AKNE-MYCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AKNE-MYCIN (AKNE-MYCIN).
Erythromycin, a macrolide antibiotic, binds to the 50S subunit of bacterial ribosomes and inhibits protein synthesis by blocking translocation of peptidyl-tRNA. Topically, it reduces Propionibacterium acnes colonization and exhibits anti-inflammatory properties.
| Metabolism | Not systemically absorbed to a clinically significant degree after topical application. If absorbed, erythromycin is primarily metabolized by hepatic cytochrome P450 enzymes, mainly CYP3A4. |
| Excretion | Primarily renal (60-80% unchanged); minor biliary/fecal (15-30%) |
| Half-life | 2-3 hours (normal renal function); up to 24-36 hours in severe renal impairment |
| Protein binding | Bound primarily to albumin (10-20%) |
| Volume of Distribution | 0.2-0.3 L/kg, indicating limited extravascular distribution (primarily extracellular fluid) |
| Bioavailability | Topical: 2-5% (minimal systemic absorption); oral: 75-85% |
| Onset of Action | Topical: 48-72 hours for visible reduction in inflammatory lesions; oral: 2-4 hours for systemic effect |
| Duration of Action | Topical: 8-12 hours between applications; oral: 6-8 hours, requiring multiple daily dosing |
Topical application of 2% solution twice daily to affected areas.
| Dosage form | OINTMENT |
| Renal impairment | No dosage adjustment required for topical use; systemic absorption negligible. |
| Liver impairment | No dosage adjustment required for topical use; systemic absorption negligible. |
| Pediatric use | Safety and efficacy not established in children under 12 years; for age ≥12 years, same as adult dosing. |
| Geriatric use | No specific adjustments; use with caution due to potential increased skin sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AKNE-MYCIN (AKNE-MYCIN).
| Breastfeeding | Erythromycin is excreted in human milk in small amounts. Topical Akne-Mycin results in negligible systemic absorption, making significant infant exposure unlikely. M/P ratio not reported for topical use; oral erythromycin M/P ratio is approximately 0.5. Caution is advised, but use is generally compatible with breastfeeding. |
| Teratogenic Risk | Akne-Mycin (erythromycin topical) is Pregnancy Category B. No evidence of teratogenicity in animal studies; adequate human studies are lacking. Systemic absorption is minimal with topical use, but risk cannot be completely excluded. First trimester: low risk, but use only if clearly needed. Second and third trimesters: generally considered safe with minimal systemic exposure. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to erythromycin or any component of the formulation. Concurrent use with pimozide or ergot alkaloids (potential for QT prolongation and ergotism, though systemic absorption low).
| Precautions | For external use only; avoid contact with eyes, mouth, and mucous membranes. May cause skin irritation, burning, stinging, or dryness. Reported cases of pseudomembranous colitis with topical use (rare). Use with caution in patients with hepatic impairment if significant systemic absorption occurs. Cross-resistance with other macrolides may develop. Use during pregnancy only if clearly needed (category B). |
| Food/Dietary | No specific food interactions. Take with or without food. Avoid excessive intake of spicy or greasy foods, which may exacerbate acne. |
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| Fetal Monitoring | No specific monitoring required due to topical application and low systemic absorption. Routine pregnancy monitoring is sufficient. If signs of systemic toxicity occur (rare), monitor liver function and hearing. |
| Fertility Effects | No known adverse effects on fertility. Erythromycin does not impair reproductive function in animal studies. Topical use is unlikely to impact fertility. |
| Clinical Pearls | Akne-Mycin (erythromycin topical) is effective for mild to moderate acne vulgaris. It can be combined with benzoyl peroxide to reduce antibiotic resistance. Avoid use with other topical erythromycin products to prevent overuse. Monitor for local skin reactions like erythema, scaling, or itching. |
| Patient Advice | Apply a thin layer to affected areas once or twice daily as directed. · Wash skin gently with mild soap and pat dry before application. · Avoid contact with eyes, mouth, and mucous membranes. · Do not use more often than prescribed; overuse can increase irritation. · Inform your doctor if you develop severe redness, peeling, or discomfort. · Use sunscreen daily as this medication may increase sun sensitivity. |