Dose and Administration^1,2,3

1. IV infusion by syringe pump over 60 minutes.

	Dose
Preterm infants	10 mg/kg/dose 6 hourly
Term infants	12.5 mg/kg/dose 6 hourly

Indications

1. Suspected/proven infection with Mycoplasma pneumoniae, Ureaplasma urealyticum, and Chlamydia trachomatis.
2. As a substitute for penicillin in situations of significant hypersensitivity to penicillin.
3. Treatment for and prophylaxis against Bordetella pertussis.

Contraindications¹

1. Known hypersensitivity to erythromycin
2. Administration to patients already taking cisapride is contraindicated.

Warnings¹:

1. If allergic reactions, from skin eruptions to anaphylaxis, occur discontinue erythromycin immediately.
2.  Prolonged use may result in superinfection. This may be accompanied by Clostridium difficile- associated diarrhoea which may range from mild diarrhoea to fatal pseudomembranous colitis. Discontinue erythromycin immediately and avoid co-administration of drugs which delay peristalsis eg. opiates.
3. Prolongation of QT interval and development of ventricular arrhythmias can occur and may be associated with too rapid administration.

Precautions

1. Liver disease. Caution in infants with jaundice, liver dysfunction, and biliary tract disease.
2. Caution in preterm infants, especially extreme immaturity

Drug Interactions

• Avoid concomitant use with cisapride
• Erythromycin may increase the effects of digoxin, midazolam, corticosteroids, fentanyl, milrinone, phenytoin, rifampicin, caffeine citrate, theophylline.
• Erythromycin may decrease the effect of: BCG

Clinical Pharmacology

Bacteriostatic antibiotic which suppresses bacterial protein synthesis. The antibacterial spectrum is similar to penicillin but extended to include Mycoplasma pneumoniae, Ureaplasma urealyticum and Chlamydia trachomatis.

Vd 45% of body weight in adults. Antibacterial levels are achievable in all tissues except brain and CSF. Highly bound (64-98%) to human plasma protein. Hepatic excretion into bile as active compound. Only 5-15% of administered dose excreted in the active form in the urine. Plasma half life equals 2-4 hours.

Possible Adverse Effects¹

1. Allergic reactions, cardiotoxicity , including prolongation of QT interval, ventricular arrhythmias. See “warnings”
2. More common reactions are thrombophlebitis, venous irritation, and gastrointestinal eg. vomiting, diarrhoea. These can be avoided by administering slowly as a diluted solution.
3. Other reactions that may occur are: bradycardia, hypotension, ototoxicity, hepatic impairment, hypertrophic pyloric stenosis.

Special Considerations

1. Monitor LFTs, B.P., heart rate.
2. Hepatic dysfunction, use cautiously.
3. I.V. push is not recommended due to local irritation and cardiovascular effects. See “warnings”
4. At low doses erythromycin may inhibit the effect of penicillin, but at high doses may act synergistically.