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Neomycin, Colistin, Hydrocortisone, and Thonzonium

Generic name: colistin sulfate/hydrocortisone/neomycin/thonzonium bromide otic

Brand names: Cortisporin-TC, Coly-Mycin S

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Suspension, otic [drops]:

Coly-Mycin S: Neomycin 0.33%, colistin 0.3%, hydrocortisone acetate 1%, and thonzonium bromide 0.05% (5 mL [DSC], 10 mL) [contains thimerosal]

Cortisporin-TC: Neomycin 0.33%, colistin 0.3%, hydrocortisone acetate 1%, and thonzonium bromide 0.05% (10 mL) [contains thimerosal]


Mechanism of Action

Colistin: Penetrates and disrupts bacterial cell membrane.

Hydrocortisone: Decreases inflammation by suppression of migration of polymorphonuclear leukocytes and reversal of increased capillary permeability.

Neomycin: Interferes with bacterial protein synthesis by binding to 30S ribosomal subunits.

Thonzonium: Promotes tissue contact by dispersion and penetration of the cellular debris and exudate.

Use: Labeled Indications

Otic infections: Treatment of superficial bacterial infections of the external auditory canal (otitis media); treatment of infections of mastoidectomy and fenestration cavities


Hypersensitivity to neomycin, colistin, hydrocortisone, thonzonium, or any component of the formulation; cutaneous viral infection (eg, herpes simplex virus, varicella zoster virus) of the external auditory canal

Documentation of allergenic cross-reactivity for aminoglycosides and corticosteroids is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.

Dosage and Administration

Dosing: Adult

Otic infections: Otic: Instill 5 drops in affected ear(s) 3 or 4 times daily

Note: Duration of use should be limited to 10 days. Use calibrated dropper provided in packaging.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Otic infections: Children ≥1 year and Adolescents: Otic: Instill 4 drops in affected ear(s) 3 or 4 times daily

Note: Duration of use should be limited to 10 days. Use calibrated dropper provided in packaging.


For otic use only. Shake otic suspension well before using. Thoroughly cleanse external auditory canal and dry with a sterile cotton applicator. Patient should lie down with affected ear upward and medication instilled. This position should be maintained for 5 minutes to facilitate penetration of the drops. Repeat, if necessary, for the opposite ear. Alternatively, a cotton wick may be inserted into the canal and the cotton may be saturated with the suspension; keep wick moist by adding suspension every 4 hours. Replace wick at least once every 24 hours. Otic preparations should not be used when the integrity of the tympanic membrane is in question (AAP [Rosenfeld 2014]).


Store at 20°C to 25°C (68°F to 77°F).

Drug Interactions

There are no known significant interactions.

Adverse Reactions

Frequency not defined.

Dermatologic: Skin irritation

Hypersensitivity: Local hypersensitivity reaction

Otic: Ototoxicity (rare)


Concerns related to adverse effects:

  • Adrenal suppression: Systemic absorption of topical corticosteroids may cause hypercortisolism or suppression of hypothalamic-pituitary-adrenal (HPA) axis, particularly in younger children or in patients receiving high doses for prolonged periods. HPA axis suppression may lead to adrenal crisis.
  • Immunosuppression: Prolonged use of corticosteroids may also increase the incidence of secondary infection, mask acute infection (including fungal infections), prolong or exacerbate viral infections, or limit response to vaccines.
  • Kaposi sarcoma: Prolonged treatment with corticosteroids has been associated with the development of Kaposi sarcoma (case reports); if noted, discontinuation of therapy should be considered (Goedert 2012).
  • Neomycin sensitization: Neomycin may cause cutaneous sensitization (primarily skin rash). Symptoms of neomycin sensitization include itching, low-grade reddening with swelling, dry scaling, itching, and failure to heal. Discontinue immediately if sensitization or irritation occurs.
  • Ototoxicity: Neomycin may cause permanent sensorineural hearing loss due to cochlear damage. Risk of ototoxicity is increased in patients with extended use; limit therapy to 10 days. Do not use in any patient with a perforated tympanic membrane.
  • Systemic effects: Topical corticosteroids may be absorbed percutaneously. Absorption of topical corticosteroids may cause manifestations of Cushing syndrome, hyperglycemia, or glycosuria. Absorption is increased by the use of occlusive dressings, application to denuded skin, or application to large surface areas.

Special populations:

  • Pediatric: Children may absorb proportionally larger amounts of corticosteroids after topical application and may be more prone to systemic effects. HPA axis suppression, intracranial hypertension, and Cushing syndrome have been reported in children receiving topical corticosteroids. Prolonged use may affect growth velocity; growth should be routinely monitored in pediatric patients.

Other warnings/precautions:

  • Appropriate use: For otic use only; do not use in the eyes. If infection is not improved after 1 week, preform cultures and susceptibility tests. Avoid contaminating the bottle tip with material from the ear, fingers, or other source.

Monitoring Parameters

Neomycin sensitization (eg, low-grade reddening with swelling, dry scaling, itching, failure to heal)


Pregnancy Risk Factor


Pregnancy Considerations

Animal reproduction studies have not been conducted with this combination. Refer to the individual Neomycin and Hydrocortisone monographs for additional information.

Patient Education

  • Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
  • Patient may experience burning or stinging. Have patient report immediately to prescriber ear irritation, unable to pass urine, change in amount of urine passed, or trouble hearing (HCAHPS).
  • Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Source: Wolters Kluwer Health. Last updated October 28, 2019.