E2 Erdman Macrolides Flashcards
3 macrolides we are talking about
Erythromycin
Azithromycin
Clarithromycin
(ACE)
which is a natural macrolide
Erythromycin
Azithromycin
Clarithromycin
Eryth
macrolide MOA
bind to 50S subunit
Macrolides cidal or static
static, but may be cidal in high concentrations against very susceptible organisms
Concentration dependent
A. Erythromycin
B. Azithromycin
C. Clarithromycin
B
time-dependent
A. Erythromycin
B. Azithromycin
C. Clarithromycin
A and C
3 mechs of resistance for Macrolides
- active efflux
- altered binding sites
- cross resistance between ALL macrolides
confers low-level resistance to the macrolides
A. active efflux
B. altered binding sites
C. cross resistance between ALL macrolides
A
confers high-level resistance to all macrolides
A. active efflux
B. altered binding sites
C. cross resistance between ALL macrolides
B
does NOT have best activity for GP aerobes
A. Azithromycin
B. Clarithromycin
C. Erythromycin
A
macrolide SoA:
GP aerobes
- group and viridans streptococci
- Streptococcus pneumoniae (ONLY PSSP)
- MSSA (staph a)
- Bacillus spp, Corynebacterium spp
Macrolide SoA:
GN aerobes, order of drugs and enhanced activity
A>C>E (cool spells ace)
T or F:
Macrolides have activity against Enterobacteriaceae
false, DO NOT
Macrolide SoA:
GN aerobes
actual bacterias
- Haemophilus influenzae (not erythromycin)
- Moraxella catarrhalis
- Neisseria spp
does NOT have activity against Haemo Influenzae
A. Azithromycin
B. Clarithromycin
C. Erythromycin
C
Macrolide SoA:
anaerobes
activity against upper airway anaerobes
Macrolide SoA:
atypical bacteria
ALL macrolides have excellent activity against
- Legionella - a DOC*
- Chlamydia spp
- Mycoplasma pneumoniae
- Ureaplasma urealyticum
Macrolide SoA:
“other organisms” highlighted option from slides
Mycobacterium avium complex
Absorption:
erytho base ->
erythro esters and ester salts ->
base: destroyed by gastric acid; enteric coated
esters: more acid stable and better absorbed
Absorption:
clarithromycin
acid stable and well absorbed from the GI tract (regardless of presence of food)
Absorption:
Azithromycin
acid stable, food does not affect absorption of tabs or suspension
does not have a very large Vd
A. Azithromycin
B. Clarithromycin
C. Erythromycin
C
T or F:
all macrolides penetrate the CSF well
false, minimal CSF pen
All 3 macrolides extensively distribute into _____ and _____
tissues and cells (macrophages and neutrophils)
erythromycin is excreted in ____ and metabolized by ______
bile
CYP450
Clarithromycin is metabolized and partially eliminated by the ______
kidney
Clarithromycin requires dose adjustment when CrCl < __?
30
Azithromycin is eliminated by?
biliary excretion
has the longest half life of 68 hours
A. Azithromycin
B. Clarithromycin
C. Erythromycin
A
clarithromycin metabolized in liver by ?
CYP450
which macrolides are removed during hemodialysis or peritoneal dialysis
none you fool
macrolide clinical uses:
RTI’s
- disease state
- especially for _____ coverage
comm acqu pneumonia
atypical
community acquired pneumonia:
__________ for outpatients OR
combined with _______ for inpatients
monotherapy
ceftriaxone
which macrolide to treat STDs?
what dose?
azithromycin, one gram
use of azithro for an STD is treating urethritis or cervicitis from what bacteria
chlamydia trachomatis
what is MAC
mycobacterium avium complex infection
used alone as prophylaxis for MAC
A. Azithromycin
B. Clarithromycin
C. Erythromycin
A
used with ethambutol and/or rifabutin for treatment of MAC
A. Azithromycin
B. Clarithromycin
C. Erythromycin
B
T or F:
macrolides are frequently used as alternatives for penicillin-allergic pts
true
main AE for macrolides and how to mitigate it
GI upset, take with food
most commonly causes GI upset
A. Azithromycin
B. Clarithromycin
C. Erythromycin
C
which of the following can cause Thrombophlebitis with IV use
A. Azithromycin
B. Clarithromycin
C. Erythromycin
A and C
how do you partially avoid thrombophlebitis from IV erythro or azithro (3)
dilution of dose
slow admin
infuse into large vein
“other” highlighted AE of macrolides
QTc **
Does NOT inhibit CYP450
A. Azithromycin
B. Clarithromycin
C. Erythromycin
A
macrolide drug interactions, may increase conc of what drugs? (7) (start with important one)
- warfarin
- theophylline
- carbamazepine
- cyclosporine
- phenytoin
- digoxin
- valproic acid
(also azithro is not affiliated with these*)
Which of the following antibiotics does NOT have activity against atypical bacteria (e.g., Legionella pneumophila)?
A. Azithromycin
B. Levofloxacin
C. Amoxicillin-clavulanate
D. Clarithromycin
E. Moxifloxacin
C
Which of the following antibiotics is least likely to interact with warfarin?
A. Azithromycin
B. Levofloxacin
C. Ciprofloxacin
D. Clarithromycin
E. Moxifloxacin
A
