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35 Cards in this Set

  • Front
  • Back
What is the mechanism of action of penicillin?
Block cell wall synthesis
Bacteristatic antibiotics are effective in immunocompromised individuals.

True or False?
False

Bactericidal are effective
What is the mechanism of action of amoxicillin?
Blocks cell wall synthesis
Which penicillins are resistant to penicillinase?
Nafcicillin, oxacillin,dicloxacillin,and ampicillin
Which drug blocks the activity of ß-lactamase?
Clavulanic acid
This class of ß-lactam antibiotics is resistant to many ß-lactamases and has a wider spectrum of activity.
Cephalosporins
Name a first generation cephalosporin that is orally active.
Cefalexin
Name two third generation cefalosporins.
Ceftriaxone

Cefotaxime
Vancomycin
Active against gram + organism

Blocks cell wall synthesis

Bactericidal

MRSA
Name 3 macrolide antibiotics.
Azithromycin, erythromycin, clarithromycin
What is the mechanism of action of macrolide antibiotics?
Binds to 50S ribosome to prevent protein synthesis
Name three classes of antibiotics that are protein synthesis inhibitors.
Macrolides, aminoglycosides, and tetracyclines
What is the mechanism of action of doxycycline?
Binds to the 30S ribosome to prevent protein synthesis
What is the mechanism of resistance to tetracycline antibiotics?
Efflux pump
What is the mechanism of action of aminoglycosides?
Binds to 30S ribosome to prevent protein synthesis
What are the toxicities of aminoglycosides?
Ototoxicity

Nephrotoxicity
What is the mechanism of action of linezolid?
Binds to 23S ribosomal unit of the 50S ribosome

No cross resistance

Reserved for severe infections like Vanco
Name two fluoroquinolones.
Ciprofloxacin

Levofloxacin
What is the mechanism of action of ciprofloxacin?
Blocks uncoiling of DNA by preventing the action of topoisomerase II and IV
How does resistance to levofloxacin develop?
Mutations of the binding side on the topoisomerase
What is the mechanism of action of rifampin and what are its characteristic features?
Binds to DNA dependent RNA polymerase to inhibit RNA synthesis

Red/orange urine

Resistance almost always develops if given alone
What is the mechanism of action of trimethoprim-sulfamethoxazole?
Blocks folic acid synthesis by inhibiting DHFR
Which AIDS defining infection is TMP/SMX effective against?
Pneumocystitis pneumonia
What is the major basis for selective toxicity in antifungal drugs?
Ergosterol is the major membrane lipid in fungi, compared to cholesterol in mammals
What is the mechanism of action of amphotericin B?
Bind to ergosterol and alters membrane permeability
What is the major toxicity of amphotericin B?
Nephrotoxicity
What is the mechanism of action of flucytosine?
Inhibitions thymidylate synthase, preventing DNA synthesis?
What is the basis for the selective toxicity of flucytosine?
We do not have cytosine deaminase and are unable to take up flucytosine
What is one of the toxicities of flucytosine?
Reversible neutropenia
What is the mechanism of action of caspofungin?
Blocks the synthesis of Beta (1,3)-d-glucan, a polysaccharide in fungal cell walls
What is the mechanism of action of "azole" antifungals?
Blocks the synthesis of ergosterol, by:

inhibiting the fungal enzyme sterol 14-α-demethylase, a CYP450 enzyme
What is the mechanism of action of terbinafine?
Inhibits squalene epoxidase, leading to an accumulation of squalene, which is toxic to fungi
What is the basis for the selective toxicity of "azole" compounds?
Greater affinity for fungal CYP450 enzymes
What are the consequences/toxicities of "azole" compounds?
CYP450 inhibition - drug interaction

Gynecomastia, infertility, menstrual irregularities
Name three triazole compounds and explain why they are important.
Fluconazole, itraconazole, voriconazole

These are becoming the preferred treatment due to slower metabolism and less effects on human sterol synthesis