Colchicine

Anti-inflammatory for hepatic fibrosis and amyloidosis in dogs; microtubule polymerization inhibitor. Anti-inflammatory alkaloid derived from Colchicum autumnale. Mechanism: binds tubulin → inhibits microtubule polymerization → disrupts mitotic spindle formation; also inhibits neutrophil migration, phagocytosis, and lysosomal degranulation. Does not affect uric acid metabolism or excretion. Anti-fibrotic effects via inhibition of collagen secretion. Key information Narrow therapeutic index. GI toxicity is dose-limiting. Drug interaction: cyclosporine, macrolides, and statins increase toxicity. Excreted in milk — avoid in nursing animals. Store at room temperature.

Oral tablets: Administer orally. May be given with food to improve compliance and reduce GI upset. Administer with food to reduce GI adverse effects. to reduce GI upset. Wear gloves when crushing tablets. Administer at consistent times. 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.

GI: severe nausea, vomiting, diarrhea, abdominal cramping (dose-limiting toxicity). Myelosuppression with prolonged use (leukopenia, aplastic anemia). Neuromyopathy. Renal toxicity at high doses. Narrow therapeutic index — toxicity develops quickly.

For animals Reduce dose or extend interval in renal impairment. — dose-reduce in renal impairment (drug accumulates). Use with caution in hepatic impairment. Drug interactions: cyclosporine, azithromycin, diltiazem, fluconazole increase colchicine levels (CYP3A4 inhibitors — toxicity risk). Avoid in pregnant animals. Monitor CBC with prolonged use. For people handling this medication Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Highly toxic plant alkaloid — even small amounts ingested can be fatal. Wear gloves. Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact. Teratogenic. Keep locked away from children. Contact Poison Control immediately if ingested by a human.

Contact your veterinarian immediately. Colchicine overdose is potentially fatal — causes severe GI signs, bone marrow suppression, multiorgan failure. Medical emergency.