(1997; 132 pages) [French] [Spanish]
Tablet or capsule, 125 mg, 250 mg, 500 mg
Oral suspension, 125 mg/ml
Griseofulvin is an antibiotic produced by Penicillium griseofulvum. It has selective fungistatic activity against the dermatophytes that cause ringworm (tinea) infections, but it has no activity against pityriasis (tinea) versicolor or Candida spp. It acts by disrupting the mitotic apparatus of fungal cells, thereby inhibiting protein synthesis.
Griseofulvin is efficiently absorbed after oral administration, particularly when taken with fatty foods. It has a plasma half-life of 24 hours and is extensively metabolized in the liver. About 50% is excreted in the urine, largely as metabolites, within 5 days. Much of the remainder is selectively bound in keratin precursor cells, particularly in infected areas.
Treatment of superficial fungal infections that are unresponsive to topical agents or that involve the scalp or nails. Griseofulvin is unsuitable for prophylactic use.
Dosage and administration
Griseofulvin should be administered preferably with, or immediately after, meals. All dosages are suitable for both adults and children.
Ringworm of the trunk, groin or foot:
10 mg/kg daily either as a single dose or in divided doses, up to a maximum total dose of 1 g, for 4 weeks.
In patients with associated infections of the nails treatment may need to be extended for 12-18 months. Close attention should also be given to personal hygiene.
10 mg/kg daily in two divided doses, up to a maximum total dose of 1 g, for at least 6 weeks. In severe cases treatment may need to be extended for up to 3 months. Topical application of an imidazole cream may accelerate clearing of scaly lesions.
• Known hypersensitivity to griseofulvin.
• Porphyria or systemic lupus erythematosus.
• Severe hepatic impairment.
Patients should be warned that the effects of alcohol may be potentiated during treatment and that their ability to drive and to operate machinery may be impaired.
Patients with hepatic insufficiency should receive the drug only under close medical supervision. Hepatic function should be monitored closely throughout treatment.
Leukopenia and albuminuria may occur.
Women of child-bearing age should take effective contraceptive precautions during treatment and for several weeks thereafter.
Use in pregnancy
Griseofulvin has been associated with fetotoxicity in animal models. It should not be administered during pregnancy.
Some patients complain of headache, which may be severe, particularly during the early phases of treatment, but this often regresses if treatment is continued. Nausea, vomiting, diarrhoea, fatigue, lethargy, dry mouth and perlèche are less common.
Reported hypersensitivity reactions include urticaria, photosensitivity, erythema multiforme, vesicular and morbilliform eruptions, serum sickness, angio-oedema and, rarely, precipitation of systemic lupus erythematosus. Other rare, but serious, effects include hepatic dysfunction, severe leukopenia, and neurological symptoms such as peripheral neuritis, confusion and blurred vision due to macular oedema.
Estrogen-like effects have been reported in children. Breakthrough bleeding, amenorrhoea and failure of contraceptive therapy have been reported in women using oral contraceptives.
Long-term administration at high dosage has been reported to induce hepatomas in mice and thyroid tumours in rats.
Griseofulvin may reduce the efficacy of coumarin anticoagulants and oral contraceptives, while concurrent administration of barbiturates may reduce the efficacy of griseofulvin. Barbiturates may also impair the absorption of griseofulvin.
Griseofulvin may exacerbate the side-effects of alcohol.
Treatment is symptomatic and supportive. No specific antidote exists.
Griseofulvin preparations should be stored in well-closed containers.