Erythromycin is a macrolide antibiotic obtained from Streptomyces erythreus in 1952. It contains a 14 atom macrocyclic lactone ring with two attached deoxy sugars. Erythromycin is used to treat bone, joint, respiratory, GI, and ear infections as well as pharyngitis, and is an alternative for patients with penicillin hypersensitivity. It is dosed between 250-500mg every 6-12 hours depending on the condition. Side effects include hearing loss, rashes, liver toxicity, and kidney damage. Erythromycin works by blocking the 50S ribosomal RNA to prevent protein synthesis. It is metabolized in the liver and eliminated in

1. PRESENTED BY
DR. ASHFAQ AFRIDI
Erythromycin

2. Introduction
Class: Erythromycin is an intermediate spectrum
macrolide antibiotic
Obtained from: Streptomyces erythreus in 1952.
Structure: It contains two deoxy sugars attached to a
14 atom macrocyclic lactone ring
 Chemical formula: C37H67NO13
Molecular weight : 773.93 g/ mol

3. Chemical Structure

5. Indications
For susceptible microbiological entities in:
Bone and Joint infections
Lower respiratory tract infection (i.e. pneumonia,
bronchitis etc.)
GI infections
Otitis
Prevention of pharyngitis
Usually preferred as alternative to the patient having
penicillin hypersensitivity
As a pro-kinetic in gastroparesis

6. Dosage
Depending on the condition, doses of erythromycin
tend to range from the following:
250 milligrams (mg) to 500 mg, every six to 12 hours
500 mg every 12 hours
333 mg every eight hours
Adults: 250mg q.i.d for 10 days, max 4g/d
Children: 30-50mg/kg/d for 10 days, max 4g/d

7. Side Effects
Otto-toxicity resulting in hearing loss
Tinnitus
Hypersensitivity reactions leading to urticaria &
rashes
Steven Johnson syndrome
QT interval prolongation.
Nephrotoxicity (some time leads to kidney failure in
chronic use)
NVD
Cholestatic Jaundice

8. Pharmacodynamics
The antibacterial action of erythromycin and other
macrolides may be inhibitory or bactericidal (in high
concentration) for susceptible organisms
It blocks 50s Ribosomal RNA (Large sub unit of
ribosome).
Thus prevent protein synthesis

9. Pharmacokinetics
Basic in nature
Destroyed by stomach acid
Metabolized by CYP-3-A-4
Hepato-biliary secretion is the main process
 About 95 % drug is eliminated via this route
5% via urine

10. ContraIndications
Contraindicated in case of hypersensitivity to
macrolide antibiotics
Warning & Precautions:
 Use with caution in patients with
 liver and kidney disease, prolonged QT interval
 Take on empty stomach
Pregnancy: Category B

11. Interactions
Statins
Rifampin
Al & Mg containing Antacids
Oral anticoagulants
Astemizole
Benzodiazepines
Carbamazepine
Cyclosporin
Digoxin

12. THANKS