ERYGEL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ERYGEL (ERYGEL).
Erythromycin is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, blocking the translocation of peptidyl-tRNA.
| Metabolism | Hepatic metabolism via CYP3A4; major metabolite is demethylerythromycin. |
| Excretion | Primarily hepatic metabolism; less than 10% excreted renally as unchanged drug. Biliary excretion is minimal. |
| Half-life | Terminal elimination half-life is approximately 1.6 hours (range 1.0–2.5 hours) after topical application, too short to accumulate with daily use. |
| Protein binding | Approximately 99% bound to serum proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution not clinically relevant for topical formulation; systemic absorption is minimal (<0.1% of applied dose). |
| Bioavailability | Bioavailability after topical application is extremely low (<0.1%) due to minimal percutaneous absorption. |
| Onset of Action | Onset of clinical effect (reduction of acne lesions) is typically observed after 4–8 weeks of once-daily topical application. |
| Duration of Action | Duration of action is sustained throughout the dosing interval with once-daily application; effect persists for at least 24 hours after each dose. |
Apply a thin layer to affected areas twice daily. Topical use only.
| Dosage form | GEL |
| Renal impairment | No dose adjustment required. |
| Liver impairment | No dose adjustment required. |
| Pediatric use | Not recommended for children under 12 years; for ages 12 and older, same as adult dosing. |
| Geriatric use | No specific dose adjustment; use caution due to potential skin irritation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ERYGEL (ERYGEL).
| Breastfeeding | Topical erythromycin is considered compatible with breastfeeding due to negligible systemic absorption. M/P ratio not determined; trace amounts in milk are unlikely to cause adverse effects in the infant. |
| Teratogenic Risk | Erythromycin (topical) is classified as FDA Pregnancy Category B. Systemic absorption is minimal; thus, no fetal risks have been documented. No known teratogenicity in first trimester. Second and third trimesters: no adverse fetal effects reported. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to erythromycin or any macrolide antibiotic.","Concomitant use with ergotamine or dihydroergotamine due to risk of ergotism.","Use in patients with pre-existing QT prolongation or history of ventricular arrhythmias."]
| Precautions | ["Potential for QT prolongation and risk of cardiac arrhythmias, especially with concomitant use of other QT-prolonging drugs.","Risk of antibiotic-associated colitis (pseudomembranous colitis) due to Clostridium difficile.","Hepatic impairment may require dose adjustment."] |
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| No specific monitoring required beyond routine prenatal care. If used for acne, assess skin irritation at application site. |
| Fertility Effects | No known adverse effects on fertility. No human studies available; animal studies show no impairment of fertility. |