Colchicine Drug Information

• Colchicine tablets are an alkaloid indicated for:
• Prophylaxis and treatment of gout flares in adults ( 1.1 ).
• Familial Mediterranean fever (FMF) in adults and children 4 years or older ( Error! Hyperlink reference not valid. ). 1.1 Gout Flares Colchicine tablets are indicated for prophylaxis and the treatment of acute gout flares.
• Prophylaxis of Gout Flares: Colchicine tablets are indicated for prophylaxis of gout flares.
• Treatment of Gout Flares: Colchicine tablets are indicated for treatment of acute gout flares when taken at the first sign of a flare. 1.2 Familial Mediterranean Fever (FMF) Colchicine tablets are indicated in adults and children four years or older for treatment of familial Mediterranean fever (FMF).

• 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

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. ).

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.

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.

Patients with renal or hepatic impairment should not be given colchicine tablets 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 tablets in conjunction with P-gp or strong CYP3A4 inhibitors ( Error! Hyperlink reference not valid. ). In these patients, life-threatening and fatal colchicine toxicity has been reported with colchicine taken in therapeutic doses ( Error! Hyperlink reference not valid. ).

The exact dose of colchicine that produces significant toxicity is unknown. Fatalities have occurred after ingestion of a dose as low as 7 mg over a four day period, while other patients have survived after ingesting more than 60 mg. A review of 150 patients who overdosed on colchicine found that those who ingested less than 0.5 mg/kg survived and tended to have milder toxicities such as gastrointestinal symptoms, whereas those who took 0.5 to 0.8 mg/kg had more severe reactions such as myelosuppression.

There was 100% mortality in those who ingested more than 0.8 mg/kg. The first stage of acute colchicine toxicity typically begins within 24 hours of ingestion and includes gastrointestinal symptoms such as abdominal pain, nausea, vomiting, diarrhea and significant fluid loss, leading to volume depletion. Peripheral leukocytosis may also be seen.

Life-threatening complications occur during the second stage, which occurs 24 to 72 hours after drug administration, attributed to multiorgan failure and its consequences. Death is usually a result of respiratory depression and cardiovascular collapse. If the patient survives, recovery of multiorgan injury may be accompanied by rebound leukocytosis and alopecia starting about one week after the initial ingestion.

Treatment of colchicine poisoning should begin with gastric lavage and measures to prevent shock. Otherwise, treatment is symptomatic and supportive. No specific antidote is known.

Colchicine is not effectively removed by dialysis .