Lec 6 Clindamycin/Tetracyclines/Chloramphenicol/Quinolones Cushman Flashcards
clindamycin MOA
inhibits protein synthesis by binding to the bacterial 50S ribosome
clindamycin is most effective against (2 things)
1) Aerobic Gram-(+) cocci, including some members of the Staphylococcus and Streptococcus genera.
2) Anaerobic Gram-(–) bacilli, including some members of the Bacteroides and Fusobacterium genera
Clindamycin may be used systemically to treat bone infections with _______ _______ (bacteria), or topically to treat severe acne
staphylococcus aureus
Clindamycin is administered IV with _______ and _______ to treat AIDS patients with _______ caused by Toxoplasma gondii.
pyrimethamine
leucovorin
encephalitis
potentially lethal condition commonly assoc with clindamcyin (2-10% of pts)
pseudomembranous colitis
tx for pseudomembranous colitis assoc with clindamycin (2)
metronidazole or vancomycin
tetracycline is a broad spectrum antibiotic that was found in ____ of Egyptians and Nubians
beer
tetracyclines form stable chelates with polyvalent metal ions such as (4 of them listed)
Ca, Al, Cu, Mg
tetracycline should not be given with what two things (2 examples)
high calcium (milk)
heavy metals (TUMS)
When concomitant therapy with tetracyclines and multivalent metals cannot be avoided, the metals should be administered ___-___ hours after the tetracycline.
1-2
why should children not be given tetracyclines?
teeth discoloration due to chelating calcium
Tetracyclines should be avoided after the ___ month of pregnancy in order to avoid undesirable effects on fetal bones and teeth
4th
Tetracyclines undergo ___ ___ ___ at pH values of 8.5 or above. The _______ product in inactive.
cleavage in base; lactone
tetracyclines MOA (2 things)
-binds to 30S ribosome subunit, blocks attachement of aminoacyl-tRNA to A site of ribosome
-inhibitors of codon-anticodon interaction
tetracyclines most common use
a. gynecomastia
b. acne
c. fever
d. vertigo
b. acne
tetracyclines remain the treatment of choice for infections caused by all of the following EXCEPT:
a. chlamydia
b. Rickettsia
c. brucellosis
d. salmonella
e. spirochetal infections
d. salmonella
tetracycline is produced by fermentation of _______ _______
streptomyces aureofaciens
tetracycline C-6
a. secondary hydroxyl
b. tertiary hydroxyl
c. no hydroxyl
b. tertiary hydroxyl
demeclocycline C-6
a. secondary hydroxyl
b. tertiary hydroxyl
c. no hydroxyl
a. secondary hydroxyl
T or F: tetracycline and demeclocycline absorption is lowered with food and milk
T (take without)
minocycline, doxycycline, tigecycline C-6
a. secondary hydroxyl
b. tertiary hydroxyl
c. no hydroxyl
c. no hydroxyl
what is the significance of the secondary hydroxyl on demeclocycline?
it dehydrates more slowly than tetracycline bc the secondary cation intermed formed is less stable (higher nrg) than the tertiary cation intermed formed from tetracycline
which drug has vestibular toxicities such as vertigo, ataxia, and nausea?
a. tetracycline
b. demeclocycline
c. minocycline
d. doxycycline
e. tigecycline
f. sarecycline
c. minocycline
half-life of 18-22 hours permits once a day dosing
a. tetracycline
b. demeclocycline
c. minocycline
d. doxycycline
e. tigecycline
f. sarecycline
d. doxycycline
what is the significance of the tetracyclines lacking a C-6 hydroxyl?
therefore does not undergo acid-catalyzed dehydration, therefore has no potential for 4-epi…mediated toxicity
T or F: tigecycline is active against gram-positive only
F (both pos and neg)
T or F: tigecycline is available PO and IV
F (IV only)
protected from resistance development due to efflux pump induction and also due to to ribosomal protection proteins
a. tetracycline
b. demeclocycline
c. minocycline
d. doxycycline
e. tigecycline
f. sarecycline
e. tigecycline
weight adjusted dosing
a. tetracycline
b. demeclocycline
c. minocycline
d. doxycycline
e. tigecycline
f. sarecycline
f. sarecycline
interaction with penicillin and tetracyclines
tetracyclines are bacteriostatic and penicillins work
on dividing bacteria; don’t give together
sarecycline use
acne
T or F: dose inc is recommended for sarecycline with anticoagulants and Pgp substrates (digoxin)
F (dec)
sarecycline most common SE
nausea
chloramphenicol MOA: binds reversibly to the ___ ribosomal subunit, inhibits ______ ______ activity of the ribosome and blocks peptide bond formation between the P site and the A site
50S; peptidyl transferase
which of the following is FALSE about chloramphenicol?
a. prodrug is chloramphenicol sodium succinate
b. lipid soluble
c. relatively bound to plasma proteins
d. does not cross BBB
e. indicated for bacterial meningitis and typhoid fever
d. does not cross BBB
which is NOT a resistance mechanism for chloramphenicol?
a. reduced membrane permeability
b. mutation of the 50S ribosomal subunit
c. increased efflux pumps
d. elaboration of chloramphenicol acetyltransferase
c. increased efflux pumps
-most serious toxicity is aplastic anemia
-bone marrow suppression is common
a. omadacycline
b. chloramphenicol
c. levofloxacin
d. clindamycin
b. chloramphenicol
inc risk of childhood leukemia
a. tetracycline
b. chloramphenicol
c. levofloxacin
d. clindamycin
b. chloramphenicol
first gen quinolones have activity against gram _____ bacteria
negative
second gen quinolones have a _______ substituent at C-6 and a heterocyclic ring (usually ________) at C-7
fluorine
piperazine
_________ is the most potent fluoroquinolone showing MIC = 0.01 to 1 µg/mL for Gram-(–) organisms
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. oxolinic acid
a. ciprofloxacin
T or F: second gen quinolones have less activity against gram positive organisms and mycoplasma compared to first gen
F (extended activity)
two discontinued first gen quinolones
oxolinic acid
nalidixic acid
“drug of last resort” due to severe SE
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
c. moxifloxacin
third gen
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
b. levofloxacin
second gen
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
a. ciprofloxacin
fourth gen
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
c. moxifloxacin
used topically to treat impetigo due to staph aureus or strep pyogenes
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
d. ozenoxacin
oral or IV use for tx of skin infections
a. moxifloxacin
b. ozenoxacin
c. delafloxacin
c. delafloxacin
DNA _______ is blocked by the quinolones
a. folding
b. religation
c. cleavage
d. binding
b. religation
increasing resistance to quinolones has led to which drug being first line for neisseria gonorrhoeae?
a. cefipime
b. cefdinir
c. ceftriaxone
d. cephalexin
c. ceftriaxone
effective against chlamydia trachomatis
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
b. levofloxacin
__________ as a sole therapy is effective in 50% of diabetic foot infections.
ciprofloxacin
effective against haemophilus ducreyi
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
a. ciprofloxacin
resistance to fluroquinolones (3 things)
- decreased cellular permeability
- efflux pumps
- point mutations of enzymes
fluoroquinolone resistance: which is more common, point mutations in the A or B subunit of the DNA gyrase?
A
T or F: if you are resistant to one fluoroquinolone, you can switch to another of the same class
F (cross resistance, but not with other classes of antibiotics)
T or F: fluoroquinolones and tetracyclines should NOT be given with foods and drugs containing heavy metals
T
__________ has been associated with hyperglycemia and hypoglycemia in diabetic patients
a. ciprofloxacin
b. levofloxacin
c. moxifloxacin
d. ozenoxacin
e. gatifloxacin
e. gatifloxacin
T or F: tetracyclines can cause damage growing cartilage and cause tendon rupture
F (fluoroquinolones)
can be used to treat pseudomonal infections with children with cystic fibrosis
a. clindamycin
b. tetracyclines
c. chloramphenicol
d. fluoroquinolones
d. fluoroquinolones
