Griseofulvin is an oral antifungal antibiotic derived from Penicillium griseofulvum. It is fungistatic and specifically targets dermatophyte infections of the skin, hair, and nails by disrupting fungal cell division. It is a cornerstone treatment for tinea infections in India, though newer antifungals are often preferred due to its side effect profile and long treatment duration.
Adult: 250mg to 500mg once daily or in divided doses. For fingernails: 500mg daily for 4-6 months. For toenails: 500mg daily for 6-12 months.
Note: Must be taken with or immediately after a high-fat meal (e.g., milk, peanut butter, full-fat yogurt) to significantly enhance absorption. Tablets should be swallowed whole, not crushed or chewed.
Griseofulvin binds to polymerized microtubules within fungal cells, specifically to tubulin. This disrupts the mitotic spindle by interfering with microtubule function during metaphase, arresting cell division at the metaphase stage. It also disrupts the fungal cell wall synthesis by impairing the deposition of chitin.
Pregnancy: Category C (US FDA). Teratogenic and embryotoxic in animal studies. Contraindicated in pregnancy. Effective contraception required during and for 1 month after treatment in women of childbearing potential.
Driving: May cause dizziness, headache, or fatigue. Caution advised when driving or operating machinery until response is known.
| Warfarin | Griseofulvin reduces anticoagulant effect by enzyme induction; increased warfarin dose may be needed. | Major |
| Oral Contraceptives | Reduces efficacy, leading to breakthrough bleeding and contraceptive failure. | Major |
| Cyclosporine | Reduces cyclosporine levels, risking transplant rejection. | Major |
| Phenobarbital | Reduces griseofulvin levels via enzyme induction, decreasing antifungal efficacy. | Moderate |
| Alcohol | May cause disulfiram-like reaction (flushing, tachycardia, nausea). | Moderate |
Same composition (Griseofulvin (250mg)), different brands: