Topical antibacterial / Antifungal (ear) Pregnancy: Safe for topical use in pregnancy.

Acetic Acid 2% (Ear Drops)

Brand names: EarCalm, Otomize (with neomycin/dexamethasone)

Adult dose

Dose: 2–4 drops instilled into affected ear 3–4 times daily for 7 days

Route: Otic (ear drops)

Frequency: 3–4 times daily

Max: 6 drops per instillation

Otitis externa (swimmer's ear): 2% acetic acid 4 drops QDS for 7 days. EarCalm: licensed OTC. Can use ear wick if canal swollen to facilitate delivery. Warm drops to body temperature to reduce dizziness.

Paediatric dose

Route: Otic

Frequency: 3–4 times daily

Max: 4 drops per instillation

Children ≥12 years: adult dose. <12 years: specialist guidance; generally 2–3 drops TDS. Ensure tympanic membrane is intact before using any ear drops.

Dose adjustments

Renal

No systemic adjustment (topical).

Hepatic

No systemic adjustment (topical).

Clinical pearls

First-line for uncomplicated otitis externa in NICE and SIGN guidelines
Ensure TM is intact before prescribing any ear drops
Lie down with affected ear uppermost — maintain position 2–3 minutes after instillation
Aural toilet (microsuction) by trained clinician improves outcomes
If canal very swollen: ear wick (Pope wick/ear tampon) for 24–48 hours to allow drops in
Avoid cotton bud use — traumatises canal and disrupts cerumen

Contraindications

Perforated tympanic membrane
Grommets (tympanostomy tubes) — unless specifically ototopical-safe drops prescribed
Hypersensitivity

Side effects

Mild burning and stinging on application
Ototoxicity risk if tympanic membrane perforated (especially aminoglycoside combinations)

Interactions

No significant systemic interactions

Monitoring

Clinical response at 1 week
Signs of spread (cellulitis, malignant OE in diabetics/immunocompromised)

Reference: BNFc; BNF; NICE NG91 Otitis Externa; SIGN 66. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways