Clarithromycin

Question 1

What class of antibiotic is clarithromycin?

Answer 1

Macrolide

Question 2

What other macrolide antibiotics are used?

Answer 2

Erythromycin
Azithromycin

Question 3

What is the mechanism of action of macrolides?

Answer 3

They target the 50s subunit of the bacterial ribosome

Question 4

What is the effect of macrolides?

Answer 4

Inhibit bacterial protein synthesis by preventing translocation

Question 5

What are the indications for macrolides?

Answer 5

LRTI
Bacterial URTI
Cellulitis
H. pylori eradication
Chlamydia

Question 6

What dose of clarithromycin is typical?

Answer 6

Up to 500mg BD depending on infection

Question 7

What dose of erythromycin is typical?

Answer 7

Up to 500mg QDS

Question 8

What are the common side effects of macrolides?

Answer 8

GI upset
Taste/smell disturbance

Question 9

What are the important side effects of macrolides?

Answer 9

QT prolongation
Arrhythmias
Hepatotoxicity
Steven-Johnson syndrome

Question 10

What are the cautions for macrolides?

Answer 10

Renal impairment
Predisposition to QT prolongation
Electrolyte disturbances

Question 11

What do macrolides interact with?

Answer 11

Theophylline (increased plasma theophylline concentration)
Warfarin (increased anticoagulant effect)
Antipsychotics (risk of ventricular arrhythmias)
Colchicine - increased risk of toxicity
Statins - increased risk of myopathy

Question 12

What monitoring doe macrolides require?

Answer 12

Check ECG if any cardiac symptoms

Question 13

What information should be given to patients taking macrolides?

Answer 13

Patients should complete the full course of antibiotics