Protein Synthesis Inhibitors

Question 1

What are the purposes of the protein synthesis inhibitors?

Answer 1

These inhibitors specifically target smaller bacterial ribosome (70S, made of 30S and 50S), leaving human ribosome (80S) unaffected
Buy AT 30m CCEL at 50
(30S) 
Aminoglycosides (bactericidal)
Tetracyclines        (bacteriostatic)  

(50S)
Chloramphenicol, Clindamycin (bacteriostatic)
Erythromycin (macrolides) (bacteriostatic)
Linezolid (variable)

Question 2

What are the aminoglycosides?

Answer 2

Gentamicin
Neomycin
Amikacin
Tobramycin
Streptomycin

Question 3

What is the mechanism of the aminoglycosides?

Answer 3

Bactericidal; inhibit formation of initiation complex and cause misreading of mRNA. Also block translocation. Require 02 for uptake; therefore ineffective against anaerobes.

Question 4

What toxicities should we look for with aminoglycosides?

Answer 4

Nephrotoxicity
Neuromuscular blockade
Ototoxicity
Teratogen

Question 5

What are the tetracyclines?

Answer 5

Tetracycline
Doxycycline
Demeclocycline
Minocycline

Question 6

What is the mechanism of the tetracyclines?

Answer 6

Bacteriostatic; bind to 30S and prevent attachment of aminoacyl-tRNA; limited CNS penetration. Doxycycline is fecally eliminated can can be used in patients with renal failure. Do not take with milk, antacids, or iron-containing preparations because divalent cations inhibit its absorption in the gut.

Question 7

What are the uses of the tetracyclines?

Answer 7

Borrelia burgdorferi
M. pneumoniae
Rickettsia
Chlamydia

Question 8

What toxicities should we look for with tetracyclines?

Answer 8

GI distress
Discoloration of teeth and inhibition of bone growth in children
Photosensitivity
Contraindicated in pregnancy

Question 9

What are the macrocodes?

Answer 9

Azithromycin
Clarithromycin
Erythromycin

Question 10

What is the mechanism of the macrolides?

Answer 10

Inhibit protein synthesis by blocking translocation (macroslides); bind to the 23S rRNA of the 50S ribosomal subunit. Bacteriostatic

Question 11

What are the uses of macrolides?

Answer 11

Atypical pneumonias and gram positive cocci

Question 12

What toxicities should we look for with the macrolides?

Answer 12

MACRO
Motility issues
Arrythmia caused by prolonged QT
Acute Cholestatic hepatitis
Rash
eOsinophilia
Increases the serum concentration of theophyllines, oral anticoagulants

Question 13

What is the mechanism of Chloramphenicol?

Answer 13

Blocks peptidyltransferase at 50S ribosomal subunit. Bacteriostatic.

Question 14

What are the uses of Chloramphenicol?

Answer 14

Meningitis (H. influenzae, N. meningitidis, S. pneumoniae)

Question 15

What are the toxicities of Chloramphenicol?

Answer 15

Anemia (dose dependent), aplastic anemia, gray baby syndrome - infants lack UDP glucuronyl transferase.

Question 16

What is the mechanism of Clindamycin?

Answer 16

Blocks peptide transfer (transpeptidation) at 50S ribosomal subunit. Bacteriostatic.

Question 17

What are the uses of Clindamycin?

Answer 17

Anaerobic infections in aspiration pneumonia or lung abscesses. Also oral infections with mouth anaerobes.

Question 18

What toxicities should we look for with Clindamycin?

Answer 18

Pseudomembranous colitis
fever
diarrhea