NEOMYCIN SULFATE-TRIAMCINOLONE ACETONIDE
Clinical safety rating: avoid
CYP3A4 inducers (eg phenytoin) may decrease efficacy and inhibitors may increase effects Can cause hyperglycemia and adrenal suppression with prolonged use.
Neomycin is an aminoglycoside antibiotic that binds to the 30S ribosomal subunit, inhibiting bacterial protein synthesis. Triamcinolone acetonide is a corticosteroid that induces phospholipase A2 inhibitory proteins, thereby decreasing prostaglandin and leukotriene synthesis, and exerts anti-inflammatory, antipruritic, and vasoconstrictive effects.
| Metabolism | Neomycin is minimally absorbed after topical application; any absorbed fraction is excreted renally unchanged. Triamcinolone acetonide is metabolized in the liver via CYP3A4. |
| Excretion | Neomycin: >90% orally administered excreted unchanged in feces; absorbed fraction (3-6%) excreted renally with 50% within 24 hours. Triamcinolone acetonide: primarily hepatic metabolism, renal excretion of metabolites (~40% as 11-keto derivatives), fecal excretion ~20%. |
| Half-life | Neomycin: 2-3 hours (normal renal function); in renal impairment, prolonged up to 12-24 hours. Triamcinolone acetonide: 2-5 hours (terminal). |
| Protein binding | Neomycin: ~10% bound to serum proteins. Triamcinolone acetonide: ~68% bound to albumin and corticosteroid-binding globulin. |
| Volume of Distribution | Neomycin: 0.1-0.2 L/kg (confined to extracellular fluid). Triamcinolone acetonide: 1.4-2.1 L/kg (wide distribution). |
| Bioavailability | Neomycin: Oral bioavailability <3% (poorly absorbed). Triamcinolone acetonide: Oral bioavailability ~23%; topical/otic minimal systemic absorption (<1% with intact skin). |
| Onset of Action | Topical: Anti-inflammatory effect of triamcinolone acetonide within 24-48 hours; antibacterial effect of neomycin within 12-24 hours. Otic: Clinical response within 1-2 days. |
| Duration of Action | Topical: Neomycin's antibacterial effect persists 8-12 hours; triamcinolone acetonide's anti-inflammatory duration is 6-12 hours. Otic: Duration of relief typically 4-6 hours. |
| Molecular Weight | Neomycin sulfate: 908.88 Da; Triamcinolone acetonide: 434.5 Da |
Topical: Apply thin film to affected area 2-4 times daily. Otic: Instill 3-4 drops into ear canal 2-3 times daily. Not for systemic use.
| Dosage form | CREAM |
| Renal impairment | Topical/otic: No systemic absorption expected; no adjustment needed. For systemic triamcinolone (not this formulation), adjust if GFR <30 mL/min: reduce dose by 50%. |
| Liver impairment | Topical/otic: No adjustment. For systemic triamcinolone (not this formulation): Child-Pugh A: no change; B: reduce dose by 50%; C: avoid or reduce by 75%. |
| Pediatric use | Topical: Apply sparingly 1-2 times daily for up to 2 weeks. Otic: age ≥1 year: 3 drops 3 times daily. |
| Geriatric use | Use caution due to skin thinning and increased systemic absorption risk. Limit application area and duration. Otic: same as adult. |
| 1st trimester | Avoid use due to potential ototoxicity and nephrotoxicity from neomycin; triamcinolone may increase risk of orofacial clefts. |
| 2nd trimester | Use only if benefit outweighs risk; limited data but corticosteroids associated with IUGR and adrenal suppression. |
| 3rd trimester | Avoid prolonged use due to risk of neonatal adrenal suppression (triamcinolone) and ototoxicity (neomycin). |
Clinical note
CYP3A4 inducers (eg phenytoin) may decrease efficacy and inhibitors may increase effects Can cause hyperglycemia and adrenal suppression with prolonged use.
| FDA category | Positive |
| Placental transfer | Triamcinolone acetonide crosses the placenta; neomycin is minimally absorbed systemically but may cross in small amounts. |
| Breastfeeding |
■ FDA Black Box Warning
None
| Common Effects | Hyperglycemia |
| Serious Effects |
Hypersensitivity to neomycin, triamcinolone, or any componentsSystemic fungal infectionsTuberculosis of the skinVaricella or herpes simplex infection at application sitePerforated tympanic membrane (for otic use)
| Precautions | Prolonged use may lead to overgrowth of nonsusceptible organisms including fungi, Systemic absorption of corticosteroids can cause reversible hypothalamic-pituitary-adrenal (HPA) axis suppression, Neomycin may cause ototoxicity and nephrotoxicity if systemically absorbed, especially in patients with impaired renal function, Avoid use on large areas of broken skin or for prolonged periods, Use with caution in patients with impaired renal function or hearing loss |
| Food/Dietary |
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| Neomycin is poorly absorbed orally, but triamcinolone is excreted in breast milk. Use with caution; monitor infant for growth suppression and adrenal effects. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy Category C. Triamcinolone acetonide: Corticosteroids are associated with increased risk of cleft palate, intrauterine growth restriction, and adrenal suppression in animal studies. Human data limited; risk likely related to dose and duration. Neomycin sulfate: Not teratogenic in animal studies but crosses placenta; potential for ototoxicity and nephrotoxicity theoretical. First trimester: Avoid unless essential. Second/third trimester: Use minimal effective dose; monitor fetal growth. Peripartum: Risk of neonatal adrenal suppression if maternal high-dose corticosteroids near term. |
| Fetal Monitoring | Monitor maternal blood pressure, glucose, and signs of infection (neomycin may mask symptoms). Fetal ultrasound for growth restriction if prolonged corticosteroid use. Neonatal assessment for adrenal insufficiency if high-dose triamcinolone near delivery. Avoid concurrent nephrotoxic drugs due to neomycin. |
| Fertility Effects | Triamcinolone acetonide: High doses may suppress HPA axis and alter gonadotropins, potentially impairing ovulation or spermatogenesis. Neomycin sulfate: No known direct effects on fertility. Reversible upon discontinuation. |
| No significant food interactions reported for topical use. Avoid alcohol if using on large area due to potential for increased systemic effects? (no known interaction). Generally, no restrictions. |
| Clinical Pearls | Neomycin sulfate is an aminoglycoside antibiotic active against gram-negative bacteria; triamcinolone acetonide is a potent corticosteroid that reduces inflammation. Topical combination is used for steroid-responsive dermatoses with secondary infection; caution with prolonged use due to potential for skin atrophy, systemic absorption, and ototoxicity from neomycin. Avoid use on large areas, broken skin, or under occlusion. Do not use in eyes or ear if tympanic membrane ruptured. Monitor for hypersensitivity (contact dermatitis) to neomycin. |
| Patient Advice | Apply a thin layer to affected area 2-4 times daily as directed; do not use longer than 2 weeks. · Avoid contact with eyes, mouth, or open wounds. · Do not cover with bandages unless instructed by doctor. · Stop use and tell doctor if rash, burning, or irritation occurs. · Not for children under 2 years unless prescribed. · Inform doctor if you have diabetes, tuberculosis, or fungal infections. |