Overview
Colchicine is an ancient and potent anti-inflammatory medication primarily used for the acute treatment of gout flares and the prophylaxis of gout attacks when initiating urate-lowering therapy. It is also indicated for the management of familial Mediterranean fever.

Mechanism of Action
It binds to tubulin, disrupting the polymerization of microtubules in cells. This action profoundly inhibits the migration and activity of neutrophils (a type of white blood cell) into the inflamed joint space, thereby interrupting the inflammatory response triggered by urate crystals.

Dosage and Administration
For acute gout flares, a common regimen is 1 mg initially, followed by 0.5 mg one hour later. The maximum dose in 24 hours should not exceed 1.5 mg. For prophylaxis during the initiation of allopurinol or febuxostat, the typical dose is 0.5 mg once or twice daily.

Side Effects
Gastrointestinal side effects are exceedingly common and often dose-limiting, including diarrhea, nausea, vomiting, and abdominal pain. At high doses or in susceptible individuals, it can cause severe toxicity, leading to bone marrow suppression, myopathy, and neuropathy.

Contraindications
It is strictly contraindicated in patients with severe renal or hepatic impairment. It should also not be used concurrently with strong CYP3A4 inhibitors (e.g., clarithromycin) or P-glycoprotein inhibitors, as these can dramatically increase colchicine levels and lead to fatal toxicity.

Pregnancy and Lactation
Colchicine crosses the placenta and has been shown to be teratogenic in animal studies. It should be used during pregnancy only if the potential benefit justifies the risk. It is excreted in breast milk, and caution is advised if administered to a nursing woman.