• Type: Macrolide
  • Dosage Forms: PO, IV, topical
  • Common Trade Names:

Adult Dosing

  • 250-500mg PO q6h


  • 3mg/kg IV over 20-30min, 30-90min prior to endoscopy
    • Achieves endoscopy conditions equal to lavage[1]

Pediatric Dosing

  • Mild-moderate infections: 30-50 mg/kg/day PO divided q6-8hr
  • Severe infection: 60-100 mg/kg/day PO divided q6-8hr

Special Populations


  • Allergy to class/drug
  • QT prolongation

Adverse Reactions


  • Torsades, ventricular dysrhythmias
  • Pseudomembranous colitis
  • Hypertrophic pyloric stenosis
  • Seizures


  • nausea/vomiting
  • diarrhea
  • urticaria
  • transaminitis
  • urticarial rash


  • Half-life: 2 hours
  • Metabolism: Liver
  • Excretion: Bile/Renal
  • Mechanism of Action: Binds to 50S ribosomal unit β†’ inhibiting protein synthesis

Antibiotic Sensitivities[2]

Group Organism Sensitivity
Gram Positive Strep. Group A, B, C, G I
Strep. Pneumoniae I
Viridans strep X1
Strep. anginosus gp X1
Enterococcus faecalis R
Enterococcus faecium R
Staph. Epidermidis I
C. jeikeium R
L. monocytogenes S
Gram Negatives N. gonorrhoeae I
N. meningitidis X2
Moraxella catarrhalis I
H. influenzae I
E. coli R
Klebsiella sp R
E. coli/Klebsiella ESBL+ R
E coli/Klebsiella KPC+ R
Enterobacter sp, AmpC neg R
Enterobacter sp, AmpC pos R
Serratia sp X1
Serratia marcescens R
Salmonella sp R
Shigella sp R
Proteus mirabilis X1
Proteus vulgaris R
Providencia sp. X1
Morganella sp. X1
Citrobacter freundii X1
Citrobacter diversus X1
Citrobacter sp. X1
Aeromonas sp X1
Acinetobacter sp. R
Pseudomonas aeruginosa R
Burkholderia cepacia R
Stenotrophomonas maltophilia R
Yersinia enterocolitica R
Francisella tularensis X1
Brucella sp. R
Legionella sp. S
Pasteurella multocida X1
Haemophilus ducreyi S
Vibrio vulnificus X1
Misc Chlamydophila sp S
Mycoplasm pneumoniae S
Rickettsia sp I
Mycobacterium avium X1
Anaerobes Actinomyces S
Bacteroides fragilis R
Prevotella melaninogenica X1
Clostridium difficile X1
Clostridium (not difficile) I
Fusobacterium necrophorum R
Peptostreptococcus sp. I


  • S susceptible/sensitive (usually)
  • I intermediate (variably susceptible/resistant)
  • R resistant (or not effective clinically)
  • S+ synergistic with cell wall antibiotics
  • U sensitive for UTI only (non systemic infection)
  • X1 no data
  • X2 active in vitro, but not used clinically
  • X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
  • X4 active in vitro, but not clinically effective for strep pneumonia

See Also


  1. ↑ Pateron D, et al. Erythromycin infusion or gastric lavage for upper gastrointestinal bleeding: a multicenter randomized controlled trial. Ann Emerg Med. 2011; 57(6):582-589.
  2. ↑ Sanford Guide to Antimicrobial Therapy 2014