colchicine: clinical use

Prescribing considerations

• Confirm the indication and review prescription, non-prescription and herbal products because colchicine has a narrow therapeutic window.
• Assess renal and hepatic function, age, frailty, gastrointestinal or cardiovascular disease, blood abnormalities and interacting medicines.
• Counsel patients about gastrointestinal toxicity, blood-disorder symptoms and muscle symptoms.

Contraindications and cautions

• Hypersensitivity to colchicine or an excipient.
• Severe blood dyscrasia.
• Severe renal or hepatic impairment and haemodialysis.
• Renal or hepatic impairment with a P-glycoprotein inhibitor or strong CYP3A4 inhibitor.
• Pregnancy, breastfeeding, or childbearing potential without effective contraception, according to the selected product's SmPC.

Monitoring

• Periodic full blood counts because severe marrow suppression may develop gradually or suddenly.
• Monitor renal and hepatic function where impairment or relevant interacting treatment is present.
• Arrange urgent haematological investigation for fever, stomatitis, sore throat, bruising or prolonged bleeding.
• Investigate new muscle pain or weakness and review concomitant medicines.

Clinical pharmacology

Colchicine modifies microtubule function and inflammatory-cell activity. It accumulates in leucocytes, undergoes partial hepatic metabolism and biliary handling, and is eliminated through faecal and renal routes. It is a CYP3A4 and P-glycoprotein substrate.

Formulation and product differences

• The selected product is an oral, uncoated tablet containing lactose.
• Store it in its original packaging to protect it from light.
• Appearance, excipients and packaging can differ between products; check the product-specific SmPC or leaflet.

Tablet

Route: Oral

Strengths: 500 micrograms