Macrolides

Question 1

Mechanism of action of macrolides

Answer 1

Broad spectrum and bacteriostatic - binds to 50s subunit of ribosome inhibiting protein synthesis

Question 2

Which other antibiotic do macrolides have a similiar spectrum to?

Answer 2

Penicillins - alternative to use if pen allergic

Question 3

MHRA alert for erthyromycin

Answer 3

Caution required due to cardiac risks (QT interval prolongation); drug interaction with rivaroxaban
Increased risk of infantile hypertrophic pyloric stenosis (monitor baby for irritability whilst feeding, avoid in neonates under 2 weeks)

Question 4

Prominent side effect of all macrolides

Answer 4

QT prolongation
Hepatoxicity (report signs of cholestatic jaundice)
Hearing impairment
Antibiotic associated colitis

Question 5

Examples of macrolides

Answer 5

Erythromycin, azithromycin and clarithromycin

Question 6

Macrolides and pregnancy

Answer 6

Clarithromycin avoid particularly in 1st trimester

Erythromycin - okay (pros outweigh risks)

Question 7

Macrolide interactions (erythromycin and clarithromycin

Answer 7

Is a potent CYP450 (CYP3A4) inhibitor - increases anticoagulant effect of warfarin and risk of myopathy with statins
Also carbamazepine, theophyllin and ticagrelor

Question 8

What are macrolides normally used to treat

Answer 8

CAP, cellulitis, RTIs, chest infections, acute OM and H.pylori

Question 9

Counselling for azithromycin and erythromycin GR tabs

Answer 9

Do not take indigestion remedies 2 hours before or after you take this med

Question 10

Counselling for azithromycin caps and erythromycin GR tabs

Answer 10

Take this med when your stomach is empty. this means an hour before food or 2 hours after food

Question 11

Counselling for MR clarithromycin MR tabs

Answer 11

Take with or just after food or a meal