Grifulvin

Indications

Griseofulvin is an antifungal medicine taken by mouth for ringworm-type (dermatophyte) fungal infections of the scalp, skin, hair and nails, when creams alone are not enough. It is commonly used for scalp ringworm (tinea capitis), widespread skin ringworm and fungal nail infections. It does not work against yeast infections such as thrush.

How It Works

Griseofulvin builds up in the new skin, hair and nail cells as they grow. It stops the fungus from dividing, so the infected tissue is gradually replaced by healthy, fungus-free tissue. This is why treatment takes several weeks or months.

Dosage and Administration

• Adults: usually 500 mg a day, as a single dose or divided doses. For severe infections the doctor may prescribe up to 1 g a day, reducing to 500 mg once there is improvement.
• Children: dose depends on body weight, as prescribed.
• Take it with or after a meal, preferably one containing some fat, which helps absorption.
• Usual length of treatment: skin about 2 to 4 weeks, scalp about 6 to 8 weeks or longer, fingernails at least 6 months, toenails 12 months or more.

Keep taking it for the full course, even when the infection looks better, or it may come back.

Interactions

• Birth control pills: Griseofulvin can make them less effective; use an extra method such as condoms during treatment and for 1 month after.
• Warfarin: its effect may be reduced; clotting tests may need checking.
• Phenobarbital: lowers Griseofulvin levels.
• Ciclosporin: levels may be reduced.
• Alcohol: may cause flushing and a fast heartbeat; avoid alcohol.

Contraindications

• Allergy to griseofulvin or any ingredient of the product.
• Pregnancy, or planning a pregnancy.
• Severe liver disease.
• Porphyria (a rare inherited blood disorder).
• Systemic lupus erythematosus (SLE).

Side Effects

Common: headache, nausea, vomiting, diarrhoea, stomach upset, rash and dizziness. Others: tiredness, confusion, sensitivity to sunlight, taste changes, and rarely numbness or tingling. Rarely it can affect the liver or lower white blood cell counts.

Get urgent medical help if you have a severe skin reaction (blistering, peeling, widespread rash or mouth sores), yellow skin or eyes, dark urine, fever, sore throat or mouth ulcers that do not go away, or signs of a serious allergic reaction such as swelling of the face or difficulty breathing.

Pregnancy and Lactation

Must not be used during pregnancy, as it may harm the unborn baby. Women should avoid becoming pregnant during treatment and for at least 1 month after. Men should not father a child during treatment and for at least 6 months after. Avoid during breastfeeding.

Precautions and Warnings

Avoid strong sunlight and sunbeds and use sun protection. It may cause dizziness, so take care when driving. For long courses, the doctor may check blood counts and liver function. Keep the infected areas clean and dry, and do not share combs, towels or hats.

Overdose

Too much may cause headache, nausea, vomiting, diarrhoea, tiredness and confusion. Seek medical help.

Therapeutic Class

Antifungal (oral, for dermatophyte infections).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.