In renal impairment, colchicine can cause which toxicities?

• A. Cardiac arrhythmias
• B. GI, neuromuscular, and bone marrow toxicity
• C. Hepatic failure
• D. Renal failure

Answer: (B)

Colchicine toxicities in someone with renal impairment mainly come from the drug building up in the body due to reduced clearance. The most clinically important effects are gastrointestinal symptoms (nausea, vomiting, diarrhea) from damage to rapidly dividing cells of the GI mucosa, neuromuscular toxicity (muscle weakness and possible myopathy), and bone marrow suppression (neutropenia, anemia, thrombocytopenia) from impaired cell division in the marrow. These three symptoms together reflect colchicine’s mechanism of inhibiting microtubule formation, which disrupts the function of rapidly dividing tissues and muscle. Hepatic failure or renal failure themselves are not typical direct toxicities of colchicine, and cardiac arrhythmias are possible only rarely, not the characteristic pattern seen with accumulation in renal impairment.