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[Pharmacology](https://durgical.com/en/pharmacology/) · [Other antifungals](https://durgical.com/en/pharmacology/classes/other-antifungals/)

# Griseofulvin

Oral antifungal for dermatophytes of skin, hair and nails, classic for tinea capitis in children. It binds microtubules and is deposited in new keratin.

Updated 2026-11-01

- Class: [Other antifungals](https://durgical.com/en/pharmacology/classes/other-antifungals/)
- Target: Fungal microtubules (tubulin)
- ATC code: D01BA01
- WHO Model List of Essential Medicines

Also called: microsize griseofulvin, ultramicrosize griseofulvin

## Mechanism of action

Griseofulvin binds microtubule proteins needed for mitosis and disrupts the mitotic spindle, so the dermatophyte cannot divide. It is deposited in keratin precursor cells and binds tightly to new keratin, which then resists fungal invasion; the infected tissue is gradually replaced.

- Griseofulvin binds fungal microtubule proteins
- The mitotic spindle fails and the fungus cannot divide
- New keratin carries the drug and resists infection

## Pharmacokinetics

**Absorption**
Variable between people because it dissolves poorly; absorption improves with a fatty meal and with micro- or ultramicrosize forms.

**Distribution**
Concentrates in keratin precursor cells of skin, hair and nails.

**Metabolism**
Liver, mainly to 6-desmethylgriseofulvin; it induces liver enzymes.

**Half-life**
Variable, about 9 to 24 hours.

## Indications

- Dermatophyte infections of skin, hair and nails not adequately treated topically: tinea capitis, corporis, pedis, cruris, barbae and unguium. [Dermatophytosis (tinea) and onychomycosis →](https://durgical.com/en/conditions/dermatophytosis-and-onychomycosis/)

## Adverse effects

### Common

- Skin rash and urticaria (the most common reactions)
- Nausea, vomiting, epigastric discomfort, diarrhoea
- Headache, fatigue, dizziness, insomnia, confusion
- Photosensitivity; oral thrush

### Serious (rare, important)

- Peripheral neuropathy and paraesthesias
- Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme
- Hepatotoxicity with jaundice
- Lupus erythematosus or lupus-like syndromes

## Contraindications

- Porphyria
- Hepatocellular failure
- Pregnancy or possible pregnancy during treatment
- Hypersensitivity to griseofulvin

## Key interactions

**Warfarin-type anticoagulants**
Griseofulvin decreases their effect; the anticoagulant may need adjustment during and after treatment.

**Oestrogen-containing oral contraceptives**
Reduced contraceptive effect and menstrual irregularities; a second method is advised.

**Cyclosporine**
Lower cyclosporine levels and effect.

**Barbiturates**
Lower griseofulvin levels.

**Alcohol**
Nausea, vomiting, flushing, tachycardia and severe hypotension have been reported.

## What is monitored

- Periodic kidney, liver and blood-count tests with prolonged therapy
- Skin reactions and sun sensitivity

## Administration and safety

- Identify the dermatophyte (KOH, culture or nail biopsy) before starting.
- Microsize and ultramicrosize products are not dosed the same: check the exact product.
- Giving it with a fatty meal improves absorption.

## Nursing care

- Rule out pregnancy and teach a second contraceptive method during treatment.
- Teach to avoid intense sunlight and alcohol.
- Report rash, blistering, jaundice or joint pain.
- Men should wait at least six months after the course before fathering a child.

## Pregnancy and breastfeeding

Contraindicated: it is teratogenic in animals and cases of conjoined twins have been reported after first-trimester use.

## Memory aid

«GRISEOfulvin GRIPS keratin»: it rides into new keratin, stops fungal mitosis, and induces CYPs (less warfarin, less pill).

## Test yourself

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

## What is griseofulvin's mechanism of action?

It binds microtubule proteins and disrupts the mitotic spindle of the dermatophyte.

## A teenager on griseofulvin uses an oral contraceptive. What advice follows from the label?

Griseofulvin can reduce the pill's effectiveness; a second birth control method is advised, and pregnancy is a contraindication.

## Does griseofulvin treat candidiasis?

No. It acts only on dermatophytes; it is not effective against Candida, histoplasmosis or sporotrichosis.

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## Related drugs

- [Terbinafine](https://durgical.com/en/pharmacology/terbinafine/)
- [Itraconazole](https://durgical.com/en/pharmacology/itraconazole/)

## Related conditions

- [Dermatophytosis (tinea) and onychomycosis](https://durgical.com/en/conditions/dermatophytosis-and-onychomycosis/)

[← Back to the class: Other antifungals](https://durgical.com/en/pharmacology/classes/other-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: [DailyMed - GRISEOFULVIN MICROSIZE- griseofulvin tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1c26d7a6-17d9-4a95-a4ee-cfc5fe6bb95d) (DailyMed (U.S. National Library of Medicine), 2025); [Griseofulvin: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682295.html) (MedlinePlus (U.S. National Library of Medicine), 2017); 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.

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