Vetdrugs 2.0Clotrimazole is an imidazole antifungal used locally against susceptible yeasts and other fungi. Veterinary applications include Malassezia otitis, localized superficial fungal disease and specialist treatment of canine sinonasal aspergillosis. Many otic products combine it with an antibacterial and a glucocorticoid, each contributing a separate component of treatment.
Group
Imidazole antifungal
Mechanism of Action
Clotrimazole inhibits fungal lanosterol 14-alpha-demethylase, reducing synthesis of ergosterol needed for normal cell-membrane structure. Altered sterol composition impairs membrane permeability and membrane-associated enzyme function, suppressing or killing susceptible fungi. Local delivery produces exposure at infected skin, ear or sinonasal surfaces. Antibacterial and anti-inflammatory effects of combination products arise from their other ingredients.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Otitis externa | Reference only | TOPICAL | Every 24 h | Up to 7 days; Mometamax small bottles (7.5, 15 or 30 g): dogs under 30 lb receive 4 drops per affected ear; dogs at least 30 lb receive 8 drops. The 215 g bottle delivers a different drop size: 2 or 4 drops respectively. Once daily for 7 days. |
| Sinonasal aspergillosis | Reference only | IN | Specialist local treatment: published short protocol uses 1% clotrimazole solution flushing for 5 minutes followed by a 1% cream sinus depot; treatment volume and technique are individualized. | |
| Localized superficial yeast dermatitis | Reference only | TOPICAL | Every 12 h | Single-active clotrimazole spray is generally applied twice daily; ointment may be used up to four times daily depending on the actual formulation. Avoid eyes and mucous membranes. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Localized superficial yeast dermatitis | Reference only | TOPICAL | Every 12 h | Single-active clotrimazole spray is generally applied twice daily; ointment may be used up to four times daily depending on the actual formulation. Avoid eyes and mucous membranes. |
Indications
- Treatment of Malassezia-associated otitis externa in dogs using a suitable clotrimazole-containing otic product.
- Local treatment of selected susceptible superficial yeast or dermatophyte infections.
- Specialist local treatment of canine sinonasal aspergillosis within a supported debridement and antifungal treatment protocol.
Contraindications
- Formulation hypersensitivity
- Otic combination use through a ruptured tympanic membrane
Interactions
- Ototoxic medicines increase risk with aminoglycoside-containing ear combinations.
Adverse effects
- Local irritation
- Combination-dependent ototoxicity or corticosteroid effects
Toxicity
Inappropriate local formulations or delivery techniques may injure mucosa or expose the central nervous system.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Mometamax otic suspension All strengths per gram; gentamicin and mometasone furoate equivalents are supplied as sulfate and monohydrate respectively. Shake; clean and dry ear; verify intact eardrum. Drop count depends on bottle size. Store 2–25°C; use within 28 days of opening. | Other | clotrimazole 10 mg / g + gentamicin 3 mg / g + mometasone furoate 1 mg / g | TOPICAL |
| Otomax gentamicin/betamethasone/clotrimazole ointment All strengths per gram; betamethasone supplied as valerate. Otic product, also described for selected extralabel skin uses. Follow this product’s schedule, not Mometamax’s drop count. | Other | clotrimazole 10 mg / g + gentamicin 3 mg / g + betamethasone 1 mg / g | TOPICAL |
Monitoring and Administration
Diagnose otitis by examination and cytology and inspect the tympanic membrane before treatment.
Sinonasal treatment requires imaging, debridement and protected-airway delivery. Published protocols include 1% solution irrigation followed by a 1% cream depot; technique and volume cannot be replaced by a generic mg/kg calculation.
Topical clotrimazole alone is often ineffective for feline dermatophytosis; do not assume a localized Malassezia regimen will cure generalized ringworm.
Otic combinations with gentamicin and betamethasone or mometasone may be used on selected inflamed bacterial/yeast skin lesions in an extralabel plan. Prevent licking for 20–30 minutes and monitor steroid-associated atrophy or adrenal effects.
Topical corticosteroids may affect allergy testing; a two-week washout has been suggested, subject to the testing protocol.