COLCHICINE

Colchicine is an alkaloid obtained from the plant colchicum autumnale . The chemical name for colchicine is ( S)-N- (5,6,7,9- tetrahydro-1,2,3,10-tetramethoxy-9 oxobenzol[a]heptalen­7-yl) acetamide. The structural formula is represented below: Colchicine consists of pale yellow scales or powder; it darkens on exposure to light. Colchicine is soluble in water, freely soluble in alcohol, and slightly soluble in ether. Colchicine Capsules are supplied for oral administration. Each capsule contains 0.6 mg Colchicine and the following inactive ingredients: lactose monohydrate, magnesium stearate, microcrystalline cellulose, pregelatinized starch and sodium starch glycolate. The capsule shell contains gelatin, D&C YELLOW #10, FD&C Blue #1, FDA/E172 BLACK IRON OXIDE, and titanium dioxide. structure

Colchicine Capsules are indicated for prophylaxis of gout flares in adults. Limitations of use: The safety and effectiveness of colchicine for acute treatment of gout flares during prophylaxis has not been studied. Colchicine is not an analgesic medication and should not be used to treat pain from other causes. Colchicine Capsule is an alkaloid indicated for prophylaxis of gout flares in adults (1). Limitations of use: The safety and effectiveness of colchicine for acute treatment of gout flares during prophylaxis has not been studied. Colchicine is not an analgesic medication and should not be used to treat pain from other causes.

The recommended dosage is 0.6 mg (one capsule) once or twice daily (2). Maximum dose 1.2 mg/day. Colchicine Capsule is administered orally, without regard to meals (2). 2.1 Recommended Dosage for Gout Prophylaxis For prophylaxis of gout flares, the recommended dosage of colchicine is 0.6 mg once or twice daily. The maximum dose is 1.2 mg per day. Colchicine is administered orally, without regard to meals.

Patients with renal or hepatic impairment should not be given colchicine with drugs that inhibit both P- glycoprotein and CYP3A4 inhibitors [See Drug Interactions (7)]. Combining these dual inhibitors with colchicine in patients with renal or hepatic impairment has resulted in life-threatening or fatal colchicine toxicity. Patients with both renal and hepatic impairment should not be given colchicine. • Patients with renal or hepatic impairment should not be given colchicine in conjunction with drugs that inhibit both P-gp and CYP3A4 (4). • Patients with both renal and hepatic impairment should not be given colchicine (4).

Gastrointestinal disorders are the most common adverse reactions with colchicine. They are often the first signs of toxicity and may indicate that the colchicine dose needs to be reduced or therapy stopped. These include diarrhea, nausea, vomiting, and abdominal pain. Colchicine has been reported to cause neuromuscular toxicity, which may present as muscle pain or weakness [ see Warnings and Precautions (5.4)]. Toxic manifestations associated with colchicine include myelosuppression, disseminated intravascular coagulation, and injury to cells in the renal, hepatic, circulatory, and central nervous system. These most often occur with excessive accumulation or overdosage [see Overdosage (10)]. The following reactions have been reported with colchicine. These have been generally reversible by interrupting treatment or lowering the dose of colchicine: D i gestive : abdominal cramping, abdominal pain, diarrhea, lactose intolerance, nausea, vomiting N eurological : sensory motor neuropathy D ermatological : alopecia, maculopapular rash, purpura, rash H e m atological : leukopenia, granulocytopenia, thrombocytopenia, pancytopenia, aplastic anemia H epatobiliary : elevated AST, elevated ALT Musculoskeletal : myopathy, elevated CPK, myotonia, muscle weakness, muscle pain, rhabdomyolysis R eproductive : azoospermia, oligospermia The most commonly reported adverse reactions with colchicine are gastrointestinal symptoms, including diarrhea, nausea, vomiting, and abdominal pain ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Endo at 1-800-828-9393 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Colchicine is a substrate of the efflux transporter P-glycoprotein (P-gp), and the CYP3A4 metabolizing enzyme. Fatal drug interactions have been reported when colchicine is administered with clarithromycin, a dual inhibitor of CYP3A4 and P-glycoprotein. Toxicities have also been reported when colchicine is administered with inhibitors of CYP3A4 that may not be potent inhibitors of P-gp (e.g., grapefruit juice, erythromycin, verapamil), or inhibitors of P-gp that may not be potent inhibitors of CYP3A4 (e.g., cyclosporine). Patients with renal or hepatic impairment should not be given colchicine with drugs that inhibit both P-­ glycoprotein and CYP3A4 [See Contraindications (4)]. Combining these dual inhibitors with colchicine in patients with renal and hepatic impairment has resulted in life-threatening or fatal colchicine toxicity. Physicians should ensure that patients are suitable candidates for treatment with colchicine and remain alert for signs and symptoms of toxic reactions associated with increased colchicine exposure due to drug interactions. Signs and symptoms of colchicine toxicity should be evaluated promptly and, if toxicity is suspected, colchicine should be discontinued immediately. • Coadministration of P-gp or CYP3A4 inhibitors or inhibitors of both P-gp and CYP3A4 (e.g., clarithromycin or cyclosporine) have been reported to lead to colchicine toxicity. The potential for drug-drug interactions must be considered prior to and during therapy. • Concomitant use of colchicine and inhibitors of CYP3A4 or P-gp should be avoided if possible. If coadministration of colchicine and an inhibitor of CYP3A4 or P-gp is necessary, the dose of colchicine should be reduced and the patient should be monitored carefully for colchicine toxicity ( 7 , 12.3 ). 7.1 CYP3A4 The concomitant use of colchicine and CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole, grapefruit juice, erythromycin, verapamil, etc.) should be avoided due to the potential for serious and life-threatening toxicity [See Warnings and Precautions (5.3) and Clinical Pharmacology (12)]. If coadministration of colchicine and a CYP3A4 inhibitor is necessary, the dose of colchicine should be adjusted by either reducing the daily dose or reducing the dose frequency, and the patient should be monitored carefully for colchicine toxicity [See Clinical Pharmacology ( 12 )]. 7.2 P-glycoprotein The concomitant use of colchicine and inhibitors of P-glycoprotein (e.g. clarithromycin, ketoconazole, cyclosporine, etc.) should be avoided due to the potential for serious and life-threatening toxicity [See Warnings and Precautions (5.3) and Clinical Pharmacology (12)]. If coadministration of colchicine and a P-gp inhibitor is necessary, the dose of colchicine should be adjusted by either reducing the daily dose or reducing the dose frequency, and the patient should be monitored carefully for colchicine toxicity [See C linical Pharmacology ( 12 )]. 7.3 HMG-CoA Reductase Inhibitors and Fibrates Some drugs such as HMG-CoA reductase inhibitors and fibrates may increase the risk of myopathy when combined with colchicine. Complaints of muscle pain or weakness could be an indication to check serum creatinine kinase levels for signs of myopathy. 7.4 Drug-Drug Interaction Studies Four pharmacokinetic studies evaluated the effects of coadministration of voriconazole (200 mg BID), fluconazole (200 mg QD), cimetidine (800 mg BID), and propafenone (225 mg BID) on systemic levels of colchicine. Colchicine can be administered with these drugs at the tested doses without a need for dose adjustment. However, these results should not be extrapolated to other coadministered drugs [See Drug-Drug Interactions ( 7.1 , 7.2 ) and Pharmacokinetics ( 12.3 )].