Antibiotics: Protein synthesis inhibitors

Question 1

What is the MOA of aminoglycosides and oxazolidinones?

Answer 1

Inhibit formation of initiation complex by interfering w codon at P-site
- 30S for aminoglycosides

Question 2

What is the MOA of tetracyclines?

Answer 2

Block attachment of aminoacyl-tRNA to acceptor site (A-site)
- Reversible bind to 30S subunit and is bacteriostatic

Question 3

What is the MOA of chloramphenicol?

Answer 3

Inhibit activity of peptidlyl-transferase

Question 4

What is the MOA of macrolides and clindamycin?

Answer 4

Inhibit translocation of peptidyl-tRNA from acceptor to donor site
- Bind to 50S and are both bacteriostatic

Question 5

What drugs are aminoglycosides?

Answer 5

Gentamicin, tobramycin, and amikacin

Question 6

What are indications for gentamicin, tobramycin, and amikacin?

Answer 6

Gram negative aerobes but if combined w cell wall synthesis inhibitors can cover gram positive as well

Question 7

What are side effects seen in aminoglycosides?

Answer 7

1. Nephrotoxic
2. Ototoxic
3. Neuromuscular damage which could lead to respiratory paralysis in high doses

Question 8

What are CIs w aminoglycosides?

Answer 8

Renal disease, hearing impairment, and pregnancy

Question 9

What drugs are oxazolidinones?

Answer 9

Linezolid and tedizolid

Question 10

T/F: aminoglycosides are bacteriostatic while oxazolidinones are bacteriocidal

Answer 10

False, aminoglycosides are bacteriocidal while oxazolidinones are bacteriostatic

Question 11

What are indications for linezolid and tedizolid?

Answer 11

Gram positive bacteria and reserved for treatment of infections caused by VRSA, VRE, and MRSA

Question 12

What are side effects of oxazolidinones?

Answer 12

1. GI distress
2. Bone marrow suppression (esp thrombocytopenia)
3. Optic and peripheral neuropathy (long term)
   - Note that linezolid can cause serotonin syndrome and do not use w MAO-I

Question 13

What drugs are tetracyclines?

Answer 13

Doxycycline, tetracycline, minocycline, and tigecycline

Question 14

What are indications for tetracyclines?

Answer 14

Wide variety of gram-positives and gram-negative aerobes and anerobes
(+)= propionebacterium acnes
(-)= brucella
Others= mycoplasma pneumoniae, chlamydia, pneumonia, rickettsial, spirochetes like borrelia (lymes) and treponema pallidum (syphilis)

Question 15

What are adverse effects for tetracyclines?

Answer 15

1. GI distress (n/v/d)
2. Tooth enamel dysplasia and irregularities in bone growth
3. Phototoxicity
   - space out antacids and vitamins w this and CI in pregnancy or children

Question 16

What are special indications for tigecycline?

Answer 16

Used to cover VRE, MRSA, maybe VRSA

Question 17

What drugs are macrolides?

Answer 17

Azithromycin, erythromycin, and clarithromycin

Question 18

What are indications for macrolides?

Answer 18

(+)= streptococcus pneumoniae
(-)= campylobacter jejuni (diarrhea)
- Others include pathogens causing atypical pneumonia like legionella, clamydia, pneumonia, and mycoplasma pneumonia. Also used in mycobacterium avium

“LegMAC”

Question 19

What are side effects for macrolides?

Answer 19

1. GI distress (erythromycin used for gastroparesis)
2. Hepatotoxicity
3. QT prolongation
   - Macrolides inhibit CYP3A4 and PGP except azithromycin

Question 20

What are indications for clindamycin?

Answer 20

Narrow but affects gram-positive and anerobes (above the diaphragm and C diff)
- Used in combination with other antibiotics to provide coverage of anaerobes

Question 21

What are side effects for clindamycin?

Answer 21

GI distress like N/V/D and can cause pseudomembranous colitis from C diff