Pelvic Inflammatory Disease
Azithromycin

Azithromycin

Medium
Moderate
IV: $$ PO: $$ tablet, $ suspension

General Information

Community acquired pneumonia, Pertussis, Upper respiratory tract infections, Chlamydial infections, Mycobacterial infections

Neonatal: Liver function tests. Use with caution in infants with impaired hepatic function

Rare side effect: tinnitus

Neonatal:

  • Fewer adverse effects compared to erythromycin (much lower incidence of gastrointestinal side effects)
  • To date, the use of azithromycin in infants aged <1 month has not been associated with infantile hypertrophic pyloric stenosis (IHPS), but it is still recommended to monitor infants for this complication

Less risk for drug interactions compared to other macrolide antibiotics

Neonatal:

  • Erythromycin and clarithromycin, but not azithromycin, are inhibitors of the cytochrome P450 enzyme system (CYP3A subclass). Although drug interactions similar to those reported for erythromycin and clarithromycin have not been reported, monitoring of infants receiving medications metabolized by the cytochrome P450 enzyme system is recommended
  • Digoxin: May increase serum concentrations of digoxin
  • Tablet: 250mg
  • Suspension: 40 mg/mL
  • Injection: 500 mg/vial

Neonatal: 

  • Oral suspension: 40 mg/mL
  • Suspension may be administered via enteral tube
  • IV azithromycin is comparable in cost to IV erythromycin and is simpler to administer (once daily dosing, less vein irritation)

Neonatal:

  • Replacement for oral erythromcyin suspension (currently unavailable)
  • Azithromycin is more resistant to gastric acid, achieves high tissue concentrations and has a longer half-life than erythromycin allowing once daily administration and shorter treatment regimens (5 days versus 10 to 14 days)
  • Oral bioavailability: Approximately 40 to 50% and not affected by feeds

Antimicrobial class: Macrolide

Average serum half life: Infants and children: 55 hours

Route of Elimination: Neonatal:

  • 50% metabolized to inactive metabolites
  • 40% eliminated unchanged in bile
  • 10% eliminated unchanged by kidneys

Metabolism: Hepatic to inactive metabolites