ototoxicity, nephrotoxicity |
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Tetracycline
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MOA-binds to 30 s subunit blocking addition of new AA
Is a broad spectrum used in acne, rickettsia, chlamydia, mycoplasma, cholera, brucella, lyme, and mycobacterium marinum. well absorbed in GI, renally excreted anc crosses BBB and blacenta. found in breast milk toxicity-hypoplasia of tooth enamal, GI irritation, hepatotoxicity, renal disease, veritgo interactions-decreased absorption with Ca, Mg, or AL, antacids, milkd, sodium bicarb, iron. DIlantin and barbituates decrease half life. Methoxyfluorine can cause nephrotixicity when combined with tetracycline |
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chloramphenicol
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MOA-binds to 50S subunit blocking binding of aminoacyltRNA
broad spectrum Resistance through impermeable to drug or acetylates drug to inactive form well absorbed from GI, metabolized by liver, wide distribution-cns, tears, placenta, reduce for liver failure toxicity-hematologic, gray syndrome-neonate with abdominal distension, flaccidity, cyanosis, can lead to death. optic neuritis used for brain abscess, meningitis, typhoid fever, rocky mountain spotted fever, |
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Erythromycin
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binds to 50S subunit of ribosome
primarily against gram positive bacteria destroyed by gastric acid, decreased absorption with food, corsses bood/brain barrier toxicity-GI, phlebitis, cholestatic hepatitis, transient hearing loss |
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Clarithromycin
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two to four times better against strep and staph. Possible decreased GI toxicity, well absorbed
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Azithromycin
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two to fourfold less active than erythro against staph and strep. similar spectrum but more activy agasint H flu and salmonella/campylobactor. decreased with food, long half life. active against chlamydia
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Clindamycin
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binds to 50S subunit
very actives against anaerobic bacteria and gram positive 90% gi absorption, not decreased by food, penetrates most tissue but poor CSF, metabolized by liver toxcicity- 20% diarrhea, psuedomembranous colitis used for anaerobic infection, toxo |
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Linezolid
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binds to 50S subunit
active against gram positive well absorbed form GI, 80% in urine toxicity-decreased platelets, is weak MAOI used for penicillin resisitant S. pneumoniae, methicillin resistant and canomycin intermediate staph and vancomycine resisitant enterococci |
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