Griseofulvin

Key facts

• Griseofulvin is an oral antifungal that treats dermatophyte (ringworm-type) infections of the skin, scalp, hair and nails when creams alone cannot reach the fungus.
• It is taken with a fatty meal, which increases absorption, and courses often run for several weeks to months depending on the site of infection.
• Griseofulvin is teratogenic and must not be used in pregnancy. Women should avoid pregnancy during treatment and for one month after, and men are advised to avoid fathering a child for six months after treatment. It also makes hormonal contraceptives less effective.
• Seek urgent care for yellowing of the skin or eyes, severe skin blistering, or signs of an allergic reaction.

What griseofulvin treats

Griseofulvin treats dermatophyte fungal infections of the skin (tinea corporis), scalp (tinea capitis), and nails (onychomycosis) when the infection is extensive or has not cleared with topical antifungal treatment alone. It does not treat yeast infections such as candida or non-dermatophyte causes of athlete's foot.

How griseofulvin works

Griseofulvin is absorbed into the bloodstream and concentrates in keratin, the protein that makes up skin, hair and nails. There it disrupts the fungal cell's internal skeleton (microtubules), stopping the fungus from dividing. As new keratin grows in fungus-free, the infection is gradually replaced and shed.

Before you take it

• Do not take griseofulvin if you are pregnant, or if you have severe liver disease, porphyria, or a known allergy to it.
• Tell your prescriber if you or your partner are planning a pregnancy; effective contraception is essential during and after treatment, and griseofulvin reduces the reliability of hormonal contraceptives, so a non-hormonal method should be added.
• Avoid alcohol, which can cause flushing, a fast heartbeat and nausea when combined with griseofulvin.

Side effects

Common effects include headache, nausea, loss of appetite and increased sensitivity to sunlight.

Stop and seek urgent medical care for:

• Yellowing of the skin or eyes, dark urine, or persistent nausea (possible liver problems).
• Severe skin blistering or peeling.
• Signs of an allergic reaction such as rash, swelling or difficulty breathing.

Safety essentials

• Griseofulvin is teratogenic. Confirm you are not pregnant before starting, use effective contraception (including a non-hormonal method, since griseofulvin weakens hormonal contraceptives) throughout treatment, and continue contraception for one month after stopping. Men should avoid fathering a child for six months after treatment ends.
• Wear sun protection, since griseofulvin increases the skin's sensitivity to sunlight and sunburn risk.
• Blood tests to check liver function are used for courses longer than a few weeks; report unusual tiredness, dark urine or yellowing skin promptly.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.