Pharm - Protein Synth Inhibitors: Tetracyclines and glycylcyclines Flashcards
tetracyclines and glycylcyclines are bacteriostatic or cidal?
static
macrolides are bacteriostatic or cidal?
static
erythromycin is an examples of a……..
macrolide
streptogramins are bacteriostatic or cidal?
cidal (in combo)
cloramphenicol is bacteriostatic or cidal
static
lincosamides are bacteriostatic or cidal
give an ex
clindamycin
static
aminoglycosides are bacteriostatic or cidal
cidal
oxazolidinones are bacteriostatic or cidal
static
most of a bacterial ribosome consists of what?
RNA
aminoglycosides act on what bacterial ribosome
30s
tetracyclines and glycylcyclines act on what bacterial ribosome
30s
____- and _____ are the only protein synthesis inhibitors that act on the 30s ribosome. all the others act on 50s
tetracyclines and glycylcyclines and aminoglycosides
the 50s subunit is the ___ ribsosome
the larger ribosomal subunit
30s is the smol one
name 3 glycylcylines
tigecycline
eravacycline
omadacycline
why were the glycylcyclines made
are long acting (better pharmacokinetic profile) and have a better resistance profile than tetracyclines
how do the glycylcyclines have a better resistance profile than the tetracyclines
their structure doesn’t allow for proper binding to the efflux pump
tetracyclines are _____ spectrum ____ antibiotics that inhibit what?
broad spectrum bacteriostatic that inhibit protein synthesis
briefly explain the MOA of tetracyclines
they reversibly bind to the 30s subunit of the bacterial ribosome
this blocks the binding ot the aminoacyl-tRNA to the acceptor (A) site on the mRNA-ribosome complex
what is the aminoacyl-tRNA
the tRNA that brings the amino acid
how do tetracyclines enter the bacteria
by passive diffusion and in part by active transport (energy dependent)
true or false
tetracyclines are only active against gram negative bacteria
FALSE - broad spectrum
gram (+) and (-)
what are tetracyclines NOT very active against
pseudomonas, neisseria, enterobacter
3 methods of tetracycline resistance
- decreased influx of the AB OR getting an efflux pathway
- bacteria produce a protein that protects the ribosome - displaces the tetracycline from its 30s target
- enzymatically inactivated
name 3 different efllux pumps that bacteria can produce against tetracyclines
include what bacteria produce them and what they provide resistance to
Tet (AE) efflux pump - produced by gram negative species. provides resistance against tet,doxy, and mino - BUT NOT TIGECYCLINE
Tet (K) efflux pump - produced by staphylococci. provides resistance to tetracycline but NOT doxy, mino, or tigecycline
proteus and pseudomonas produce their own specific efflux pump that gives resistance to ALLL - tetracyclines and tigecycline
as mentioned, a mechanism of resistance to tetracyclines is the production of a ribosomal protection protein
name 2 of these proteins and what they are/aren’t resistant to
tet(M) and tet(O)
resistant to doxy, tet, and mino, BUT STILL SUSCEPTIBLE TO TIGECYCLINE
therefore, tigecycline overcomes 2 resistance mechanisms
what other antibiotic class has a similar resistance mechanism of protection proteins
fluoroquinolones — QNR proteins
how can the absorption of tetracyclines be impaired
when given with divalent and trivalent cations (like quinolones)
do not give dairy products or antacids
the oral absorption of most tetracyclines is……
incomplete
how is tigecycline administered
NOT ABSORBED WELL – only parenteral
concern with tetracyclines
-cross placenta and excreted in breast milk
-cause damage to growing bones and teeth!!!
explain the DDIs of tetracyclines
there are a lot. many drugs like carbamezepime, phenytoim, barbiturates, and alcohol decrease the half life by 50% — so need to increase dose
______ is a substrate of CYP3A4, so there are many potential drug-drug interactions
eravacycline
true or false
tetracyclines have good activity against anaerobes
true
(how to remember - they’re used in acne)
name 5 things in which tetracyclines are drug of choice
rickettsia
borrelia
mycoplasma pneumonia
chlamydia
some spirochetes
true or false
tetracyclines can be used for CAP
true
can tetracyclines be used for MRSA
mild-moderate MRSA
true or false
tetracyclines can’t be used in lyme disease
false - they can
true or false
tigecycline is broad spectrum bacteriostatic
true
high potency against range of both gram (+) and (-)
TRUE OR FALSE
tigecycline is not active against MRSA
false - it is
how is tigecycline administered and how eliminated
IV only
eliminated through bile - no dose adjustment for renal insufficiency!
eravacycline is a _________ tetracycline for _______
fluorinated
complicated intrabdominal infections
main adverse affects of all tetracyclines
GI -NVD(because broad)
photosensitivity
hepatoxicity
nephrotoxicity
discolor teeth and affect bone growth
FANCONI SYNDROME (only for expired) — sugars and electrolytes not reabsorbed back into the body
can tetracyclines be used in pregnancy
NO - teratogenic
true or false
production of Tet(M) protein is a resistance mechanism against tigecycline
FALSE — tigecycline is resistant to this mechanism
chemically, what is tigecycline
a glycylcycline
what does the extended structure of tigecycline allow for
resistance doesn’t happen as much as tetracyclines
true or false
tigecycline is active against MRSA
true
