ERYDERM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ERYDERM (ERYDERM).
Erythromycin, a macrolide antibiotic, binds to the 50S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis by blocking translocation.
| Metabolism | Erythromycin is metabolized primarily in the liver via demethylation by CYP3A4. |
| Excretion | Erythromycin is primarily excreted via the biliary route (~80%) as unchanged drug and metabolites, with renal excretion accounting for ~10-15%. Fecal elimination is minimal (~2-4%). |
| Half-life | Terminal elimination half-life is approximately 1.5-2 hours in adults with normal renal function, but can extend to 4-6 hours in patients with severe hepatic impairment. |
| Protein binding | Erythromycin is approximately 70-90% bound to plasma proteins, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution is approximately 0.6-0.8 L/kg, indicating distribution into extracellular and intracellular fluid, with high tissue penetration. |
| Bioavailability | Oral erythromycin base: 35-45% (enteric-coated); estolate: 25-40%; ethylsuccinate: 70-80% (food decreases absorption). Intravenous: 100%. Topical: minimal systemic absorption (<1%). |
| Onset of Action | Oral: 1-2 hours; Intravenous: 30 minutes; Topical: 2-3 days for clinical improvement in acne. |
| Duration of Action | Oral/IV: 6-8 hours; Topical: continuous with regular application; clinical effect in acne may require 4-8 weeks. |
Topical: Apply a thin film to affected area twice daily for 2-4 weeks.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for topical use due to minimal systemic absorption. |
| Liver impairment | No dose adjustment required for topical use. |
| Pediatric use | Children ≥2 years: Apply topically twice daily for 2 weeks; children <2 years: not recommended. |
| Geriatric use | No specific dose adjustment needed; use same as adult dosing. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ERYDERM (ERYDERM).
| Breastfeeding | Minimal systemic absorption; unlikely to be excreted into breast milk. M/P ratio not available. Considered compatible with breastfeeding. |
| Teratogenic Risk | Erythromycin (topical) has no known teratogenic effects; systemic absorption minimal. No fetal risk documented in any trimester. |
| Fetal Monitoring | No specific monitoring required due to negligible systemic exposure. |
■ FDA Black Box Warning
No FDA black box warning for topical erythromycin.
| Serious Effects |
Hypersensitivity to erythromycin or any component; concurrent use with ergotamine or dihydroergotamine may cause ergotism.
| Precautions | May cause irritation, sensitization, or superinfection; prolonged use may result in fungal overgrowth. |
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| Fertility Effects | No known effects on fertility. |