Erythromycin
ERYTHROCIN
What it isMacrolide inhibiting the 50S ribosomal subunit; atypical infection, and used off-label as a prokinetic.
Why this oneIts motilin agonism makes it useful for gastroparesis, which no other antibiotic offers.
What limits itA strong CYP3A4 inhibitor and QT prolonger, so interactions are constant. GI upset limits the dose; tachyphylaxis develops in prokinetic use.
FDA-approved for
- bacterial infections (1952)
- pertussis (1952)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Susceptible infections (usual) | Adults | 400 mg QID (q6h) | 400 mg QID (q6h) | 4 g/day |
| Susceptible infections (usual) | Children | 30-50 mg/kg/day divided q6h | 30-50 mg/kg/day | 100 mg/kg/day (severe) |
| Streptococcal prophylaxis (rheumatic heart disease) | Adults | 400 mg BID | 400 mg BID | 400 mg BID |
Renal Undefined
Hepatic Undefined
Instructions
- May be administered without regard to meals
- Treat streptococcal infections for at least 10 days
Contraindications
- Concomitant terfenadine, astemizole, pimozide, or cisapride
- Concomitant CYP3A4-metabolized statins (lovastatin, simvastatin) — rhabdomyolysis risk
Cautions
- Hepatotoxicity/hepatic dysfunction
- QT prolongation and ventricular arrhythmias incl. torsades de pointes
- C. difficile/pseudomembranous colitis
- Reversible hearing loss (renal insufficiency, high doses)
Adverse reactions
- Nausea
- Vomiting
- Abdominal pain
- Diarrhea
- Anorexia
- Allergic reactions (urticaria to anaphylaxis)
Pregnancy No evidence of teratogenicity or reproductive harm in animal studies
Lactation Undefined
NO BOXED WARNINGS
Principal riskA strong CYP3A4 inhibitor; QT prolongation
Cost, est. cash$300–$2,500/month
Generic entry1990
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.
Mechanism of action: Erythromycin ballicule
Open Erythromycin in the interactive console ↗
Memory aids: mascots and interaction avatars
macrolide ring
erythro = red
