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81 Cards in this Set

  • Front
  • Back
What drugs work on the 30S subunit?
Aminoglycosides
Tetracyclines
Spectinomycin
What drugs work on the 50S subunit?
Everything else:
- Chloramphenicol
- Macrolides
- Lincosamides (clindamycin)
- Telithromycin
- Quinupristin/Dalfopristin
- Linezolid
-thromycin =
Macrolide
What are the 4 main events in Bacterial Protein synthesis?
1.) Formation if Initiation Complex
2.) AA incorporation
3.) Formation of peptide bond
4.) Translocation
MOA of Clindamycin and Protein synthesis event it affects
*Formation of peptide bond*
(-static)
Inhibits peptidyl-transferase, thus transpeptidation, blocking the binding of the aa-moitey of the tRNA to the acceptor site on ribosomal mRNA
MOA and P-synthesis event involved with MACROLIDES, TELITHROMYCIN, and CLINDAMYCIN
*Translocation*

(-static)

Block transpeptidation and inhibit translocation of peptidyl-tRNA from acceptor to donor
50S
MOA and P-synthesis event involved with TETRACYCLINES
*Amino acid Incorporation*

(-static)

Prevent binding of aminoacyl-charged tRNA to the acceptor site of the ribosome mRNA complex
30S
MOA and P-synthesis event involved with STREPTOGRAMINS
(-cidal)
- Inhibits tRNA synthetase activity
- Constrict the exit channel on the ribosome where nascent polypeptides are extruded.
50S
MOA and P-synthesis event involved with LINEZOLID
*Formation of initation complex*

(-static)

blockes form'n of the tRNA-ribosome-mRNA ternanry complex
50S
Which drug doesn't bind to 80S rRNA, but CAN inhibit hte fxn of mitochondrial ribosomes with 70S rRNA?
Chloramphenicol
What structures does Chloramphenicl cross?
Placenta
BBB
Good tissue distribution

"-phen" = phenyl group! = LIPID soluble!
What hepatic enzyme inactivates most of Chloramphenicol?
hepatic glucuronosyltransferase
What 2 groups of ppl should you watch out for with Chloramphenicol
(need dose dependent reductions)
Neonates (incomlete maturation of the liver-> toxicity)

Pt's with liver damage/dysfunction
What causes Gray baby syndrome?
Chloramphenicol
What causes dose-dependent bone marrow suppression?
Chloriamphenicol
What is the spectrum of chloramphenicol's action?
*Wide spectrum (-static)*

(-cidal against) Works really good against H.INFLUENZAE, N,mengitidis, and bacteroides.
Choramphenicol is NOT active against which bug?
Chlamydia sp.
Clinical uses for Chloramphenicol
Wide-spectrum
+
Rickettsia
H. influenzae - esp. in neonatal meningitis
Neisseria meningitidis
Bacteroides

But not used often b/c of serious side effects
Chloramphenicol is a back up drug for what?
Severe SALMONELLA sp.
How does resistance to chloramphenicol develop?
bacteria make acetyltransferase which inactivates the drug
Does Chloramphenicol inhibit p450?
YES!

It increases the elimination t1/5 of phenytoin, tolbutamine, and warfarin
What are the main adverse effects of chloramphenicol?
Gray Baby syndrome
Bone marrow suppression
Aplastic anemia (rare but fatal)
Hemolytic Anemia in G6PD deficient pts.
What characterizes Gray baby syndrome?
Decreased RBC's
Cyanosis
Vomiting
Green stools
Vasomotor collapse
*B/c of accumulation of the unmetabolized drug, sicne the neonateal liver is not completely mature*
Where do Tetracyclines bind?
30S subunit at the acceptor site
What is the spectrum of tetracyclines?
"broad spectrum"

Good against chlamydia, mycoplasma, H.pylori, RICKETTSIA, BORRELIA (doxycycline)

What I can hit with a macrolide, I can hit with a tetracycline and vice versa
What is the DOC for infectious prostatitis?
Doxycycline
Describe the solubility of doxycycline and minocycline
Doxy = lipid soluble
Mino = water soluble
Which tetracycline is used in SIADH?
Demeclocycline
Which tetracycline causes diabetes insipidus?
Demeclocycline
How do bugs develop resistance to Tetracyclines?
Efflux pumps
format'n of ribosomal protection proteins that interfere with drug binding

These are not conferred to tigecycline (except Proteus and pseudomonas' efflux pumps)
Which tetracycline is currently an alternative to macrolides in the initial tx of community-acquired pneumonia?
Doxycycline
Again, what the the primary species that tetracyclines are used against?
- Mycoplasma pneumoniae(adults)
- Chlamydia
- Rickettsia
- Vibrio
What's one main difference between Chloramphenicol and Tetracyclines in terms of spectrum
Chloramphenicol does NOT kill Chlamydia. Tetracyclien DOES
Which tetracycline is used against GI ulcers cuased by h.pylori?
Tetracycline
Which tetracycline is used against Lyme disease?
Doxy
Which tetracycline is used in the meningococcal carrier state?
Minocycline
Which tetracyclineis used for prevention of malaria and in the tx of amebiasis?
Doxy
What is tigecycline derived from? and what is tige's use/spectrum?
From minocycline
- bugs resistant to tetracyclines
- gpc resistant to methicillin and vanc: (MRSA & VRE)
- B-lactamase producing gnb
- anaerobes
- chlamydia
- mycobacteria
How to foods and multivalent cations affect tetracycline absorption?
they decrease its absorption
What should you avoid when taking tetracycline?
Food, dairy, vitamins
Can tetracyclines be given to babies or pregnant women?
NO it will cause teeth enamel dysplasia (irreversible) and bone growth irregularities
What drugs cause cause phototoxicity?
Tetracyclines (demeclocycline)
Sulfonamides
Quinolones
What are ALL side effects are seen in tetracyclines?
- Vestibular tox: does-dependent DIZZINESS, and VERTIGO
- Fanconi's syndrome (w/outdated tetra's)
- GI candidiasis, GI disturbances
- Teeth enamel dysplasia
- Irregular bone growth
- Hepatic necrosis
Which tetracyclines cause dizziness and vertigo?
doxy and minocycline
List of Macrolides
Erythromycin (prototype)
Azithromycin
Clarithromycin
Describe the structure of macrolides
Macro- so LARGE cyclic LACTONE ring with attached sugars
Which Macrolide availability is impeded by FOOD?
AZITHRO
How is Azithro's distribution in the body unique?
When districuted througout the body, it is in HIGHER levels in the TISSUES and PHAGOCYTES than in the plasma
Elimination of erythromycin =
biliary
Elimination of clarithromycin =
urinary
Elimination of Azithromycin =
slowly by urine
Spectrum of activity of Erythromycin
Campylobacter
Chlamydia
Mycoplasma
Legionella
gpc
some gn's
What is erythromycin CLASSICALLY associated wiht on boards?
Legionella pneumonia
Spectrum of Azithromycin and Clarithromycin
Similar as erythro-, but INCREASD activity against:
- Chlamydia
- MAC!! (M.avium complex)
- Toxoplasma
Which macrolides inhibit p450?
erythromycin, clarithromycin

Azithro does NOT inhib. p450
Which macrolide is safe in pregnancy?
Azithro!

erythro and clarithro are UNSAFE in pregnancy
Mechanisms of resistance against macrolides in gp's
- Efflux pumps
- METHYLASE that adds a methyl group to the ribosomal binding site
- Drug-metaboloizing esterases (enterobateriaceae)
Methylase-producing microbial strains that are resistant to macrolides, are also cross-resistant to what other drugs?
Clindamycine and streptogramins
Recap: which tetracycline is active against MRSA and VRE?
tigecycline!
Spectrum of action for Clarithromycin
Same as erythro
+
- prophylaxis for M avium complex!
- H. pylori ulcers!
What causes GI irritation wiht the use of macrolides?
they stimulate MOTOLIN
Which macrolide has the LEAST amt of GI side effect?
clarithromycin
Side effects of Macrolides in general
- GI irritation
- eosinophilia
- reversible deafness at high doses
Side effects of erythromycin
*b/c of erythromycin estolate*

- Acute cholestatic hepatitis (hypersensitivity-based)
- Increased risk for Hepatitis in children
- Cholestasis
Where does Clindamycin distribute well to, and what can it be implicated for?
Distributes well to bone, and is used for osteomyelitis
Clindamycin is used as back up for -
gpc
Clindamycin is used in prophylaxis of -
Endocarditis in valvular disease patients who are ALLERGIC to PCN.
How is Clindamycin implicated in AIDS patients?
Its used against P. JIROVECI
&
in combo w/ PYTIMETHAMINE for AIDS related TOXOPLASMOSIS
What is the main bug associated with osteomyelitis?
Staph. aureus
Clindamycin was the first known drug (and now, not the only one) to cause
pseudomembranous colitis

from a superinfection of C. difficile
MOA of linezolid

How is it different from Aminoglycosides?
Inhibits form'n of initiation complex

Works from the 50S side instead of 30S (AG)
Spectrum of use for Linezolid
1.) Drug-resistant gpc: MRSA, PRSP, VRSA, VRE

2.) L. monocytogenes & corynebacterium
Linezolid should be reserved for tx of
infections caused by multidrug-resistant gpb
Side effects of Linezolid
Thrombocytopenia and neutropenia (bone marrow suppression) in immunocompromised pts.
Telithromycin's usage and MOA
Same MOA as macrolides, but is used for macrolide-resistant strains.

Binds tighter to ribosomes and is a poor susbtrate for efflux pumps

Comm.-acquired pneumonia
Side effects of Telithromycin
severe hepatotoxicity

visual disturbances

fainting episodes
What two Streptogramins are combined for a bactericidal effect that binds to 50S, prevents interaction with the acceptor site, stim. its dissociation from ternary complex, and prevents extrusion of completed polypeptide?
Quinupristin-Dalfopristin
Spectrum/use for Quinupristin-Dalfopristin
VRSA
MRSA
E. faecalis
Quinupristin-Dalfopristin side effects
Arthralgia-myalgia syndrome
Do streptogramins inhib. P450? If so, what drugs to they effect?
*Yes - CYP3A4*
Increase plasma levels of:
astemizole
cisapride
cyclosporine
diazepam
Nonnucleoside reverse transcriptase inhib's
WARFARIN.