Erythromycin

Question 1

Drug class?

Answer 1

Macrolide

Question 2

How does it work?

Answer 2

• Broad spectrum bacteriostatic Abx - Inhibits bacterial protein synthesis by binding reversibly to 5s subunit of bacterial ribosomes.

Question 3

Indications?

Answer 3

1. Upper Respiratory Tract infections: tonsillitis, peritonsillar abscess, pharyngitis, laryngitis, sinusitis, secondary infections in influenza and common colds
2. Lower Respiratory Tract infections: tracheitis, acute and chronic bronchitis, pneumonia (lobar pneumonia, bronchopneumonia, primary atypical pneumonia), bronchiectasis, Legionnaire’s disease
3. Ear infection: otitis media and otitis externa, mastoiditis
4. Oral infections: gingivitis, Vincent’s angina
5. Eye infections: blepharitis
6. Skin and soft tissue infections: boils and carbuncles, paronychia, abscesses, pustular acne, impetigo, cellulites, erysipelas
7. Gastrointestinal infections : cholecystitis, staphylococcal enterocolitis

Question 4

Side-effects?

Answer 4

Common: nausea, vomiting, diarrhoea, rash, phlebitis
Rarely: reversible hearing loss, cholestatic jaundice

Question 5

Possible interactions?

Answer 5

Is an inhibitor of P450 system so will increase concentrations of drugs metabolised by that system.
- Antihistamines: Inhibits antihistamine metabolism # risk of cardiac dysrhythmias