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81 Cards in this Set
- Front
- Back
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What drugs work on the 30S subunit?
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Aminoglycosides
Tetracyclines Spectinomycin |
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What drugs work on the 50S subunit?
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Everything else:
- Chloramphenicol - Macrolides - Lincosamides (clindamycin) - Telithromycin - Quinupristin/Dalfopristin - Linezolid |
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-thromycin =
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Macrolide
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What are the 4 main events in Bacterial Protein synthesis?
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1.) Formation if Initiation Complex
2.) AA incorporation 3.) Formation of peptide bond 4.) Translocation |
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MOA of Clindamycin and Protein synthesis event it affects
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*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 |
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MOA and P-synthesis event involved with MACROLIDES, TELITHROMYCIN, and CLINDAMYCIN
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*Translocation*
(-static) Block transpeptidation and inhibit translocation of peptidyl-tRNA from acceptor to donor 50S |
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MOA and P-synthesis event involved with TETRACYCLINES
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*Amino acid Incorporation*
(-static) Prevent binding of aminoacyl-charged tRNA to the acceptor site of the ribosome mRNA complex 30S |
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MOA and P-synthesis event involved with STREPTOGRAMINS
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(-cidal)
- Inhibits tRNA synthetase activity - Constrict the exit channel on the ribosome where nascent polypeptides are extruded. 50S |
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MOA and P-synthesis event involved with LINEZOLID
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*Formation of initation complex*
(-static) blockes form'n of the tRNA-ribosome-mRNA ternanry complex 50S |
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Which drug doesn't bind to 80S rRNA, but CAN inhibit hte fxn of mitochondrial ribosomes with 70S rRNA?
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Chloramphenicol
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What structures does Chloramphenicl cross?
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Placenta
BBB Good tissue distribution "-phen" = phenyl group! = LIPID soluble! |
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What hepatic enzyme inactivates most of Chloramphenicol?
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hepatic glucuronosyltransferase
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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 |
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What causes Gray baby syndrome?
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Chloramphenicol
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What causes dose-dependent bone marrow suppression?
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Chloriamphenicol
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What is the spectrum of chloramphenicol's action?
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*Wide spectrum (-static)*
(-cidal against) Works really good against H.INFLUENZAE, N,mengitidis, and bacteroides. |
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Choramphenicol is NOT active against which bug?
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Chlamydia sp.
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Clinical uses for Chloramphenicol
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Wide-spectrum
+ Rickettsia H. influenzae - esp. in neonatal meningitis Neisseria meningitidis Bacteroides But not used often b/c of serious side effects |
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Chloramphenicol is a back up drug for what?
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Severe SALMONELLA sp.
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How does resistance to chloramphenicol develop?
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bacteria make acetyltransferase which inactivates the drug
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Does Chloramphenicol inhibit p450?
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YES!
It increases the elimination t1/5 of phenytoin, tolbutamine, and warfarin |
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What are the main adverse effects of chloramphenicol?
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Gray Baby syndrome
Bone marrow suppression Aplastic anemia (rare but fatal) Hemolytic Anemia in G6PD deficient pts. |
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What characterizes Gray baby syndrome?
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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* |
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Where do Tetracyclines bind?
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30S subunit at the acceptor site
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What is the spectrum of tetracyclines?
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"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 |
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What is the DOC for infectious prostatitis?
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Doxycycline
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Describe the solubility of doxycycline and minocycline
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Doxy = lipid soluble
Mino = water soluble |
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Which tetracycline is used in SIADH?
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Demeclocycline
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Which tetracycline causes diabetes insipidus?
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Demeclocycline
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How do bugs develop resistance to Tetracyclines?
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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) |
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Which tetracycline is currently an alternative to macrolides in the initial tx of community-acquired pneumonia?
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Doxycycline
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Again, what the the primary species that tetracyclines are used against?
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- Mycoplasma pneumoniae(adults)
- Chlamydia - Rickettsia - Vibrio |
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What's one main difference between Chloramphenicol and Tetracyclines in terms of spectrum
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Chloramphenicol does NOT kill Chlamydia. Tetracyclien DOES
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Which tetracycline is used against GI ulcers cuased by h.pylori?
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Tetracycline
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Which tetracycline is used against Lyme disease?
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Doxy
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Which tetracycline is used in the meningococcal carrier state?
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Minocycline
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Which tetracyclineis used for prevention of malaria and in the tx of amebiasis?
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Doxy
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What is tigecycline derived from? and what is tige's use/spectrum?
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From minocycline
- bugs resistant to tetracyclines - gpc resistant to methicillin and vanc: (MRSA & VRE) - B-lactamase producing gnb - anaerobes - chlamydia - mycobacteria |
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How to foods and multivalent cations affect tetracycline absorption?
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they decrease its absorption
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What should you avoid when taking tetracycline?
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Food, dairy, vitamins
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Can tetracyclines be given to babies or pregnant women?
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NO it will cause teeth enamel dysplasia (irreversible) and bone growth irregularities
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What drugs cause cause phototoxicity?
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Tetracyclines (demeclocycline)
Sulfonamides Quinolones |
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What are ALL side effects are seen in tetracyclines?
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- 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 |
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Which tetracyclines cause dizziness and vertigo?
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doxy and minocycline
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List of Macrolides
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Erythromycin (prototype)
Azithromycin Clarithromycin |
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Describe the structure of macrolides
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Macro- so LARGE cyclic LACTONE ring with attached sugars
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Which Macrolide availability is impeded by FOOD?
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AZITHRO
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How is Azithro's distribution in the body unique?
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When districuted througout the body, it is in HIGHER levels in the TISSUES and PHAGOCYTES than in the plasma
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Elimination of erythromycin =
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biliary
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Elimination of clarithromycin =
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urinary
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Elimination of Azithromycin =
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slowly by urine
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Spectrum of activity of Erythromycin
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Campylobacter
Chlamydia Mycoplasma Legionella gpc some gn's |
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What is erythromycin CLASSICALLY associated wiht on boards?
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Legionella pneumonia
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Spectrum of Azithromycin and Clarithromycin
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Similar as erythro-, but INCREASD activity against:
- Chlamydia - MAC!! (M.avium complex) - Toxoplasma |
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Which macrolides inhibit p450?
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erythromycin, clarithromycin
Azithro does NOT inhib. p450 |
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Which macrolide is safe in pregnancy?
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Azithro!
erythro and clarithro are UNSAFE in pregnancy |
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Mechanisms of resistance against macrolides in gp's
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- Efflux pumps
- METHYLASE that adds a methyl group to the ribosomal binding site - Drug-metaboloizing esterases (enterobateriaceae) |
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Methylase-producing microbial strains that are resistant to macrolides, are also cross-resistant to what other drugs?
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Clindamycine and streptogramins
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Recap: which tetracycline is active against MRSA and VRE?
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tigecycline!
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Spectrum of action for Clarithromycin
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Same as erythro
+ - prophylaxis for M avium complex! - H. pylori ulcers! |
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What causes GI irritation wiht the use of macrolides?
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they stimulate MOTOLIN
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Which macrolide has the LEAST amt of GI side effect?
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clarithromycin
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Side effects of Macrolides in general
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- GI irritation
- eosinophilia - reversible deafness at high doses |
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Side effects of erythromycin
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*b/c of erythromycin estolate*
- Acute cholestatic hepatitis (hypersensitivity-based) - Increased risk for Hepatitis in children - Cholestasis |
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Where does Clindamycin distribute well to, and what can it be implicated for?
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Distributes well to bone, and is used for osteomyelitis
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Clindamycin is used as back up for -
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gpc
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Clindamycin is used in prophylaxis of -
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Endocarditis in valvular disease patients who are ALLERGIC to PCN.
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How is Clindamycin implicated in AIDS patients?
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Its used against P. JIROVECI
& in combo w/ PYTIMETHAMINE for AIDS related TOXOPLASMOSIS |
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What is the main bug associated with osteomyelitis?
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Staph. aureus
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Clindamycin was the first known drug (and now, not the only one) to cause
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pseudomembranous colitis
from a superinfection of C. difficile |
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MOA of linezolid
How is it different from Aminoglycosides? |
Inhibits form'n of initiation complex
Works from the 50S side instead of 30S (AG) |
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Spectrum of use for Linezolid
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1.) Drug-resistant gpc: MRSA, PRSP, VRSA, VRE
2.) L. monocytogenes & corynebacterium |
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Linezolid should be reserved for tx of
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infections caused by multidrug-resistant gpb
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Side effects of Linezolid
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Thrombocytopenia and neutropenia (bone marrow suppression) in immunocompromised pts.
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Telithromycin's usage and MOA
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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 |
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Side effects of Telithromycin
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severe hepatotoxicity
visual disturbances fainting episodes |
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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?
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Quinupristin-Dalfopristin
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Spectrum/use for Quinupristin-Dalfopristin
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VRSA
MRSA E. faecalis |
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Quinupristin-Dalfopristin side effects
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Arthralgia-myalgia syndrome
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Do streptogramins inhib. P450? If so, what drugs to they effect?
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*Yes - CYP3A4*
Increase plasma levels of: astemizole cisapride cyclosporine diazepam Nonnucleoside reverse transcriptase inhib's WARFARIN. |