Osurnia Ear Gel for Dogs: Complete Guide – How the 2-Dose Protocol Works, What It Treats, the 45-Day No-Cleaning Rule & How It Compares to Surolan and Easotic

Osurnia is unlike any other ear drop product in veterinary medicine. While Surolan, Easotic, and Otomax require owners to apply drops twice daily for 5–7 days at home, Osurnia delivers the entire treatment course in just two gel applications given in the vet clinic, one week apart. Understanding why it works this way — and the strict rules around ear cleaning — is essential for getting the best results.

What Is Osurnia?

Osurnia is a veterinary otic gel manufactured by Dechra Animal Health, containing three active substances per ml:

• Florfenicol 10mg/ml — broad-spectrum bacteriostatic antibiotic
• Terbinafine 10mg/ml — allylamine antifungal with fungicidal activity
• Betamethasone acetate 1mg/ml — potent glucocorticosteroid anti-inflammatory

Each treatment application uses one 1ml single-use tube per affected ear. The complete course is two doses, seven days apart. For dogs with both ears affected, that is four tubes total across two vet visits — no owner-administered daily treatment in between.

The Gel Mechanism: Why Two Doses Is Enough

This is the fundamental innovation that separates Osurnia from conventional ear drops. When conventional drops (water- or oil-based solutions) are instilled into the ear canal, they coat the ear wall briefly and then drain out — either into the horizontal canal, absorbed into tissue, or expelled when the dog shakes its head. Effective concentration at the infection site is short-lived, which is why conventional products must be applied every 12–24 hours.

Osurnia’s gel does something different:

• On contact with the warm ear canal, the gel coats the entire canal surface and adheres — including the curved horizontal canal that liquid drops often fail to fully coat
• The gel is designed to dissolve slowly in ear wax, releasing active substances gradually as the ear’s natural self-cleaning process moves wax outward over approximately 2–3 weeks
• This sustained release maintains therapeutic concentrations of florfenicol, terbinafine, and betamethasone at the infection site continuously, without any further owner application

The second dose at day 7 reinforces and extends this sustained exposure for a total of approximately six weeks of continuous therapy from just two applications.

What Osurnia Treats — And What It Doesn’t

Indicated for:

• Acute otitis externa in dogs caused by susceptible Staphylococcus pseudintermedius (bacteria) and/or Malassezia pachydermatis (yeast)
• Acute exacerbation of recurrent otitis externa — flare-ups of a recurring condition

Not effective against:

• Pseudomonas aeruginosa — in the Osurnia field study, all three dogs where Pseudomonas was the sole pathogen were treatment failures. Florfenicol does not reliably cover Pseudomonas. If a culture shows Pseudomonas-dominated infection, Osurnia is the wrong choice — gentamicin-based products or culture-directed systemic/topical therapy is required.
• Ear mites (Otodectes cynotis) — a separate acaricidal treatment must be used if ear mites are the cause
• Otitis media (middle ear infection) — Osurnia is an external ear canal product only

The Three Active Ingredients — Why Each Matters

Florfenicol — A Different Antibiotic Class

Florfenicol is a bacteriostatic antibiotic structurally related to chloramphenicol, inhibiting protein synthesis by binding the bacterial 50S ribosome. Unlike gentamicin (the antibiotic in Easotic), florfenicol is not an aminoglycoside — it does not share the ototoxicity risk profile of aminoglycosides when the eardrum is intact. Its broad Gram-positive and Gram-negative spectrum covers Staphylococcus pseudintermedius effectively at the 10mg/ml topical concentration.

Terbinafine — The Azole-Alternative Antifungal

This is clinically significant. Surolan and Easotic both use miconazole as their antifungal — an azole that inhibits CYP51 (lanosterol 14α-demethylase) in the ergosterol biosynthesis pathway. Terbinafine takes a completely different approach: it inhibits squalene epoxidase, an enzyme earlier in the same pathway. Because the two drug classes act at different enzymes, there is no cross-resistance between terbinafine and azoles.

Practically, this matters for dogs with recurrent Malassezia otitis that has failed or repeatedly relapsed on azole-based treatments — terbinafine may retain full fungicidal activity against those same organisms. Terbinafine is also fungicidal (kills Malassezia) rather than merely fungistatic (inhibits its growth), giving it a theoretical efficacy advantage.

Betamethasone Acetate — Rapid Symptom Relief

Betamethasone acetate is a potent diester glucocorticosteroid — the same chemical class as the hydrocortisone aceponate in Easotic, but betamethasone has higher intrinsic glucocorticoid potency. It rapidly reduces the inflammation, oedema, and pruritus (itch) that make ear infections so uncomfortable. Most dogs show visible improvement in ear pain and head shaking within 24–48 hours of the first dose.

Systemic absorption is low at the recommended dose but not zero — low plasma concentrations are detectable mainly in the first 2–4 days after each application. This is why generalised demodicosis is a contraindication — the corticosteroid component may worsen widespread Demodex infestation.

The Complete Dosing Protocol

Two Doses. That’s It.

The 45-Day No-Cleaning Rule — Why It Exists

This is the most important instruction for owners and the most frequently violated one. After the first dose, the ear must not be cleaned for 45 days. Here is why:

• Ear cleaning physically removes gel from the canal
• When gel is removed, the drug reservoir is removed
• The sustained-release mechanism depends entirely on the gel remaining in contact with the canal wall
• Cleaning even once substantially reduces the drug contact time and compromises treatment

The 45-day period covers: the 7-day inter-dose window (dose 1 must remain in place until dose 2 is given), plus approximately 38 days for dose 2 to be gradually cleared by natural ear wax movement. After day 45+, normal ear hygiene can resume.

If the ear is accidentally cleaned within the 45-day period, contact your vet — a repeat dose may be required.

Critical Safety Warnings

Eardrum Integrity — Check Before Every Dose

Osurnia must never be used if the tympanic membrane is ruptured or suspected to be perforated. The vet must confirm eardrum integrity by otoscopic examination before each application. Tympanic rupture has been reported post-approval with Osurnia use — if any neurological signs develop (head tilt, balance loss, nystagmus, facial asymmetry, sudden deafness), discontinue immediately and seek emergency veterinary assessment.

Eye Protection — Mandatory

Wear eye protection during application. If the dog shakes its head immediately after instillation, gel splatter can reach human eyes and the dog’s eyes. Corneal ulcers have been reported in both humans and dogs following Osurnia administration. Anyone present during application should protect their eyes.

Do Not Use In:

• Cats
• Dogs with generalised demodicosis
• Dogs with perforated eardrums
• Pregnant or breeding animals
• Dogs under 2 months of age or under 1.4 kg

Osurnia vs Surolan vs Easotic vs Otomax

When Is Osurnia the Best Choice?

Osurnia is the strongest choice when:

• Owner compliance with daily drops is a known or anticipated problem
• The dog is aggressive or difficult to medicate at home
• The infection has relapsed after azole-based antifungal treatment (terbinafine’s different mechanism may succeed where miconazole failed)
• A clinic-controlled, protocol-driven treatment course is preferred

Consider alternatives when:

• Culture confirms Pseudomonas aeruginosa as the pathogen
• Generalised demodicosis is present (corticosteroid contraindication)
• The dog cannot make two clinic visits
• The eardrum cannot be confirmed intact

Where to Buy Osurnia

You can order Osurnia Otic Gel (Florfenicol + Terbinafine + Betamethasone) 1ml tubes from PetShopBoss.com with free worldwide shipping.

Related: Surolan 15ml (Miconazole + Polymyxin B + Prednisolone) | Easotic 10ml (Gentamicin + Miconazole + HCA) | Epiotic Ear Cleaner 60ml