Acetic Acid 2% (Ear Drops)

How it works

Acetic acid lowers the pH of the ear canal, creating an acidic environment that inhibits the growth of bacteria and fungi commonly responsible for otitis externa.

Prescribing in practice

• It should not be used if the eardrum is known or suspected to be perforated, and treatment should be reviewed if symptoms do not improve, to reconsider the diagnosis.
• It may cause transient stinging or burning in the ear on application.
• It is intended for short-term topical use in the external ear canal only.

Monitoring

Review clinical response over the course of treatment and reassess if symptoms persist, worsen, or fail to settle within the expected period.

Counselling the patient

• Use the drops in the affected ear as directed and avoid getting water in the ear.
• A brief stinging sensation after putting the drops in is common and usually settles.
• See your clinician if the ear does not improve, becomes more painful, or starts to discharge.

Evidence & guidelines

Topical acidifying preparations are a long-established treatment for otitis externa, supported by clinical practice and guidance for ear canal infections.