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Flashcards in Protein Synthesis Inhibitors Deck (32):
1

Classes of antibacterial protein synthesis inhhibtors

-macrolides
-tetracyclines
-aminglycosides
-lincomycins (clindamycin)
-oxazolidinones
-streptogamins
-chloramphenicol

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Macrolides: examples

-erythromycin
-clarithromycin
-azithromycin

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Macrolides: mechanism of action

-blocks protein synthesis
-binds 50S ribosomal subunit and blocks translocation
-bacteriostatic

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Macrolides: pharmocokinetics

-good oral --> can be absorbed in GI tract
-wide distribution except to brain/CSF
-metabolism involves both liver and kidney

5

Macrolides: spectrum/clinical use

-gram+ cocci/rods (strep, staph, pneumococci)
-some gram- cocci
-gram- bacilli (pertussis, H. flu, H. pylori)
-atypical: mycoplasma/chlamydia

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Macrolides: adverse reactions

-GI disturbances
-some drug interactions possible

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Tetracyclines: examples

-tetracycline
-doxycycline
-minocycline

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Tetracyclines: mechanism of action

-protein synthesis inhibitor
-bacteriostatic
-binds 30S ribosome

9

Tetracyclines: pharmacokinetics

-good oral (on empty stomach, impaired by milk)
-excellent tissue penetration
-concentrated in liver, most excreted in urine (except doxy/mino)

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Tetracyclines: spectrum/clinical uses

-broad spectrum agent (many organisms now resistant)
-gram+ cocci (MRSA)
-atypical organisms: chlamydia, mycoplasma
-spirochetes

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Tetracyclines: adverse reaction

-avoid during 2nd half of pregnancy and children < 8yo
-GI disturbance
-yeast infection
-drug interaction w/antacids and iron supplements --> decreased bioavailability

12

Clindamycin: mechanism of action

-inhibit protein synthesis
-binding 50S subunit
-bacteriostatic

13

Clindamycin: pharmacokinetics

-good oral
-penetrates most tissue well, especially bone (not CSF)
-liver metabolism
-excreted in breast milk

14

Clindamycin: spectrum/clinical uses

-treatment of severe anaerobic infections
-narrow spectrum
-gram+ cocci (strep, MSSA osteomyelitis, MRSA cutaneous)
-anaerobes (bacteroides fragilis)

15

Clindamycin: adverse reactions

-pseudomembranous colitis
-severe diarrhea

16

Aminglycosides: examples

-streptomycin
-tobramycin
-gentamicin

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Aminglycosides: mechanism of action

-protein synthesis inhibitor
-bactericidal
-inhibits protein synthesis initiation

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Aminglycosides: pharmacokinetics

-poor oral, good IV or IM
-distributes only to ECF
-renal excretion

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Aminglycosides: spectrum/clinical uses

-limited by toxicity
-narrow spectrum
-gram- bacilli aerobes (pseudomonoas, E. coli)

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Aminglycosides: adverse reactions

-very toxic
-eighth nerve damage (auditory, vestibular)
-reversible renal toxicity
-drug-drug interactions w/B-lactams (enhance) and penicilinns (inhibit)

21

Chloramphenicol: mechanism of actions

-inhibit protein synthesis
-binding to 50S ribosome
-mostly bacteriostatic

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Chloramphenicol: pharmacokinetics

-good oral
-widely distributed, including CNS/CSF
-liver metabolism
-excreted in breast milk

23

Chloramphenicol: spectrum/clinical uses

-broad spectrum (limited by toxicity)
-gram+/- cocci (N. meningitis)
-gram- bacilli (H. flu, salmonella typhi=typhoid fever)
-anaerobes (bacteroides)
-atypical organisms (rickettsia)

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Chloramphenicol: adverse reactions

-bone marrow toxicity
-gray baby syndrome
-GI disturbances

25

Oxazolidinone (Linezolid): mechanism of action

-novel protein synthesis inhibitor
-bacteriostatic
-binds 50S ribosome

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Oxazolidinone (Linezolid): pharmacokinetics

-good oral (IV available)
-readily distributed to well-perfused tissue
-nonenzymatic metabolism; some renal excretion

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Oxazolidinone (Linezolid): spectrum/clinical uses

-used for life-threatening infections
-gram+ cocci: enterococci (+VRE), staphylococci (+MRSA), streptococci

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Oxazolidinone (Linezolid): adverse reactions

-minor
-inhibits MAO; linezolid+SSRI-->hypertensive response

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Streptogramin (Quinupristin/Dalfopristin): mechanism of action

-protein synthesis inhibitor
-binds 50S ribosome
-bactericidal

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Streptogramin (Quinupristin/Dalfopristin): pharmacokinetics

-IV only
-liver metabolism + biliary excretion (no renal)

31

Streptogramin (Quinupristin/Dalfopristin): spectrum/clinical uses

-used for life-threatening infections
-gram+ cocci: enterococci (+VRE), staphylococci (+MRSA), streptococci

32

Streptogramin (Quinupristin/Dalfopristin): adverse reactions

-infusion site irritation
-inhibits CYP3A4 --> increase plasma levels of drugs metabolized by that enzyme