Ultragriseofulvin, a microcrystalline formulation of griseofulvin, is an antifungal agent derived from Penicillium griseofulvum. It works by disrupting fungal microtubule function, inhibiting fungal mitosis. Specifically, it binds to fungal microtubules, preventing spindle formation and arresting cell division. Ultragriseofulvin is fungistatic and effective against dermatophytes, including:

• Trichophyton species.
• Microsporum species.
• Epidermophyton floccosum.

Ultragriseofulvin is primarily used for dermatophyte infections of the skin, hair, and nails. Its clinical applications include:

1. Tinea Infections:
   • Tinea capitis (scalp ringworm): First-line therapy in children.
   • Tinea corporis (body ringworm).
   • Tinea pedis (athlete’s foot).
   • Tinea cruris (jock itch).
2. Onychomycosis (nail infections): Less commonly used due to prolonged treatment duration and newer alternatives.

Adults:

• Microsize Formulation: 500 mg daily in single or divided doses.
• Ultramicrosize Formulation: 250–375 mg daily in single or divided doses.
• Duration:
  • Tinea corporis/cruris: 2–4 weeks.
  • Tinea capitis: 4–6 weeks.
  • Onychomycosis: 6–12 months (or longer).

Children:

• Microsize Formulation: 10 mg/kg/day (max 1 g/day).
• Ultramicrosize Formulation: 5–7.5 mg/kg/day (max 750 mg/day).

Special Populations:

• Hepatic Impairment: Avoid in severe liver disease.
• Renal Impairment: No dose adjustment required.

• Common: Nausea, vomiting, diarrhea, headache, dizziness.
• Serious:
  • Hepatotoxicity: Elevated LFTs (monitor baseline and periodically).
  • Photosensitivity: Severe sunburn with UV exposure.
  • Hypersensitivity Reactions: Rash, urticaria, angioedema.
  • Neurologic Effects: Peripheral neuropathy (rare, with prolonged use).
  • Hematologic Effects: Leukopenia, neutropenia (rare).

1. Hepatic Impairment: Avoid in severe liver disease.
2. Pregnancy: Category C (teratogenic in animal studies; avoid unless benefits outweigh risks).
3. Lactation: Excreted in breast milk; avoid breastfeeding.
4. Photosensitivity: Advise patients to avoid direct sunlight and use sunscreen.
5. Alcohol: Disulfiram-like reaction (flushing, tachycardia).

Ultragriseofulvin interacts with drugs metabolized by CYP450 enzymes:

• Warfarin: Reduced anticoagulant effect (monitor INR).
• Oral Contraceptives: Reduced efficacy (use alternative contraception).
• Cyclosporine: Reduced levels (monitor and adjust dose).
• Barbiturates: Reduced griseofulvin levels (avoid combination).
• Alcohol: Disulfiram-like reaction (avoid during treatment).

• Generic: Griseofulvin (microsize and ultramicrosize).
• Brand Names: Gris-PEG (ultramicrosize), Grifulvin V (microsize).