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35 Cards in this Set
- Front
- Back
What is the mechanism of action of penicillin?
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Block cell wall synthesis
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Bacteristatic antibiotics are effective in immunocompromised individuals.
True or False? |
False
Bactericidal are effective |
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What is the mechanism of action of amoxicillin?
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Blocks cell wall synthesis
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Which penicillins are resistant to penicillinase?
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Nafcicillin, oxacillin,dicloxacillin,and ampicillin
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Which drug blocks the activity of ß-lactamase?
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Clavulanic acid
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This class of ß-lactam antibiotics is resistant to many ß-lactamases and has a wider spectrum of activity.
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Cephalosporins
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Name a first generation cephalosporin that is orally active.
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Cefalexin
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Name two third generation cefalosporins.
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Ceftriaxone
Cefotaxime |
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Vancomycin
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Active against gram + organism
Blocks cell wall synthesis Bactericidal MRSA |
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Name 3 macrolide antibiotics.
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Azithromycin, erythromycin, clarithromycin
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What is the mechanism of action of macrolide antibiotics?
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Binds to 50S ribosome to prevent protein synthesis
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Name three classes of antibiotics that are protein synthesis inhibitors.
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Macrolides, aminoglycosides, and tetracyclines
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What is the mechanism of action of doxycycline?
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Binds to the 30S ribosome to prevent protein synthesis
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What is the mechanism of resistance to tetracycline antibiotics?
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Efflux pump
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What is the mechanism of action of aminoglycosides?
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Binds to 30S ribosome to prevent protein synthesis
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What are the toxicities of aminoglycosides?
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Ototoxicity
Nephrotoxicity |
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What is the mechanism of action of linezolid?
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Binds to 23S ribosomal unit of the 50S ribosome
No cross resistance Reserved for severe infections like Vanco |
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Name two fluoroquinolones.
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Ciprofloxacin
Levofloxacin |
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What is the mechanism of action of ciprofloxacin?
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Blocks uncoiling of DNA by preventing the action of topoisomerase II and IV
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How does resistance to levofloxacin develop?
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Mutations of the binding side on the topoisomerase
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What is the mechanism of action of rifampin and what are its characteristic features?
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Binds to DNA dependent RNA polymerase to inhibit RNA synthesis
Red/orange urine Resistance almost always develops if given alone |
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What is the mechanism of action of trimethoprim-sulfamethoxazole?
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Blocks folic acid synthesis by inhibiting DHFR
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Which AIDS defining infection is TMP/SMX effective against?
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Pneumocystitis pneumonia
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What is the major basis for selective toxicity in antifungal drugs?
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Ergosterol is the major membrane lipid in fungi, compared to cholesterol in mammals
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What is the mechanism of action of amphotericin B?
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Bind to ergosterol and alters membrane permeability
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What is the major toxicity of amphotericin B?
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Nephrotoxicity
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What is the mechanism of action of flucytosine?
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Inhibitions thymidylate synthase, preventing DNA synthesis?
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What is the basis for the selective toxicity of flucytosine?
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We do not have cytosine deaminase and are unable to take up flucytosine
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What is one of the toxicities of flucytosine?
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Reversible neutropenia
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What is the mechanism of action of caspofungin?
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Blocks the synthesis of Beta (1,3)-d-glucan, a polysaccharide in fungal cell walls
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What is the mechanism of action of "azole" antifungals?
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Blocks the synthesis of ergosterol, by:
inhibiting the fungal enzyme sterol 14-α-demethylase, a CYP450 enzyme |
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What is the mechanism of action of terbinafine?
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Inhibits squalene epoxidase, leading to an accumulation of squalene, which is toxic to fungi
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What is the basis for the selective toxicity of "azole" compounds?
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Greater affinity for fungal CYP450 enzymes
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What are the consequences/toxicities of "azole" compounds?
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CYP450 inhibition - drug interaction
Gynecomastia, infertility, menstrual irregularities |
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Name three triazole compounds and explain why they are important.
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Fluconazole, itraconazole, voriconazole
These are becoming the preferred treatment due to slower metabolism and less effects on human sterol synthesis |