Efinaconazole
Topical antifungals
Topical antifungals
Topical triazole solution for fungal toenail infection (onychomycosis); applied daily for about a year to the toenails only.
Quick facts
- Group
- Topical antifungals
- Target
- Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme)
- Used for
- Onychomycosis of the toenails
- Key effects
- Redness · Burning · Blisters
- Monitor
- Growth of clear nail over months
- ATC
- D01AC19
No doses: the clinician sets them by the current guideline.
Mechanism of action
Efinaconazole is a triazole made to penetrate the nail. Like other azoles it blocks fungal lanosterol 14α-demethylase (CYP51), so ergosterol is not made and the fungal membrane fails. The nail grows out slowly, so treatment lasts many months and the clear nail appears only as new nail replaces the infected part.
- The solution penetrates the nail plate to the nail bed
- The triazole blocks fungal CYP51
- Ergosterol is not made and the membrane fails
- Healthy nail grows out over many months
Indications
- Onychomycosis of the toenails by dermatophytes (Trichophyton rubrum, T. mentagrophytes) Dermatophytosis (tinea) and onychomycosis →
Adverse effects
- Redness, itching or swelling around the nail
- Burning, stinging or pain where applied
- Blisters
- Ingrown toenail
Contraindications
- Allergy to efinaconazole or any ingredient of the product
Key interactions
- Nail polish and cosmetic nail products
- Not used during treatment: they block the solution from reaching the nail.
- Heat and open flames
- The solution is flammable; it is kept away from fire while applying it.
What is monitored
- Growth of clear nail over months; reassess if no improvement
- Irritation or ingrown nails around the treated toes
Administration and safety
- Toenails only: not on other skin, and kept out of the eyes, nose, mouth and vagina
- Applied once a day to clean, dry nails, at about the same time each day
- Flammable: no smoking or flames nearby during application
- No pedicures or nail polish during treatment
Pregnancy and breastfeeding
Human data are lacking; pregnancy is discussed with a clinician before use.
Nursing care
- Explain that results take months and that the course should not be stopped early
- Teach to wait after washing until the nails are completely dry before applying
- Teach foot hygiene: dry between the toes, change socks, avoid walking barefoot in shared showers
- Report severe irritation, blisters or pain
Pharmacokinetics
- Absorption
- Applied to the toenails; designed for local action in the nail and nail bed.
Test yourself
Think of the answer, then tap the question to see it.
What is efinaconazole used for?
Fungal infection of the toenails (onychomycosis), mainly by dermatophytes.
Why does efinaconazole treatment last many months?
The infected nail must grow out and be replaced by healthy nail, which is slow.
Which safety point about the solution itself is taught to patients?
It is flammable, so it is kept away from heat and open flames during application.
Connections
← Back to the class: Topical antifungals
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Efinaconazole Topical: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.