Miconazole !

Imidazole antifungal used on the skin, in the vagina and on the gums for Candida and tinea. Even vaginal use can raise warfarin's effect.

Updated 2026-11-01

Class: Azole antifungals
Enzyme: Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme)
ATC code: G01AF04
WHO Model List of Essential Medicines

Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme)Miconazole

The figure shows clotrimazole, a closely related imidazole, bound to CYP51 of Acanthamoeba castellanii; miconazole occupies the same site of the sterol demethylase.

Target in 3D: Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme). PDB structure 6UW2 (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Miconazole, like other imidazoles, inhibits fungal sterol 14α-demethylase, so ergosterol is lacking and the membrane works poorly. It penetrates the outer layer of the skin well and acts locally.

Miconazole blocks the fungal sterol demethylase
Ergosterol falls and the membrane fails
Yeasts and dermatophytes stop growing on skin and mucosa

Pharmacokinetics

Absorption: Small from skin and vagina, but enough for interactions with warfarin.
Distribution: Readily penetrates the stratum corneum and persists there.

Indications

Vaginal yeast infection (vaginal cream or inserts). Vulvovaginal candidiasis →
Tinea corporis, tinea cruris and tinea pedis (topical). Dermatophytosis (tinea) and onychomycosis →
Cutaneous candidiasis (topical). Cutaneous and mucocutaneous candidiasis →
Oropharyngeal candidiasis (buccal tablet applied to the gum). Candidiasis: oral, oesophageal and invasive →

Adverse effects

Common

Vaginal burning, itching or irritation
Irritation or burning of the skin where applied

Contraindications

Hypersensitivity to miconazole
Self-treatment of a first vaginal yeast infection that was never diagnosed by a doctor

Key interactions

Warfarin: Bleeding or bruising may occur, even with vaginal products; the INR is checked.
Latex condoms and diaphragms: Vaginal miconazole can damage them, so they may fail.
Spermicides and tampons: Spermicides may interfere and tampons remove part of the drug; they are avoided during vaginal treatment.

What is monitored

Symptom response; recurrence of vaginal infection
INR in patients on warfarin

Administration and safety

Ask about warfarin before any miconazole product, including vaginal and oral gel or buccal forms.
Vaginal inserts or cream at bedtime; use sanitary pads, not tampons, during treatment.
Warn that latex condoms and diaphragms may fail during vaginal treatment.

Nursing care

Fever, chills, lower abdominal, back or shoulder pain, foul-smelling discharge or a missed period are not caused by yeast infection: they need medical review (STI, ectopic pregnancy).
Recurrent infections deserve a look for diabetes, antibiotics, steroids or HIV.
Teach patients on warfarin to report bruising or bleeding.

Pregnancy and breastfeeding

Pregnant women ask a health professional before using vaginal products; topical imidazoles are considered safe in pregnancy.

Test yourself

Think of the answer, then tap the question to see it.

A woman on warfarin buys vaginal miconazole over the counter. What is the risk?

Enough miconazole is absorbed to increase warfarin's effect: bleeding or bruising may occur; the INR should be checked.

Which symptoms suggest that vaginal discharge is not a yeast infection?

Fever, chills, lower abdominal pain, foul-smelling discharge or a missed period.

Why are tampons avoided during vaginal miconazole treatment?

They absorb and remove part of the drug from the vagina.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - MICONAZOLE 1- miconazole nitrate kit (DailyMed (U.S. National Library of Medicine), 2026); Miconazole Vaginal: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2023); Miconazole Topical: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2018); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 61 (McGraw Hill, 2023).

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Representative model, for educational purposes only.