ACETASOL HC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ACETASOL HC (ACETASOL HC).
Acetic acid (otic solution) is antibacterial and antifungal; hydrocortisone is a corticosteroid that suppresses inflammation.
| Metabolism | Not extensively metabolized; undergoes minimal hepatic metabolism. |
| Excretion | Acetasol HC is a combination product containing hydrocortisone and acetic acid. Hydrocortisone is primarily metabolized in the liver and excreted renally as inactive metabolites; less than 1% is excreted unchanged. Acetic acid is rapidly metabolized via the tricarboxylic acid cycle and eliminated as carbon dioxide and water. Biliary/fecal elimination is negligible for both components. |
| Half-life | Hydrocortisone has a terminal elimination half-life of approximately 1.5-2 hours. Acetic acid has a half-life of minutes due to rapid metabolism. Clinical context: dosing interval is typically 3-4 times daily for otic use. |
| Protein binding | Hydrocortisone is approximately 90-95% bound to corticosteroid-binding globulin (CBG) and albumin. Acetic acid has negligible protein binding (<10%). |
| Volume of Distribution | Hydrocortisone Vd is approximately 0.3-0.5 L/kg, indicating distribution into total body water. Acetic acid Vd is approximately 0.4 L/kg. Clinical meaning: limited tissue distribution; primarily remains in extracellular fluid. |
| Bioavailability | Otic: Bioavailability is approximately 10-20% via the ear canal due to slow permeation through tympanic membrane; systemic absorption is minimal (<10% of applied dose). Oral: Not applicable; product is for otic use only. |
| Onset of Action | Otic: Onset of anti-inflammatory effect occurs within 24 hours after instillation; peak effect may require 2-3 days. |
| Duration of Action | Otic: Duration of anti-inflammatory effect is typically 4-6 hours, necessitating multiple daily doses. Clinical note: Continue for 3-5 days after infection clears. |
5 drops into the affected ear(s) 3-4 times daily. Each drop contains 2% acetic acid and 1% hydrocortisone.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No renal adjustment required as systemic absorption is negligible. |
| Liver impairment | No hepatic adjustment required as systemic absorption is negligible. |
| Pediatric use | Same as adult: 5 drops into affected ear(s) 3-4 times daily. Safety and efficacy in children under 2 years not established. |
| Geriatric use | No specific adjustment; use same adult dosing. Consider age-related skin thinning and potential for increased systemic absorption in cases of tympanic membrane perforation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ACETASOL HC (ACETASOL HC).
| Breastfeeding | Systemic absorption after otic application is minimal. It is not known whether hydrocortisone or acetic acid is excreted in human milk. M/P ratio is not available. Concentrations in milk are likely negligible. Use is considered compatible with breastfeeding. |
| Teratogenic Risk | ACETASOL HC (hydrocortisone 1% and acetic acid 2%) is an otic solution. Systemic absorption following topical otic application is minimal. No adequate and well-controlled studies in pregnant women. Animal reproduction studies with topical glucocorticoids have shown an increased risk of cleft palate and other malformations at high doses. Based on limited human data and low systemic exposure, use during pregnancy is generally considered low risk. However, as a precaution, avoid use in the first trimester unless clearly needed. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to any component","Perforated tympanic membrane","Viral or fungal infections of the ear (except when used for fungal infections as indicated)"]
| Precautions | ["For otic use only; not for ophthalmic use","Prolonged use may result in overgrowth of non-susceptible organisms","Discontinue if sensitization or irritation occurs","Caution in patients with perforated tympanic membrane"] |
| Food/Dietary | No known food interactions. Avoid excessive alcohol as it may impair immune response. |
| Clinical Pearls |
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| Fetal Monitoring | No specific monitoring beyond routine pregnancy follow-up is required due to minimal systemic absorption. If used extensively on disrupted tympanic membrane, monitor for signs of systemic corticosteroid effects (unlikely). |
| Fertility Effects | No known effects on fertility based on limited systemic exposure. Animal studies with topical glucocorticoids at high doses have shown some reproductive effects, but these are not relevant for otic use. |
| ACETASOL HC (acetic acid 2%, hydrocortisone 1%) is used for otitis externa. Acetic acid restores acidic pH of ear canal, inhibiting bacterial and fungal growth. Hydrocortisone reduces inflammation and pruritus. Ensure tympanic membrane is intact before use due to risk of ototoxicity with corticosteroids in middle ear. Do not use for more than 7 days. Shake well before instillation. |
| Patient Advice | Instill 3-4 drops into affected ear every 2-3 hours for 5-7 days. · Lie on side for 5 minutes after instillation to ensure coverage. · Avoid inserting cotton swabs or objects into the ear. · Discontinue if pain, worsening discharge, or rash occurs. · Do not use if ear drum is perforated or if you have a history of ear surgery. |