Antibacterial Agents III Flashcards
The three macrolides are ___________.
azithromycin, clarithromycin, and erythromycin
What are the important considerations for hepatically metabolized drugs?
(1) drug-drug interactions; (2) genetic differences in metabolism; and (3) potential for hepatotoxicity
All of the protein-synthesis inhibitors are bacteriostatic except __________.
the aminoglycosides, which irreversibly bind to the 30S subunit
The tetracyclines bind to the _________, as do aminoglycosides.
30S subunit
Chloramphenicol and the macrolides bind to the ____________.
50S subunit
Resistance to tetracycline is commonly accomplished by _________.
acquisition of DNA that expresses proteins for efflux pumps
Tetracycline absorption is impaired by _________.
milk products, Al3+, Ca2+, Mg2+, and Fe2+
Chemically, macrolides are __________.
weak bases that are more active at alkaline pHs
Drug inactivation does not occur with __________.
macrolides
Resistance to macrolides can occur by _________.
drug efflux or methylation of the 50S subunit
Which macrolide should be taken on an empty stomach?
Azithromycin
Azithromycin and erythromycin cannot reach the _______, but they can pass to the ________.
CSF; placenta
Which macrolide can be dosed once daily?
Azithromycin
Macrolides can kill ____________.
Gram-positive cocci (except enterococci), many Gram-negative bacteria (H. influenzae, Neisseria, Leionella, Bortadella), and atypical bacteria
What are the three ways bacteria become resistant to tetracyclines?
Decreased entry, increased efflux, and modified protein target (30S)
Tetracyclines are best absorbed on _________ stomach.
an empty
Tetracyclines work great for everything except ___________.
Enterococci, Clostridia, Pseudomonas, and H. influenzae
Vibrio cholerae is a ___________.
Gram-negative bacillus
Other than macrolides, _________ also binds to the 50S subunit.
clindamycin
Clindamycin mostly works just on __________, but also works on _________.
Gram-positive cocci (except enterococci); Bacteroides fragilis
List the aminoglycosides.
Streptomycin, Tobramycin, Gentamicin, Amikacin, Kanamycin, and Neomycin
Aminoglycosides are ________ soluble and more active at ___________.
water (hence, they do not penetrate tissues well); alkaline pH
The three ways bacteria become resistant to aminoglycosides are __________.
decreased entry, modified drug target, and enzymatic drug modification
Because they are polar and cationic, _____ are not well absorbed orally.
aminoglycosides
Aminoglycosides work well against __________.
Gram-positive cocci (except enterococci) and Gram-negative rods (except H. influenzae); they are not effective against atypical or anaerobic bacteria
Again, aminoglycosides are very toxic to the __________.
kidneys and inner ears
Because it is so lipid soluble, _________ is rapidly absorbed and well distributed to all tissues.
chloramphenicol
Chloramphenicol is best at treating _________.
Gram-negative bacteria, anaerobes, and atypical bacteria
Toxic effects of chloramphenicol include ___________.
grey baby syndrome and bone marrow toxicity
_________ also inhibit the 50S subunit, but because they do so at a different site, no cross-resistance has been observed.
Linezolids
Clarithromycin has a ________ duration than erythromycin.
longer
How would you treat community-acquired pneumonia in a healthy person, a person who had had abx within the past three months, and a person in the ICU?
Healthy = doxycycline or a macrolides; previous abx = fluoroquinolone or macrolide + beta-lactam; and ICU = pip/taz + fluoroquinolone or vancomycin
The only drug that treats Lyme disease is __________.
doxycycline
Clindamycin can cause ___________.
pseudomembranous coitis
Iron supplements decrease the bioavailability of ____________.
tetracyclines
The cyclines are __________.
teratogenic
