Griseofulvin is an oral antifungal antibiotic derived from Penicillium griseofulvum. It is fungistatic and specifically active against dermatophytes (Trichophyton, Microsporum, Epidermophyton). It is a cornerstone treatment for tinea infections of the skin, hair, and nails in India, where such superficial fungal infections are highly prevalent due to climatic conditions. It works by depositing in keratin precursor cells, making newly formed keratin resistant to fungal invasion.
Adult: 500mg to 1g daily, in single or divided doses. Standard for tinea corporis/cruris: 500mg once daily. For tinea capitis/onychomycosis: 500mg to 1g daily. Must be taken with or after a high-fat meal.
Note: Must be taken with or immediately after a meal, preferably a high-fat meal (e.g., milk, butter, nuts) to enhance absorption. Tablet should be swallowed whole with a full glass of water. Duration: Tinea corporis/cruris: 2-4 weeks. Tinea capitis: 4-6 weeks or more. Tinea unguium (fingernails): at least 4 months; (toenails): at least 6 months. Treatment should continue for at least 2 weeks after symptoms resolve and cultures are negative.
Griseofulvin disrupts the mitotic spindle by binding to polymerized microtubules. It inhibits fungal mitosis by interfering with microtubule function during metaphase, arresting cell division at the metaphase stage. It has no effect on other stages of the fungal cell cycle or on human cell division at therapeutic doses.
Pregnancy: US FDA Pregnancy Category C. Animal studies show teratogenic and embryotoxic effects. Contraindicated in pregnancy. Effective contraception required during and for 1 month after treatment in women of childbearing potential.
Driving: May cause dizziness, headache, and blurred vision. Patients should be cautioned about driving or operating machinery until their response is known.
| Warfarin | Griseofulvin induces CYP450 enzymes, decreasing warfarin efficacy. Increased risk of clotting. | Major |
| Oral Contraceptives | Reduces contraceptive efficacy, leading to breakthrough bleeding and risk of pregnancy. | Major |
| Cyclosporine | Reduces cyclosporine levels via enzyme induction, risking transplant rejection. | Major |
| Phenobarbital | Decreases griseofulvin levels via enzyme induction, reducing antifungal efficacy. | Moderate |
| Alcohol | May cause disulfiram-like reaction (flushing, tachycardia, nausea). Also increases risk of hepatotoxicity. | Moderate |
Same composition (Griseofulvin (500mg)), different brands: