Colchiceine

Colchicine tablets are an alkaloid indicated for: Prophylaxis and treatment of gout flares in adults. Familial Mediterranean fever (FMF) in adults and children 4 years or older.

The mechanism by which colchicine exerts its beneficial effect in patients with FMF has not been fully elucidated, however, evidence suggests that colchicine may interfere with the intracellular assembly of the inflammasome complex present in neutrophils and monocytes that mediates activation of interleukin-1β. Additionally, colchicine disrupts cytoskeletal functions through inhibition of β-tubulin polymerization into microtubules and consequently prevents the activation, degranulation and migration of neutrophils thought to mediate some gout symptoms.

The long-term use of colchicine is established for FMF and the prophylaxis of gout flares, but the safety and efficacy of repeat treatment for gout flares has not been evaluated. The dosing regimens for colchicine tablets are different for each indication and must be individualized. The recommended dosage of colchicine tablets depends on the patient's age, renal function, hepatic function and use of coadministered drugs. Colchicine tablets are administered orally without regard to meals. Colchicine tablets are not an analgesic medication and should not be used to treat pain from other causes. Gout Flares: Prophylaxis of Gout Flares: 0.6 mg once or twice daily in adults and adolescents older than 16 years of age. Maximum dose 1.2 mg/day. Treatment of Gout Flares: 1.2 mg (two tablets) at the first sign of a gout flare followed by 0.6 mg (one tablet) one hour later.

Patients with renal or hepatic impairment should not be given colchicine in conjunction with P-gp or strong CYP3A4 inhibitors (this includes all protease inhibitors except fosamprenavir). In these patients, life-threatening and fatal colchicine toxicity has been reported with colchicine taken in therapeutic doses. Patients with renal or hepatic impairment should not be given colchicine in conjunction with P-gp or strong CYP3A4 inhibitors.

Fatal overdoses have been reported with colchicine in adults and children. Keep colchicine out of the reach of children. Blood dyscrasias: myelosuppression, leukopenia, granulocytopenia, thrombocytopenia and aplastic anemia have been reported. Monitor for toxicity and if present consider temporary interruption or discontinuation of colchicine. Drug interaction P-gp and/or CYP3A4 inhibitors: Coadministration of colchicine with P-gp and/or strong CYP3A4 inhibitors has resulted in life-threatening interactions and death. Neuromuscular toxicity: Myotoxicity including rhabdomyolysis may occur, especially in combination with other drugs known to cause this effect. Consider temporary interruption or discontinuation of colchicine.

Prophylaxis of Gout Flares The most commonly reported adverse reaction in clinical trials of colchicine for the prophylaxis of gout was diarrhea. Treatment of Gout Flares The most common adverse reactions reported in the clinical trial with colchicine for treatment of gout flares were diarrhea (23%) and pharyngolaryngeal pain (3%). FMF Gastrointestinal tract adverse effects are the most frequent side effects in patients initiating colchicine, usually presenting within 24 hours, and occurring in up to 20% of patients given therapeutic doses. Typical symptoms include cramping, nausea, diarrhea, abdominal pain and vomiting. These events should be viewed as dose-limiting if severe, as they can herald the onset of more significant toxicity. Prophylaxis of Gout Flares: The most commonly reported adverse reaction in clinical trials for the prophylaxis of gout was diarrhea.

Colchicine is a P-gp and CYP3A4 substrate. Life-threatening and fatal drug interactions have been reported in patients treated with colchicine given with P-gp and strong CYP3A4 inhibitors. If treatment with a P-gp or strong CYP3A4 inhibitor is required in patients with normal renal and hepatic function, the patient's dose of colchicine may need to be reduced or interrupted. Use of colchicine in conjunction with P-gp or strong CYP3A4 inhibitors (this includes all protease inhibitors except fosamprenavir) is contraindicated in patients with renal or hepatic impairment. 7 DRUG INTERACTIONS Colchicine is a substrate of the efflux transporter P-glycoprotein (P-gp). Of the cytochrome P450 enzymes tested, CYP3A4 was mainly involved in the metabolism of colchicine.

Storage Store at 20°C to 25°C (68°F to 77°F). Protect from light. Store container in carton until all contents have been used.