Protein Synthesis Inhibitors

Question 1

MOA of erythromycin

Answer 1

Inhibit protein synthesis via binding to the 23S and 50S ribosomal subunits

Question 2

Bug coverage of erythromycin

Answer 2

Atypicals
H. influ
M. cat
Strep
Staph
C diff

Question 3

Examples of macrolides/azalides

Answer 3

Azithromycin
Clarithromycin

Question 4

Bug coverage of macrolides/azalides

Answer 4

Atypicals
H. influ
M. cat
Chlamydia trachomatis

Question 5

Clinical uses of macrolides

Answer 5

Respiratory tract
Chlamydia
PUD
MAI

Question 6

Adverse effects of macrolides

Answer 6

Erythro&raquo_space; azith/clarith
GI upset
Thrombophlebitis
Cholestatic hepatits
QT prolongation
CV death

Question 7

Important drug interactions of macrolides/azalides

Answer 7

**CYP450 inhibition!!
- midazolam, cyclosporine, tacrolimus, statins, non DHP, digoxin, warfarin, phenytoin

Question 8

MOA of clindamycin

Answer 8

Inhibits protein synthesis by binding to the 50S subunit

Question 9

Bug coverage of clindamycin

Answer 9

Gram positive anaerobes
Gram negative anaerobes
GAS
GBS
VGS
MSSA
MRSA

Question 10

Adverse effects of clindamycin

Answer 10

Diarrhea
Allergy/anaphylaxis
**C diff infection

Question 11

MOA of tetracyclines

Answer 11

Inhibit protein synthesis by binding to the 30S subunit

Question 12

Bug coverage of tetracyclines

Answer 12

Atypicals
Intracellular pathogens
MSSA
MRSA
Strep

Question 13

Examples of tetracyclines

Answer 13

Tetracycline
Minocycline
Doxycycline

Question 14

Adverse events of tetracyclines

Answer 14

Photosensitivity
Skin discoloration
Dizziness/vertigo
Permanent discoloration of teeth
– avoid in pregnancy, children < 8 yo
GI irritation – take with water while standing

Question 15

Pertinent tetracycline drug interactions

Answer 15

Chelation with cations
increased digoxin concentrations
increased warfarin effect
decreased effectiveness of oral contraceptives

Question 16

Bug coverage of tigecycline

Answer 16

All but bacillus, listeria, TB

Question 17

Adverse effects of tigecycline

Answer 17

GI upset – children and women < 50 yo NOT 5HT related
Diarrhea – NOT C diff related

Question 18

MOA of linezolid

Answer 18

Inhibits protein synthesis by binding to the 50S subunit of the ribosome

Question 19

Bug coverage of Linezolid

Answer 19

MSSA
MRSA
Strep
VSE
VRE
Atypicals
TB

Question 20

Adverse events of linezolid

Answer 20

Thrombocytopenia
Peripheral neuropathy
Optic neuritis

Question 21

Important drug interaction of linezolid

Answer 21

Inhibits MAO = risk serotonin syndrome
Inpatient – monitor
Outpatient – alternative abx

Question 22

MOA of aminoglycosides

Answer 22

Inhibit protein synthesis by binding to the 30S subunit of the ribosome

Question 23

Aminoglycosides are bacteri_____ antibiotics

Answer 23

Bactericidal

Question 24

Examples of aminoglycosides

Answer 24

Gentamycin, tobramycin, amikacin, streptomycin, neomycin

Question 25

How do tobramycin and gentamycin differ in bug coverage?

Answer 25

Tobramycin is MORE active against Pseudomonas
Gentamycin is MORE active against gram positives in synergy

Question 26

Bug coverage of amikacin

Answer 26

Entero
Non entero
TB
(reserved for when tobra/gent don’t work)

Question 27

Significant adverse effects of aminoglycosides

Answer 27

Nephrotoxicity
Ototoxicity

Question 28

What are the risk factors for nephrotoxicity with aminoglycosides?

Answer 28

Age
Renal disease
Volume depletion
Recent aminoglycoside exposure
Increased dose/duration
Other nephrotoxins

Question 29

What aminoglycosides have the highest risk of nephrotoxicity?

Answer 29

Gent = amik&raquo_space; tobra

Question 30

Which aminoglycosides have the highest risk of ototoxicity?

Answer 30

Neo&raquo_space; gent > tobra > amik

Question 31

MOA of fidaxomicin

Answer 31

Macrocyclic abx that inhibits protein synthesis by binding to the sigma subunit of RNA polymerase

Question 32

Bug coverage of fidaxomicin

Answer 32

**C diff only!!