protein synthesis blockers

Question 0

Macrolides

Azithromycin, clarithromycin, erythromycin

Answer 0

• Mech: 50S prevent translocation.
• Uses: atypical pneumonias (mycoplasma, chlamydia, LEGIONELLA) and G+ cocci.
• Tox: P450 inhibitor (except azithromycin).

Question 1

Tetracyclins

Tetracyclin, doxycycline, minocycline

Answer 1

• Mech: BS, 30S (only ones to bind to 30S) prevent elongation by preventing binding of loaded tRNA.
• Use: Borrelia burgdorferi (Lyme disease), chlamydiae, mycoplasma, rikettsiae, spirochetes, H.pylori. Treatment of acne.
• PK: CHELATOR, discolor teeth, inhibit bone growth, photosensitivity. CI in pregnancy

Question 2

Clindamycin

Answer 2

• Mech: 50S, prevent translocation
• Uses: Anaerobes (bacteroides, clostridium perfringens) in aspiration pneumonia, lung abscesses, oral infections, and group A strep.
• Tox: C. dif overgrowth causing pseudomembranous colitis.

Question 3

Streptogramins

quinupristin-dalfopristin

Answer 3

• Mech: 50S BC
• Uses: staph, VRE
• PK: renal clearance
• Tox: P450 inhibition, arthalgia, myalgia.

Question 4

Chloramphenicol

Answer 4

• Mech: 50S blocks peptidyltransferase
• Uses: Meningitis (h. influenzae, neiseeria meningitidis, strep. pneumo) and Rocky Mountain spotted fever (rickettsia rickettsii). Used outside U.S. for bacillary dysentery.
• PK: short half life
• Tox: dose-related anemia, gray-baby syndrome.

Question 5

Oxazolidinone

linezolid

Answer 5

• Mech: 23S of 50S, BS
• Use: MRSA, VRE, PRSP
• PK: hepatic clearance
• Tox: dose-related anemia, neuropathy, serotonin syndrome w/SSRIs