HYDROCORTISONE AND ACETIC ACID
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.
Hydrocortisone is a corticosteroid that binds to the glucocorticoid receptor, leading to increased lipocortin synthesis, inhibition of phospholipase A2, decreased arachidonic acid release, and reduced prostaglandin and leukotriene production; it also suppresses cytokine expression and immune cell migration. Acetic acid is a weak acid that lowers local pH, inhibiting bacterial and fungal growth and disrupting microbial cell membranes.
| Metabolism | Hydrocortisone undergoes hepatic metabolism primarily via CYP3A4 to inactive metabolites; acetic acid is metabolized via the Krebs cycle to carbon dioxide and water. |
| Excretion | Renal: ~60-70% as metabolites; biliary/fecal: ~10-15%; unchanged drug: <5%. |
| Half-life | Plasma t1/2: 1.5-2 hours; biological t1/2: 8-12 hours (based on HPA axis suppression). |
| Protein binding | Hydrocortisone: ~90-95% (corticosteroid-binding globulin and albumin). |
| Volume of Distribution | Vd: 0.3-0.5 L/kg; reflects distribution into total body water. |
| Bioavailability | Otic suspension: approximately 100% locally; oral: 20-25% (due to first-pass metabolism); IV: 100%. |
| Onset of Action | Topical otic: 30 minutes to 1 hour; systemic (IV): rapid (minutes). |
| Duration of Action | Topical otic: 6-8 hours per application (otitis externa relief). Systemic duration: 12-24 hours (anti-inflammatory). |
Instill 5 drops into affected ear(s) twice daily for 7-10 days; or as directed by physician.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dose adjustment required for topical otic use; systemic absorption negligible. |
| Liver impairment | No dose adjustment required for topical otic use; systemic absorption negligible. |
| Pediatric use | Instill 3-5 drops into affected ear(s) twice daily for 7-10 days; for children ≥2 years, same as adult; for <2 years, use only under physician guidance. |
| Geriatric use | No specific adjustment; use same as adult dose. Monitor for local irritation or superinfection. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
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 |
| Breastfeeding | Hydrocortisone: Excreted in breast milk in small amounts; unlikely to cause adverse effects. M/P ratio not well defined for topical/otic use. Acetic acid: No data. Use with caution; apply minimal amounts. |
| Teratogenic Risk | Hydrocortisone: Corticosteroids are associated with increased risk of cleft palate (first trimester) and fetal growth restriction (chronic use). Acetic acid: No known teratogenic risk; limited data. Overall: Use only if benefit outweighs risk, minimal systemic absorption from topical/otic application. |
■ FDA Black Box Warning
None
| Common Effects | Injection site reactions pain swelling redness Mood changes Increased risk of infection Weight gain |
| Serious Effects |
["Hypersensitivity to hydrocortisone, acetic acid, or any component of the formulation","Viral infections of the external ear (e.g., herpes simplex)","Fungal infections of the external ear","Perforated tympanic membrane (relative contraindication for acetic acid component)"]
| Precautions | ["Prolonged use may lead to secondary infections, ototoxicity, or perforation of tympanic membrane; avoid in patients with viral or fungal infections of the ear; discontinue if irritation or sensitization develops; use with caution in patients with perforated eardrum."] |
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| Fetal Monitoring | Monitor for maternal adrenal suppression with prolonged use; fetal growth and development if used extensively. |
| Fertility Effects | No known adverse effects on fertility at typical doses. |