Lecture 3 Clinda/Tetra/Chlorem Flashcards
Clindamycin binds the ___ part of the ____ ribosome, inhibiting protein synthesis.
23s RNA; 50S
Clindamycin is used for ___ gram + cocci and _____ gram - bacilli
aerobic; anaerobic
Clindamycin is effective in treating lung abscesses and aspiration pneumonia caused by _____ and _____
bacteroides, fusobacterium
Clindamycin is/is not effective against MRSA
is effective
Clindamycin adminstered IV with _____ and _____ is used to treat AIDS patients with encephalitis caused by _____
pryimethamine, leucovorin;
Toxoplasma gondii
Clindamycin is extensively metbaolized by ____ enzymes in the liver to _____ metabolites
CYP450;
inactive
Side effects of clindamycin:
_____ ______ and _____ _____caused by C. Diff overgrowth, fever, and rash
Psuedomembranous Colitis, toxic megacolon
Tetracyclines form stable ____ with ____ metal ions such as Ca, Al, Cu, and Mg
chelates; polyvalent
The chelates made by tetracyclines and polyvalent metals are soluble/insoluble
insoluble
Things to avoid when taking tetracyclines (3):
Calcium rich food
antacids
hematinics
Tetracyclines chelate calcium during formation of ____. This turns them a ____ color, which becomes worse over time due to _____
teeth; brown/gray;
photo-oxidation
Tetracyclines should be administered via injection with ___ and buffered to an ____ pH to decrease pain caused by the insoluble chelates
EDTA; acidic
The epimer form of tetracycline, ______ is ______
epitetracycline; inactive
The ___ carbon has a ____ group; it has an antiperiplanar relationship with the adjacent carbon’s proton, setting it up for elimination
C6; hydroxyl
The metabolite formed via dehydration of tetracycline is _____. It is inactive and ____.
4-epianhydrotetracycline;
toxic
4-epianhydrotetracycline can cause fatal ____ syndrome, which is due to decreased re-absorption in the _____
fanconi; PCT
____ and ____ are tetracyclines with no C6 ___ group and thus cannot form the toxic metabolite
Minocycline; Doxycycline; OH
Mechanism of action via tetracyclines:
Bind the ____ ribosome, blocking attachment of the tRNA to the ____ site, preventing _____
30S; A; translation
Specifically, tetracyclines inhibit the ______ interaction
codon/anti-codon
The most common use of Tetra- is for ____. They also remain the treatment of choice for infections caused by ____ and ____ due to their intracellular accumulation
acne; chlamydia, Rickettsia
Tetracyclines treat infections caused from the “Great outdoors” (aka zoonotics), such as :
Lyme disease** brucellosis** Plauge Tularemia Q-fever
Demeclocycline has a secondary ___ group at the C6 instead of the tertiary hydroxyl group. Its most stable intermediate is the ___ cation intermediate
hydroxyl
tertiary
Minocycline has no _____ OH group; and therefore no toxic metabolites. It has especially high ___ bioavailability
C6;
oral
Notably, ____ has vestibular toxicities such as vertigo and nausea
minocycline
____ is used as prophylaxis for gum disease
minocycline
_____ is the most hydrophillic tetracycline and used used along with _____ in eye drops
Oxytetracycline;
polymyxin B sulfate
Doxycycline has a ____ half-life relative to the other tetracyclines
long; permits once a day dosing
Chloramphenicol:
Binds the ____ ribosomal subunit, inhibiting _____ _____ activity
50s; peptidyl transferase
Chloramphenicol blocks peptide formation between the ___ and ___ site
P , A
Chloramphenicol is usually administered as chloramphenicol ____ _____, which is ____ in the liver
sodium succinate; hydrolyzed
Resistance to chloramphenicol:
- ____ membrane permeability
- mutation of the _____
reduced; 50s ribosome
Resistance to chloramphenicol:
Elaboration of chloramphenicol ________, which ______ one or both OH groups, forming non-reactive metabolites
acyltransferase
acylates
_____ anemia is a rare but serious side effect of chloramphenicol. More common is _____ anemia, which occurs predictably at a cumulative dose of ___
aplastic;
reversible; 20
Babies don’t have mature ______. Thus, chloramphenicol can cause _____ in infants
glucuronyl transferase;
gray baby syndrome
