Miconazole
Miconazole is a broad-spectrum **imidazole antifungal** agent used primarily for the topical treatment of fungal skin and ear infections, including **dermatophytosis** (ringworm) and **Malassezia dermatitis**. It is frequently formulated in combination with other agents (such as chlorhexidine, corticosteroids, or antibiotics) to provide synergistic effects in treating otitis externa and pyoderma. > **Clinical Pearl:** While highly effective topically, miconazole is rarely used systemically in veterinary medicine due to potential toxicity and the availability of safer systemic alternatives like itraconazole or fluconazole.
Mechanism: Miconazole works by inhibiting the **cytochrome P450-dependent enzyme 14-alpha-demethylase** in fungal cells. Inhibition of 14-alpha-demethylase โ depletion of **ergosterol** (a vital component of the fungal cell membrane) โ accumulation of toxic sterol precursors โ increased cell wall permeability โ leakage of cellular contents and subsequent fungal cell death. It has potent activity against *Malassezia*, *Cryptococcus*, *Candida*, and *Coccidioides*.
Dosing by species
- Fungal otitis ยท 2-12 drops in affected ear ยท topical ยท q12-24h ยท Surolan formulation
- Fungal otitis ยท 1 ml per ear ยท topical ยท q24h ยท 5 days ยท Easotic formulation
- Fungal otitis ยท 5 drops in affected ear ยท topical ยท q12h ยท Aurimic formulation
- Dermatophytosis ยท Apply a thin layer of cream topically to affected area ยท topical ยท bid ยท Continue for 2 weeks after a clinical cure and negative fungal cultures ยท Daktarin formulation
- Malassezia dermatitis ยท Shampoo twice weekly until the clinical signs subside and weekly thereafter or as necessary ยท topical ยท twice weekly ยท Until clinical signs subside, then weekly ยท Malaseb, Adaxio formulations
- Small localized skin infections ยท Apply a few drops to affected skin ยท topical ยท q12h ยท Aurimic formulation
- Fungal otitis ยท 2-12 drops in affected ear ยท topical ยท q12-24h ยท Surolan formulation
- Fungal otitis ยท 1 ml per ear ยท topical ยท q24h ยท 5 days ยท Easotic formulation
- Fungal otitis ยท 5 drops in affected ear ยท topical ยท q12h ยท Aurimic formulation
- Dermatophytosis ยท Apply a thin layer of cream topically to affected area ยท topical ยท bid ยท Continue for 2 weeks after a clinical cure and negative fungal cultures ยท Daktarin formulation
Routes of administration
Contraindications
- Hypersensitivity to miconazole or other azole antifungals
- Ruptured tympanic membrane (for certain otic preparations)
Adverse effects
- Local irritation
- Erythema
- Pruritus (rare)
Monitoring
- Resolution of clinical signs (pruritus, erythema, scaling)
- Fungal cultures (for dermatophytosis)
- Cytology (for Malassezia)
Overdose
Overdose is highly unlikely with topical administration. Accidental ingestion of shampoos or creams may cause mild gastrointestinal upset (hypersalivation, vomiting, diarrhea). Treatment is symptomatic and supportive.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturerโs current label.