III. Mechanism

  1. See Macrolide

IV. Adverse Effects

  1. Gastrointestinal upset
  2. Nausea
  3. Cholestatic Jaundice
  4. Multiple Drug Interactions
  5. Candida Vaginitis infection
  6. Gram Negative Folliculitis
  7. Myasthenia Gravis exacerbation
  8. Hypertrophic Pyloric Stenosis (age <45 days)
  9. QT Prolongation
    1. Class effect with Macrolides
    2. Three fold increased risk of Sudden Cardiac Death while on Azithromycin
    3. Higher risk with known QTc Prolongation, Hypokalemia, Hypomagnesemia, Class IA or III Antiarrhythmics
    4. Ray (2013) N Engl J Med 366(20): 1881-90 [PubMed]

V. Drug Interactions

  1. See Macrolide
  2. Strong CYP3A4 Inhibitor
    1. Numerous Drug Interactions
  3. Warfarin
    1. May increase INR

VI. Pharmacokinetics

  1. Half life: 1.5 hours

VII. Dosing

  1. See Erythromycin Ethyl Succinate (EES)
  2. See Erythromycin Lactobionate
  3. See Pertussis
  4. Erythromycin Oral Preparations (Take with food to reduce GI Upset)
    1. Erythromycin Base
      1. Adult: Take 250 to 500 mg orally four times daily OR 333 mg orally three times daily
      2. Child: Take 30 to 50 mg/kg/day divided four times daily
    2. Erythromycin Ethyl Succinate (EES)
      1. Adult: 400 mg orally four times daily
      2. Child: 30-50 mg/kg/day divided orally four times daily
  5. Erythromycin Parenteral Preparation: Erythromycin Lactobionate
    1. Dose: 15 to 20 mg/kg/day IV divided every 6 hours
    2. Maximum: 4 grams

VIII. Safety

  1. Pregnancy Category B
  2. Considered safe in Lactation

IX. Adverse Effects

  1. Myasthenia Gravis exacerbation
  2. Hypertrophic Pyloric Stenosis (age <45 days)
  3. Strong CYP3A4 Inhibitor
    1. Numerous Drug Interactions
    2. Serious interactions resulting in death have occurred
  4. Warfarin
    1. May increase INR
  5. QT Prolongation
    1. Class effect with Macrolides
    2. Three fold increased risk of Sudden Cardiac Death while on Azithromycin
    3. Higher risk with known QTc Prolongation, Hypokalemia, Hypomagnesemia, Class IA or III Antiarrhythmics
    4. Ray (2013) N Engl J Med 366(20): 1881-90 [PubMed]

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Cost: Medications

erythromycin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
ERYTHROMYCIN 0.5% EYE OINTMENT Generic $2.63 per gram
ERYTHROMYCIN 2% GEL Generic $0.75 per gram
ERYTHROMYCIN 2% SOLUTION Generic $0.41 per ml
ERYTHROMYCIN 200 MG/5 ML SUSP Generic $1.65 per ml
ERYTHROMYCIN 250 MG TABLET Generic $4.75 each
ERYTHROMYCIN 400 MG/5 ML SUSP Generic $2.55 per ml
ERYTHROMYCIN 500 MG TABLET Generic $8.25 each
ERYTHROMYCIN DR 250 MG TABLET Generic $4.53 each
ERYTHROMYCIN DR 500 MG TABLET Generic $4.85 each
ERYTHROMYCIN-BENZOYL GEL Generic $1.70 per gram