Colchicine

5 WARNINGS AND PRECAUTIONS • Fatal overdoses have been reported with colchicine in adults and children. Keep colchicine tablets out of the reach of children ( Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ). • Blood dyscrasias: myelosuppression, leukopenia, granulocytopenia, thrombocytopenia and aplastic anemia have been reported ( Error! Hyperlink reference not valid. ). • Monitor for toxicity and if present consider temporary interruption or discontinuation of colchicine ( Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ). • 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 ( Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ). • 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 tablets ( Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ). 5.1 Fatal Overdose Fatal overdoses, both accidental and intentional, have been reported in adults and children who have ingested colchicine [see Error! Hyperlink reference not valid. ] . Colchicine tablets should be kept out of the reach of children. 5.2 Blood Dyscrasias Myelosuppression, leukopenia, granulocytopenia, thrombocytopenia, pancytopenia and aplastic anemia have been reported with colchicine used in therapeutic doses. 5.3 Drug Interactions 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 [see Error! Hyperlink reference not valid. ] . Use of colchicine tablets 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 [see Error! Hyperlink reference not valid. ]. 5.4 Neuromuscular Toxicity Colchicine-induced neuromuscular toxicity and rhabdomyolysis have been reported with chronic treatment in therapeutic doses. Patients with renal dysfunction and elderly patients, even those with normal renal and hepatic function, are at increased risk. Concomitant use of atorvastatin, simvastatin, pravastatin, fluvastatin, lovastatin, gemfibrozil, fenofibrate, fenofibric acid or benzafibrate (themselves associated with myotoxicity) or cyclosporine with colchicine tablets may potentiate the development of myopathy [see Error! Hyperlink reference not valid. ] . Once colchicine is stopped, the symptoms generally resolve within one week to several months.

6 ADVERSE REACTIONS 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 tablets 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 tablets, 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. • Treatment of Gout Flares: The most common adverse reactions reported in the clinical trial for gout were diarrhea (23%) and pharyngolaryngeal pain (3%). • FMF: Most common adverse reactions (up to 20%) are abdominal pain, diarrhea, nausea and vomiting. These effects are usually mild, transient and reversible upon lowering the dose ( Error! Hyperlink reference not valid. ). To report SUSPECTED ADVERSE REACTIONS, contact Dr. Reddy’s Laboratories Inc., at 1-888- 375-3784 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience in Gout Because clinical studies are conducted under widely varying and controlled conditions, adverse reaction rates observed in clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not predict the rates observed in a broader patient population in clinical practice. In a randomized, double-blind, placebo-controlled trial in patients with a gout flare, gastrointestinal adverse reactions occurred in 26% of patients using the recommended dose (1.8 mg over one hour) of colchicine tablets compared to 77% of patients taking a nonrecommended high dose (4.8 mg over six hours) of colchicine and 20% of patients taking placebo. Diarrhea was the most commonly reported drug-related gastrointestinal adverse event. As shown in Table 3, diarrhea is associated with colchicine tablets treatment. Diarrhea was more likely to occur in patients taking the high-dose regimen than the low-dose regimen. Severe diarrhea occurred in 19% and vomiting occurred in 17% of patients taking the nonrecommended high-dose colchicine regimen but did not occur in the recommended low-dose colchicine tablets regimen. Table 3. Number (%) of Patients with at Least One Drug-Related Treatment-Emergent Adverse Event with an Incidence of ≥ 2% of Patients in Any Treatment Group MedDRA System Organ Class MedDRA Preferred Term Colchicine Tablets Dose Placebo (N = 59) n (%) High (N= 52) n (%) Low (N = 74) n (%) Number of Patients with at Least One Drug-Related TEAE 40 (77) 27 (37) 16 (27) Gastrointestinal Disorders 40 (77) 19 (26) 12 (20) Diarrhea 40 (77) 17 (23) 8 (14) Nausea 9 (17) 3 (4) 3 (5) Vomiting 9 (17) 0 0 Abdominal Discomfort 0 0 2 (3) General Disorders and Administration Site Conditions 4 (8) 1 (1) 1 (2) Fatigue 2 (4) 1 (1) 1 (2) Metabolic and Nutrition Disorders 0 3 (4) 2 (3) Gout 0 3 (4) 1 (2) Nervous System Disorders 1 (2) 1 (1.4) 2 (3) Headache 1 (2) 1 (1) 2 (3) Respiratory Thoracic Mediastinal Disorders 1 (2) 2 (3) 0 Pharyngolaryngeal Pain 1 (2) 2 (3) 0 6.2 Postmarketing Experience Serious toxic manifestations associated with colchicine include myelosuppression, disseminated intravascular coagulation and injury to cells in the renal, hepatic, circulatory and central nervous systems. These most often occur with excessive accumulation or overdosage [see Error! Hyperlink reference not valid. ] . The following adverse reactions have been identified with colchicine. These have been generally reversible upon temporarily interrupting treatment or lowering the dose of colchicine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Neurological: sensory motor neuropathy Dermatological: alopecia, maculopapular rash, purpura, rash Digestive: abdominal cramping, abdominal pain, diarrhea, lactose intolerance, nausea, vomiting Hematological: leukopenia, granulocytopenia, thrombocytopenia, pancytopenia, aplastic anemia Hepatobiliary: elevated AST, elevated ALT Musculoskeletal: myopathy, elevated CPK, myotonia, muscle weakness, muscle pain, rhabdomyolysis Reproductive: azoospermia, oligospermia

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. If colchicine tablets are administered with drugs that inhibit P-gp, most of which also inhibit CYP3A4, increased concentrations of colchicine are likely. Fatal drug interactions have been reported. Physicians should ensure that patients are suitable candidates for treatment with colchicine tablets and remain alert for signs and symptoms of toxicities related to increased colchicine exposure as a result of a drug interaction. Signs and symptoms of colchicine tablets toxicity should be evaluated promptly and, if toxicity is suspected, colchicine tablets should be discontinued immediately. Table 4 provides recommendations as a result of other potentially significant drug interactions. Table 1 provides recommendations for strong and moderate CYP3A4 inhibitors and P-gp inhibitors. Table 4. Other Potentially Significant Drug Interactions Concomitant Drug Class or Food Noted or Anticipated Outcome Clinical Comment HMG-CoA Reductase Inhibitors: atorvastatin, fluvastatin, lovastatin, pravastatin, simvastatin Pharmacokinetic and/or pharmacodynamic interaction: the addition of one drug to a stable long-term regimen of the other has resulted in myopathy and rhabdomyolysis (including a fatality) Weigh the potential benefits and risks and carefully monitor patients for any signs or symptoms of muscle pain, tenderness, or weakness, particularly during initial therapy; monitoring CPK (creatine phosphokinase) will not necessarily prevent the occurrence of severe myopathy. Other Lipid-Lowering Drugs: fibrates, gemfibrozil Digitalis Glycosides: digoxin P-gp substrate; rhabdomyolysis has been reported Coadministration of P-gp and/or CYP3A4 inhibitors (e.g., clarithromycin or cyclosporine) have been demonstrated to alter the concentration of colchicine. The potential for drug-drug interactions must be considered prior to and during therapy. See FPI for a complete list of reported and potential interactions ( Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ).

Drug Interactions In Vitro Drug Interactions In vitro studies in human liver microsomes have shown that colchicine is not an inhibitor or inducer of CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 or CYP3A4 activity. In Vivo Drug Interactions The effects of coadministration of other drugs with colchicine tablets on C max , AUC and C min are summarized in Table 6 (effect of other drugs on colchicine) and Table 7 (effect of colchicine on other drugs). For information regarding clinical recommendations, see Table 1 in Dose Modification for Coadministration of Interacting Drugs [see Error! Hyperlink reference not valid. ] . Table 6. Drug Interactions: Pharmacokinetic Parameters for Colchicine Tablets in the Presence of the Coadministered Drug Coadministered Drug Dose of Coadministered Drug (mg) Dose of Colchicine Tablets (mg) N % Change in Colchicine Concentrations from Baseline (Range: Min – Max) C max AUC 0-t Cyclosporine 100 mg single dose 0.6 mg single dose 23 270.0 (62.0 to 606.9) 259.0 (75.8 to 511.9) Clarithromycin 250 mg twice daily, 7 days 0.6 mg single dose 23 227.2 (65.7 to 591.1) 281.5 (88.7 to 851.6) Ketoconazole 200 mg twice daily, 5 days 0.6 mg single dose 24 101.7 (19.6 to 219.0) 212.2 (76.7 to 419.6) Ritonavir 100 mg twice daily, 5 days 0.6 mg single dose 18 184.4 (79.2 to 447.4) 296.0 (53.8 to 924.4) Verapamil 240 mg daily, 5 days 0.6 mg single dose 24 40.1 (-47.1 to 149.5) 103.3 (-9.8 to 217.2) Diltiazem 240 mg daily, 7 days 0.6 mg single dose 20 44.2 (-46.0 to 318.3) 93.4 (-30.2 to 338.6) Azithromycin 500 mg x 1 day, then 250 mg x 4 days 0.6 mg single dose 21 21.6 (-41.7 to 222.0) 57.1 (-24.3 to 241.1) Grapefruit juice 240 mL twice daily, 4 days 0.6 mg single dose 21 -2.55 (-53.4 to 55.0) -2.36 (-46.4 to 62.2) Estrogen-containing oral contraceptives: In healthy female volunteers given ethinyl estradiol and norethindrone (Ortho-Novum ® 1/35) coadministered with colchicine tablets (0.6 mg twice daily × 14 days), hormone concentrations are not affected. In healthy volunteers given theophylline coadministered with colchicine tablets (0.6 mg twice daily × 14 days), theophylline concentrations were not affected. Table 7. Drug Interactions: Pharmacokinetic Parameters for Coadministration of Drug in the Presence of Colchicine Tablets Coadministered Drug Dose of Coadministered Drug (mg) Dose of Colchicine Tablets (mg) N % Change in Coadministered Drug Concentrations from Baseline (Range: Min – Max) C max AUC 0-t Theophylline 300 mg (elixir) single dose 0.6 mg twice daily x 14 days 27 1.6 (-30.4 to 23.1) 1.6 (-28.5 to 27.1) Ethinyl Estradiol (Ortho-Novum ® 1/35) 21-day cycle (active treatment) + 7-day placebo 0.6 mg twice daily x 14 days 27 Conducted in healthy adult females -6.7 (-40.3 to 44.7) -3.0 AUC Ʈ (-25.3 to 24.9) Norethindrone (Ortho-Novum ® 1/35) 0.94 (-37.3 to 59.4) -1.6 (-32.0 to 33.7)

8 USE IN SPECIFIC POPULATIONS • In the presence of mild to moderate renal or hepatic impairment, adjustment of dosing is not required for treatment of gout flare, prophylaxis of gout flare and FMF, but patients should be monitored closely ( Error! Hyperlink reference not valid. ). • In patients with severe renal impairment for prophylaxis of gout flares, the starting dose should be 0.3 mg/day for gout flares, no dose adjustment is required, but a treatment course should be repeated no more than once every two weeks. In FMF patients, start with 0.3 mg/day, and any increase in dose should be done with close monitoring ( Error! Hyperlink reference not valid. ). • In patients with severe hepatic impairment, a dose reduction may be needed in prophylaxis of gout flares and FMF patients; while a dose reduction may not be needed in gout flares, a treatment course should be repeated no more than once every two weeks ( Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ). • For patients undergoing dialysis, the total recommended dose for prophylaxis of gout flares should be 0.3 mg given twice a week with close monitoring. For treatment of gout flares, the total recommended dose should be reduced to 0.6 mg (one tablet) x 1 dose and the treatment course should not be repeated more than once every two weeks. For FMF patients, the starting dose should be 0.3 mg/day and dosing can be increased with close monitoring ( Error! Hyperlink reference not valid. ). • Females and Males of Reproductive Potential: Advise males that colchicine tablets may transiently impair fertility ( Error! Hyperlink reference not valid. ). • Geriatric Use: The recommended dose of colchicine should be based on renal function ( Error! Hyperlink reference not valid. ). 8.1 Pregnancy Risk Summary Available data from published literature on colchicine use in pregnancy over several decades have not identified any drug associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Error! Hyperlink reference not valid. ). Colchicine crosses the human placenta. Although animal reproductive and developmental studies were not conducted with colchicine tablets, published animal reproduction and development studies indicate that colchicine causes embryofetal toxicity, teratogenicity and altered postnatal development at exposures within or above the clinical therapeutic range. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Human Data Available data from published observational studies, case series, and case reports over several decades do not suggest an increased risk for major birth defects or miscarriage in pregnant women with rheumatic diseases (such as rheumatoid arthritis, Behcet’s disease, or familial Mediterranean fever (FMF) treated with colchicine at therapeutic doses during pregnancy. Limitations of these data include the lack of randomization and inability to control for confounders such as underlying maternal disease and maternal use of concomitant medications. 8.2 Lactation Risk Summary Colchicine is present in human milk (see Error! Hyperlink reference not valid. ) . Adverse events in breastfed infants have not been reported in the published literature after administration of colchicine to lactating women. There are no data on the effects of colchicine on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for colchicine tablets and any potential adverse effects on the breastfed child from colchicine tablets or from the underlying maternal condition. Data Limited published data from case reports and a small lactation study demonstrate that colchicine is present in breastmilk. A systematic review of literature reported no adverse effects in 149 breastfed children. In a prospective observational cohort study, no gastrointestinal or other symptoms were reported in 38 colchicine-exposed breastfed infants. 8.3 Females and Males of Reproductive Potential Infertility Case reports and epidemiology studies in human male subjects on colchicine therapy indicated that infertility from colchicine is rare and may be reversible. A case report indicated that azoospermia was reversed when therapy was stopped. Case reports and epidemiology studies in female subjects on colchicine therapy have not established a clear relationship between colchicine use and female infertility. However, since the progression of FMF without treatment may result in infertility, the use of colchicine needs to be weighed against the potential risks [see Error! Hyperlink reference not valid. ] . 8.4 Pediatric Use The safety and efficacy of colchicine in children of all ages with FMF has been evaluated in uncontrolled studies. There does not appear to be an adverse effect on growth in children with FMF treated long-term with colchicine. Safety and effectiveness of colchicine in pediatric patients with gout has not been established. 8.5 Geriatric Use Clinical studies with colchicine for prophylaxis and treatment of gout flares and for treatment of FMF did not include sufficient numbers of patients aged 65 years and older to determine whether they respond differently from younger patients. In general, dose selection for an elderly patient with gout should be cautious, reflecting the greater frequency of decreased renal function, concomitant disease or other drug therapy [see Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ] . 8.6 Renal Impairment Colchicine is significantly excreted in urine in healthy subjects. Clearance of colchicine is decreased in patients with impaired renal function. Total body clearance of colchicine was reduced by 75% in patients with end-stage renal disease undergoing dialysis. Prophylaxis of Gout Flares For prophylaxis of gout flares in patients with mild (estimated creatinine clearance Cl cr 50 to 80 mL/min) to moderate (Cl cr 30 to 50 mL/min) renal function impairment, adjustment of the recommended dose is not required, but patients should be monitored closely for adverse effects of colchicine. However, in patients with severe impairment, the starting dose should be 0.3 mg per day and any increase in dose should be done with close monitoring. For the prophylaxis of gout flares in patients undergoing dialysis, the starting doses should be 0.3 mg given twice a week with close monitoring [see Error! Hyperlink reference not valid. ] . Treatment of Gout Flares For treatment of gout flares in patients with mild (Cl cr 50 to 80 mL/min) to moderate (Cl cr 30 to 50 mL/min) renal function impairment, adjustment of the recommended dose is not required, but patients should be monitored closely for adverse effects of colchicine tablets. However, in patients with severe impairment, while the dose does not need to be adjusted for the treatment of gout flares, a treatment course should be repeated no more than once every two weeks. For patients with gout flares requiring repeated courses, consideration should be given to alternate therapy. For patients undergoing dialysis, the total recommended dose for the treatment of gout flares should be reduced to a single dose of 0.6 mg (one tablet). For these patients, the treatment course should not be repeated more than once every two weeks [see Error! Hyperlink reference not valid. ] . FMF Although pharmacokinetics of colchicine in patients with mild (Cl cr 50 to 80 mL/min) and moderate (Cl cr 30 to 50 mL/min) renal impairment is not known, these patients should be monitored closely for adverse effects of colchicine. Dose reduction may be necessary. In patients with severe renal failure (Cl cr less than 30 mL/min) and end-stage renal disease requiring dialysis, colchicine tablets may be started at the dose of 0.3 mg/day. Any increase in dose should be done with adequate monitoring of the patient for adverse effects of colchicine tablets [see Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ] . 8.7 Hepatic Impairment The clearance of colchicine may be significantly reduced and plasma half-life prolonged in patients with chronic hepatic impairment compared to healthy subjects [see Error! Hyperlink reference not valid. ] . Prophylaxis of Gout Flares For prophylaxis of gout flares in patients with mild to moderate hepatic function impairment, adjustment of the recommended dose is not required, but patients should be monitored closely for adverse effects of colchicine. Dose reduction should be considered for the prophylaxis of gout flares in patients with severe hepatic impairment [see Error! Hyperlink reference not valid. ] . Treatment of Gout Flares For treatment of gout flares in patients with mild to moderate hepatic function impairment, adjustment of the recommended colchicine tablets dose is not required, but patients should be monitored closely for adverse effects of colchicine tablets. However, for the treatment of gout flares in patients with severe impairment, while the dose does not need to be adjusted, the treatment course should be repeated no more than once every two weeks. For these patients, requiring repeated courses for the treatment of gout flares, consideration should be given to alternate therapy [see Error! Hyperlink reference not valid. ] . FMF In patients with severe hepatic disease, dose reduction should be considered with careful monitoring [see Error! Hyperlink reference not valid. , Error! Hyperlink reference not valid. ] .