Macrolides

Question 1

MOA of macrolides

Answer 1

• Similar to penicillin
• Prevents bacterial protein synthesis by binding to 50S subnunit of ribosomes (bacteriostatic)
• Broad spec

Question 2

Indications of macrolides

Answer 2

• RTI
• Chlamydia
• Penicillin allergy
• H pylori
• Skin + soft tissue infections

Question 3

Examples of macrolides

Answer 3

Azithromycin (long HL - OD)

• OTC to treat chlamydia

Clarithromycin (BD)

Erythromycin (QDS/BD. Safe in pregnancy)

Question 4

What are the side effects of macrolides?

Answer 4

GI disturbance (most with erythromycin)

Taste disturbance, tongue discolouration

QT prolongation
- MHRA: erythromycin inc risk of QT prolongation

Question 5

Which macrolides are used in pregnancy?

Answer 5

Erythromycin

Question 6

What are the counselling points for macrolides?

Answer 6

Before food (azithromycin)

After food (clarithromycin)

Indigestion remedies (azithromycin + erythromycin) - 2h before or after

Question 7

What are the interactions of macrolides?

Answer 7

Erythromycin + clarithromycin are enzyme inhibitors
Statins → myopathy
- Counsel: Stop course duration, don’t need to refer for alt

Warfarin → bleed
MHRA: erythromycin inc risk of bleed w rivaroxaban

Drugs that prolong QT interval → ventricular arrhythmias

Drugs that cause hypokalemia → INC risk of torsade de pointes