Protein Synthesis Inhibitors Flashcards
(49 cards)
30S Inhibitors:
Aminoglycosides (bactericidal)
Tetracyclines (bacteriostatic)
50S Inhibitors:
Chloramphenicol, Clindamycin (bacteriostatic)
Erythromycin (macrolides) (bacteriostatic)
Linezolid (variable)
Oxazolidinones:
Linezolid
Linezolid: mech
Inhibit protein synthesis by binding to 50S subunit and preventing formation of the initiation complex.
Linezolid: uses
Gram+ species including MRSA and VRE
Linezolid: tox
Bone marrow suppression (especially thrombocytopenia), peripheral neuropathy, serotonin syndrome
Linezolid: MOR
point mutation in ribosomal RNA
Aminoglycosides:
Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin
“Mean” (aMINoglycoside) GNATS caNNOT kill anaerobes
Aminoglycosides: mech
Bactericidal
Inhibit formation of initiation complex and cause misreading of mRNA. Also block translocation. Require O2 for uptake; therefore ineffective against anaerobes.
“A initiates the Alphabet”
Aminoglycosides: uses
Severe gram - rod infections. Synergistic with beta-lactam antibiotics.
Neomycin for bowel surgery
Aminoglycosides: tox
Nephrotoxicity (especially when used with cephalosporins), Neuromuscular blockade, Ototoxicity (especially when used with loop diuretics). Teratogen.
Streptomycin - worst for ototoxicity
Aminoglyclosides: MOR
Bacterial transferase enzymes inactivate the drug by acetylation, phosphorylation, or adenylation.
Amikacin is more resistant, so broadest spectrum.
Tetracyclines:
Tetracycline, Doxycycline, Minocycline, Tigecycline
Tetracyclines: mech
Bacteriostatic
Binds 30S and prevents attachment of aminoacyl-tRNA; limited CNS penetration.
Doxycycline is fecally eliminated and can be used in patients with renal failure. Do not take with milk (Ca2+), antacids (Ca2+ or Mg2+), or iron-containing preparations because divalent cations inhibit its absorption in the gut.
Tetracyclines: uses
Borrelia burgdorferi (DOC), M. pneumoniae. Drug’s ability to accumulate intracellularly makes it very effective against Rickettsia and Chlamydia. Also used to treat acne.
Tetracyclines: tox
GI distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity.
Contraindicated in pregnancy (cross placenta and found in breast milk)
Outdated Tetracyclines –> Fanconi syndrome
Tetracyclines: MOR
decreased uptake or increased efflux out of bacterial cells by plasmid-encoded transport pumps
Macrolides:
Azithromycin, Clarithromycin, Erythromycin
Macrolides: mech
Inhibit protein synthesis by blocking translocation (“macroslides”); bind to the 23S rRNA of the 50 S ribosomal subunit. Bacteriostatic.
Macrolides: uses
Atypical pneumonias (Mycoplasma, Chlamydia, Legionella), STDs (for Chlamydia), and gram + cocci (streptococcal infections in patients allergic to penicillin). Corynebacteria Tx and Px of Bordetella Pertussis
Macrolides: MOR
Methylation of 23S rRNA-binding site prevents binding of drug.
Chloramphenicol: mech
Blocks peptidyltransferase at 50S ribosomal subunit. Blocks peptide bond formation.
Bacteriostatic
Chloramphenicol: uses
Meningitis (Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae) and Rocky Mountain Spotted Fever (Rickettsia rickettsii).
Limited use owing to toxicities but often still used in developing countries because of low cost.
Chloramphenicol: tox
Anemia (dose dependent), aplastic anemia (dose dependent), gray baby syndrome (in premature infants because they lack the liver UDP-glucuronyl transferase)