Protein synthesis inhibitors Flashcards by Ben Harris

Q

Name oxazolidinones

A

Linezolid

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Q

Mechanism of linezolid

A

Bacteriostatic

Binds 50S subunit and prevents formation of initiation complex

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Q

Spectrum of linezolid

A

Gram+, MRSA, Vanco-resistant enterococci

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Q

Side effects of linezolid

A

Bone marrow suppression, inhibits monoamine oxidase leading to serotonin syndrome (Don’t treat w/ SSRI)

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Q

Resistance to linezolid

A

Alteration of 23S rRNA of 50S subunit to prevent binding

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Q

Name Aminoglycosides

A

Gentamicin, Amikacin, Tobramycin

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Q

Mechanism of Aminoglycosides

Gentamicin, Amikacin, Tobramycin

A

Bactericidal, prevents formation of initiation complex, causes misreading of mRNA, induces early termination

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Q

Spectrum of Aminoglycosides

Gentamicin, Amikacin, Tobramycin

A

Extended spectrum

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Q

Side effects of Aminoglycosides

Gentamicin, Amikacin, Tobramycin

A

Tubular necrosis: ototoxicity and nephrotoxicity

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Q

Resistance to Aminoglycosides

Gentamicin, Amikacin, Tobramycin

A

Intrinsic: failure of antibiotic to enter cell (needs facilitated transport)
Acquired: acquisition of enzyme to inactivate the drug (amikacin is less suscetible to enzyme)

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Q

Notes on Aminoglycosides

Gentamicin, Amikacin, Tobramycin

A

Poor absorption in GI, usually administered IV, does not cross BBB. REQUIRES ENERGY TO ENTER CELL- TREAT W/ ANTIBIOTIC TO DESTROY CELL MEMBRANE

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Q

Name tetracyclines

A

Tetracyclin, doxycycline, minocycline

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Q

Mechanism of tetracyclines

Tetracyclin, doxycycline, minocycline

A

Bacteriostatic- binds to 30S subunit preventing attachment of aminoacyl-tRNA

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Q

spectrum of tetracyclines

Tetracyclin, doxycycline, minocycline

A

Broad: B. burgdorfei, H. pylori, Mycoplasma, Chlamydia

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Q

Side effects of tetracyclines

Tetracyclin, doxycycline, minocycline

A

Chelates metal ions (Calcium), GI irritation, photosensitivity, discoleration of teet, inhibits bone growth. Don’t prescribe during pregnancy.

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Q

Resistance to tetracyclines

Tetracyclin, doxycycline, minocycline

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A

Increased efflux, ribosomal protection proteins protect A site from drug

Q

Notes on tetracyclines

Tetracyclin, doxycycline, minocycline

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A

don’t treat during pregnancy

Q

Mechanism of Chloramphenicol

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A

Bacteriostatic- binds 50S preventing peptide bond formation- kills peptidyltransferase reaction

Q

Spectrum of Chloramphenicol

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A

Extended spectrum- but limited due to toxicity

Q

Chloramphenicol side effects

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A

Toxic, bone marrow depression, aplastic anemia, grey baby syndrome

Q

Resistance to chloramphenicol

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A

Reduces membrane permeability, acetyltransferase modifies drug

Q

Notes on chloramphenicol

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A

don’t use on newborn babies because of immature liver- high likelihood of toxicity

Q

Name macrolides

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A

erythromycin, azithromycin, clarithromycin

Q

Macrolide mechanism

erythromycin, azithromycin, clarithromycin

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A

Bacteriostatic- inhibits translocation by binding to 23S rRNA of 50S subunit

Macrolide spectrum | erythromycin, azithromycin, clarithromycin

Broad- coverage of respiratory pathogens, pharyngitis, pneumonia, otitis media, Chlamydia (single dose)

Macrolide side effects | erythromycin, azithromycin, clarithromycin

GI discomfort, inhibitor of CYP3A4 (except azithromycin), Clarithromycin not safe during pregnancy, Azithro can cause pyloric stenosis in infants

Resistance to macrolides | erythromycin, azithromycin, clarithromycin

Methylation of 23S rRNA site, increased efflux, hydrolysis of macrolides by esterases

Name lincosamide

Clindamycin

Clindamycin mechanism

Bacteriostatic- blocks translocation of 50S ribosomal subunit

Clindamycin spectrum

Gram+, including anaerobic bacteria, skin and soft tissue infections, Acne vulgaris

Clindamycin side effects

Diarrhea, abdominal pain, mucus and blood in stool, superinfection with C. diff

Resistance to clindamycin

Mutation in ribosome methylation of rRNA, cross resistance to macrolides and streptogrammins, enzymes can inactivate the drug

Name Streptogrammins

Quinipristin, Dalfopristin

Streptogrammins mechanism | Quinipristin, Dalfopristin

Combined bactericidal for some organisms, bind 50S to inhibit translocation

Streptogrammins spectrum | Quinipristin, Dalfopristin

Multiple drug-resistant Gram+

Streptogrammins side effects | Quinipristin, Dalfopristin

High incidence of arthalgias, inhibits CYP3A4 and likely has significant drug interactions

Resistance to streptogrammins | Quinipristin, Dalfopristin

Ribosomal methylase inhibits binding of drug, Enzymes inactivate drug, efflux, cross resistance with macrocodes and clindamycin

Notes on streptogrammins | Quinipristin, Dalfopristin

Always treat together.