Infectious Diseases I: Macrolides

Question 1

Macrolide MOA

Answer 1

binds to 50S subunit of bacteria ribosome and inhibits protein synthesis

Question 2

General coverage of macrolides

Answer 2

good atypical (legionella, chlamydia, mycoplasma)
Haemophilus

Question 3

Typically infections that are treated w/ macrolides

Answer 3

community acquired URTI and LRTIs

certain STD

Question 4

Macrolide warnings

Answer 4

QT prolongation (highest w/ erythromycin)
Hepatotoxicity
Exacerbation of myasthenia gravis

Question 5

Clarithromycin and erythromycin should not be used with which statins?

Answer 5

Lovastatin

simvastatin

Question 6

Macrolide side effects

Answer 6

GI upset (most with erythromycin)
incr LFTs
taste perversion
severe skin reactions (SJS/TENS with azith)

Question 7

Azithromycin ER suspension

Answer 7

Zmax

Question 8

Biaxin

dosing

Answer 8

Clarithromycin
250-500 mg Q12h
XL: 1 gram daily
CrCL < 30: adjustment needed

Question 9

Biaxin has better gram +/- coverage

Answer 9

gram +

Question 10

Erythromycin brands

Answer 10

E.E.S
Ery-Tab
EryPed
Erythrocin

Question 11

Which macrolide is not a substrate AND inhibitor of Cyp3a4

Answer 11

Azithromycin - fewer clinically significant interactions than others

Question 12

What other action does erythromycin have besides antibiotic effects?

Answer 12

Incr gastric motility

not used often to treat infections

Question 13

Common uses of azithromycin

Answer 13

CAP
strep throat
COPD exacerbation
Chlamydia
gonorrhea (combo therapy)
MAC prophylaxis
Travler's diarrhea

Question 14

Common uses of clarithromycin

Answer 14

CAP
strep throat
H. pylori treatment