Griseofulvin

Antifungal for dermatophytosis (ringworm) in horses, cats, and dogs; oral administration; inhibits fungal cell division. Fungistatic antifungal antibiotic (griseofulvin). Mechanism: binds to tubulin → disrupts microtubule assembly and mitotic spindle formation → inhibits fungal cell division. Deposits in newly synthesized keratin → fungistatic activity in growing hair and nail. Oral administration; absorbed with fatty meals. Active only against dermatophytes (Trichophyton, Microsporum, Epidermophyton). Key information Teratogenic — do not use in pregnant animals. Administer with fatty meal to improve absorption. Prolonged treatment course (4–12 weeks). Monitor CBC. Not effective against Microsporum gypseum. Drug interactions: phenobarbital reduces efficacy.

Oral tablets: Administer orally. May be given with food to improve compliance and reduce GI upset. Administer with food to reduce GI adverse effects. (particularly fatty food to enhance absorption — high-fat meal increases bioavailability). Tablets may be crushed and mixed with food. Wear gloves when handling. Long treatment course required (4–8 weeks minimum). Store at room temperature; protect from light. If a dose is missed Administer as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and resume the normal schedule. Never double up doses to make up for a missed one. Administer with a fatty meal. Complete the full course.

GI: vomiting, diarrhea, anorexia (most common). Hepatotoxicity: elevated liver enzymes (monitor with prolonged use). Hematologic: leukopenia, anemia (rare). Teratogenic (do not use in pregnant animals). Photosensitivity. Cats: severe GI side effects and idiosyncratic bone marrow suppression — use with caution. Ataxia (rare CNS effect).

For animals Avoid in pregnant animals. — teratogenic; do not use in pregnant animals or animals intended for breeding. Monitor liver enzymes with prolonged use. Cats: idiosyncratic bone marrow suppression — Monitor CBC periodically with prolonged use. Use with caution in cats. Drug interaction: barbiturates reduce griseofulvin absorption. For people handling this medication Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Antifungal — Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact. Teratogenic — do NOT handle if pregnant. Wear gloves. Carcinogenic potential with prolonged exposure. Keep out of reach of children.

Contact your veterinarian. Overdose causes GI signs and blood abnormalities. Teratogenic — do not use in pregnant animals.