CORTISPORIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CORTISPORIN (CORTISPORIN).
Corticosteroid (hydrocortisone) suppresses inflammation by inhibiting phospholipase A2 and cytokine production; neomycin and polymyxin B are aminoglycoside and polypeptide antibiotics respectively, that inhibit bacterial protein synthesis and disrupt cell membrane integrity.
| Metabolism | Hydrocortisone is primarily metabolized in the liver via reduction and conjugation; neomycin is minimally metabolized; polymyxin B is not significantly metabolized. |
| Excretion | Cortisporin is a combination product containing neomycin, polymyxin B, and hydrocortisone. Neomycin is primarily excreted unchanged in urine via glomerular filtration (up to 80% of absorbed dose); polymyxin B undergoes renal excretion (60% unchanged in urine); hydrocortisone is metabolized in the liver and excreted as glucuronide and sulfate conjugates in urine (90%) and feces (10%). For otic and ophthalmic suspensions, systemic absorption is minimal, and excretion data reflect absorbed fractions. Overall, renal excretion accounts for >80% of absorbed drug; fecal/biliary elimination is negligible. |
| Half-life | Terminal elimination half-life for absorbed neomycin is approximately 2-3 hours in patients with normal renal function; polymyxin B has a half-life of 6-8 hours; hydrocortisone half-life is 1.5-2 hours. Clinically, the otic suspension is not intended for systemic effect; local drug levels persist at the site of application for several hours, but systemic half-life is relevant only if significant absorption occurs (e.g., inflamed tympanic membrane or prolonged use). |
| Protein binding | Neomycin: <10% bound to plasma proteins; polymyxin B: approximately 50% bound; hydrocortisone: 90-93% bound to corticosteroid-binding globulin and albumin. Systemically absorbed fractions are minimal in normal use. |
| Volume of Distribution | Neomycin Vd: 0.25 L/kg (primarily extracellular fluid); polymyxin B Vd: 0.8 L/kg (distributes widely to tissues, excluding CSF); hydrocortisone Vd: 0.2-0.3 L/kg (bound in plasma, limited extravascular distribution). For otic/ophthalmic use, Vd values reflect absorbed drug; clinical relevance is minimal due to low systemic absorption. |
| Bioavailability | Otic suspension: approximately 0.1-0.5% absorbed across intact tympanic membrane; may increase to 5-10% if eardrum is perforated or mucosa is inflamed. Ophthalmic suspension: less than 0.1% absorbed systemically; <1% via nasal lacrimal drainage. Bioavailability is negligible for intended local effect. |
| Onset of Action | Otic suspension: onset of anti-inflammatory effect occurs within 1-2 hours; antibacterial effect begins within 2-4 hours after application. Ophthalmic suspension: onset of anti-inflammatory effect within 1-2 hours; antimicrobial effect within 2-4 hours. Topical otic or ophthalmic routes achieve local therapeutic concentrations without significant systemic absorption. |
| Duration of Action | Otic suspension: therapeutic effect (anti-inflammatory and antimicrobial) lasts 6-8 hours per dose; recommended dosing every 6-8 hours. Ophthalmic suspension: duration 4-6 hours; dosing every 4-6 hours. Prolonged use may lead to local irritation or superinfection. |
| Molecular Weight | Hydrocortisone: 362.5 Da; Neomycin: 322.3 Da; Polymyxin B: 1203.5 Da |
Instill 3-4 drops into affected ear(s) 3-4 times daily. Do not use for more than 10 days.
| Dosage form | CREAM |
| Renal impairment | No dosage adjustment required for topical otic administration. |
| Liver impairment | No dosage adjustment required for topical otic administration. |
| Pediatric use | Children: Instill 3 drops into affected ear(s) 3-4 times daily. Safety and efficacy in infants <1 year not established. |
| Geriatric use | Same as adult dosing; no specific adjustment needed. |
| 1st trimester | Corticosteroids are generally avoided in first trimester due to potential teratogenic effects, but topical use may be acceptable if benefit outweighs risk. Neomycin and polymyxin B are considered safe topically. |
| 2nd trimester | Topical use is considered safe; systemic absorption is minimal. |
| 3rd trimester | Topical use is considered safe; systemic absorption is minimal. |
Clinical note
Comprehensive clinical and safety monograph for CORTISPORIN (CORTISPORIN).
| Placental transfer | Corticosteroids cross the placenta; however, topical application results in negligible systemic absorption. Neomycin and polymyxin B are minimally absorbed. |
| Breastfeeding | Minimal systemic absorption with topical application; unlikely to produce significant levels in breast milk. Use with caution on large areas or broken skin. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to any componentPerforated tympanic membrane (otic use)Fungal or viral infections (untreated)Tuberculous infections
| Precautions | Prolonged use may result in overgrowth of non-susceptible organisms including fungi, Systemic absorption of hydrocortisone may cause hypothalamic-pituitary-adrenal axis suppression, Neomycin may cause ototoxicity if used in perforated eardrum or prolonged use, Polymyxin B may cause nephrotoxicity if absorbed systemically |
| Food/Dietary | No significant food interactions. Avoid alcohol if dizziness or balance issues are present. |
| Clinical Pearls |
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| Lactation Rating | L2: Safer (topical use likely compatible) |
| Teratogenic Risk | CORTISPORIN (neomycin/polymyxin B/hydrocortisone) otic suspension: Neomycin is an aminoglycoside that can cross the placenta; however, topical otic use results in negligible systemic absorption. No adequate and well-controlled studies in pregnant women. Animal studies with neomycin have shown potential for ototoxicity in offspring with high systemic doses. Polymyxin B is poorly absorbed systemically; no known teratogenic risk. Hydrocortisone: topical use at low concentrations has not been associated with teratogenicity in humans; risk of orofacial clefts with systemic corticosteroids in first trimester is low. Overall, due to minimal systemic absorption, risk is considered low. |
| Fetal Monitoring | No specific monitoring required for topical otic use. In case of prolonged or excessive use, monitor for signs of maternal ototoxicity or nephrotoxicity (neomycin) and adrenal suppression (hydrocortisone). |
| Fertility Effects | No known effects on fertility from topical otic use. |
| Cortisporin (neomycin/polymyxin B/hydrocortisone) is an otic suspension indicated for acute otitis externa. Avoid use if tympanic membrane is perforated due to risk of ototoxicity. Shake well before use. Limit duration to 10 days to minimize sensitization to neomycin. |
| Patient Advice | Instill drops with the affected ear facing upward, and remain in this position for 5 minutes to allow penetration. · Do not insert any objects into the ear canal during treatment. · Complete the full course even if symptoms improve. · Avoid getting water in the ear while swimming or bathing. · Report any hearing loss, dizziness, or worsening pain to your doctor. |