Macrolides/Ketolides Flashcards
Are macrolides given in an outpatient or inpatient setting for their broad coverage of respiratory pathogens?
Outpatient setting
How can macrolides combat resistance to develop a better coverage against S. pneumoniae?
Combine with a ketolide (telithromycin)
What is unfortunate about using telithromycin (ketolide) with macrolides?
Consist of more hepatotoxicity than macrolides
Which is the class patriarch of macrolides?
Erythromycin
Which macrolide has little use except as a GI stimulant, due to toxicity, drug interactions, and limited spectrum?
Erythromycin
What is the MOA of the macrolides?
Binds to the 50s ribosomal subunit and blockade of bacterial protein synthesis leads to bacteriostatic effects
What is the mechanism of resistance of the macrolides?
Alteration of macrolide target site (50s ribosomal subunit) by two things
- bacterial enzymes OR
- drug efflux by an active pump
Macrolides and ketolides have a good spectrum over which bacteria?
- Atypicals
- H. influenzae
- M. catarrhalis
- H. pylori
- Mycobacterium avium
What adverse events could occur with the use of macrolides and ketolides?
- GI effects
- Hepatotoxicity (rare)
- QT prolongation
Which macrolide or ketolide worsens GI effects?
Erythromycin since it’s a prokinetic agent for pts with impaired GI motility
Which macrolide or ketolide increases hepatotoxicity?
Telithromycin; could lead to transplant or death
Who should use macrolides and ketolides with caution to minimize the risk of QT prolongation?
- Preexisting heart conditions
- Pts on antiarrhythmics
- Taking interacting drugs
Macrolides and ketolides inhibit what enzyme causing major drug interactions?
- CYP450
Which macrolide or ketolide does not inhibit CYP450 enzymes?
Azithromycin
Which macrolide or ketolide has a prolonged half-life being adequate for most short course use of most infections?
Azithromycin
