Pharmacology · Other antigout agents
Colchicine !
An old plant-derived tablet that calms gout flares and familial Mediterranean fever. Small margin: diarrhoea warns of toxicity; overdose can kill.
Updated 2026-11-01
The figure shows cow tubulin with colchicine in its binding site on β-tubulin; the human protein is almost identical.
Mechanism of action
Colchicine binds β-tubulin and stops it from polymerising into microtubules. Neutrophils then cannot activate, degranulate or migrate into the joint where urate crystals sit, and assembly of the NLRP3 inflammasome, which activates interleukin-1β, is disrupted. It has no effect on uric acid levels.
- Binds β-tubulin
- Microtubules cannot form
- Neutrophils stop migrating; less IL-1β
- Crystal inflammation settles
Pharmacokinetics
- Absorption
- Oral
- Metabolism
- Substrate of CYP3A4 and of P-glycoprotein, the basis of its dangerous interactions
- Elimination
- Not removed effectively by dialysis; kidney and liver impairment raise toxicity
Indications
- Prevention and treatment of gout flares Gout →
- Familial Mediterranean fever Familial Mediterranean fever and other hereditary autoinflammatory syndromes →
Adverse effects
Common
- Diarrhoea
- Nausea and vomiting
- Abdominal pain
Contraindications
- Kidney or liver impairment together with a P-glycoprotein or strong CYP3A4 inhibitor
Key interactions
- Clarithromycin, HIV protease inhibitors, ketoconazole-type azoles, verapamil, grapefruit juice
- Block CYP3A4 or P-glycoprotein; colchicine levels rise and fatal toxicity has occurred.
- Ciclosporin
- Raises colchicine levels and adds myopathy risk.
- Statins and fibrates
- Higher risk of myopathy and rhabdomyolysis.
What is monitored
- Diarrhoea, vomiting or abdominal pain as early toxicity
- Blood count during long-term use
- Muscle weakness or pain; kidney and liver function
- Every new medicine checked for CYP3A4 or P-glycoprotein inhibition
Administration and safety
- Oral tablet or capsule only.
- Kept out of the reach of children: small amounts can be fatal.
- Grapefruit juice is avoided.
Nursing care
- Review every other medicine for interactions before giving it, especially macrolides, azoles, protease inhibitors, verapamil and ciclosporin.
- Report diarrhoea, vomiting or abdominal pain: they are the first signs of toxicity.
- Teach to report muscle pain or weakness, numbness, unusual bleeding or bruising, or fever.
- Teach that it is stored away from children.
Pregnancy and breastfeeding
Human data are limited; the treating team weighs benefits and risks.
Test yourself
Think of the answer, then tap the question to see it.
What is the earliest sign of colchicine toxicity?
Gastrointestinal symptoms: diarrhoea, nausea, vomiting and abdominal pain.
A patient on colchicine is prescribed clarithromycin. Why is this dangerous?
Clarithromycin strongly inhibits CYP3A4 and P-glycoprotein; colchicine levels rise and fatal toxicity has been reported.
Does colchicine lower uric acid?
No. It calms crystal-induced inflammation by acting on neutrophil microtubules; urate levels are unchanged.
Which genetic autoinflammatory disease is treated with colchicine?
Familial Mediterranean fever.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Colchicine: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); DailyMed - COLCHICINE tablet (DailyMed (U.S. National Library of Medicine), 2024); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 42 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.