Colchicine
0.6mg Tablets

What is the most important information I should know about Colchicine?

Colchicine can cause serious side effects or death if levels of Colchicine are too high in your body.

• Taking certain medicines with Colchicine can cause your level of Colchicine to be too high, especially if you have kidney or liver problems.
• Tell your healthcare provider about all your medical conditions, including if you have kidney or liver problems. Your dose of Colchicine may need to be changed.
• Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements.
• Even medicines that you take for a short period of time, such as antibiotics, can interact with Colchicine and cause serious side effects or death.
• Talk to your healthcare provider or pharmacist before taking any new medicine.
• Especially tell your healthcare provider if you take:

Ask your healthcare provider or pharmacist if you are not sure if you take any of the medicines listed above. This is not a complete list of all the medicines that can interact with Colchicine.

• Know the medicines you take. Keep a list of them and show it to your healthcare provider and pharmacist when you get a new medicine.
• Keep Colchicine out of the reach of children.

What is Colchicine?

Colchicine is a prescription medicine used to:

• prevent and treat gout flares in adults
• treat familial Mediterranean fever (FMF) in adults and children age four or older

Colchicine is not a pain medicine and it should not be taken to treat pain related to other conditions unless specifically prescribed for those conditions.

Who should not take Colchicine?

Do not take Colchicine if you have liver or kidney problems and you take certain other medicines. Serious side effects, including death, have been reported in these patients even when taken as directed. See "What is the most important information I should know about Colchicine?"

What should I tell my healthcare provider before starting Colchicine?

See "What is the most important information I should know about Colchicine?"
Before you take Colchicine tell your healthcare provider about all your medical conditions including if you:

• have liver or kidney problems
• are pregnant or plan to become pregnant. It is not known if Colchicine will harm your unborn baby. Talk to your healthcare provider if you are pregnant or plan to become pregnant.
• are breast-feeding or plan to breast-feed. Colchicine passes into your breast milk. You and your healthcare provider should decide if you will take Colchicine or breast-feed. If you take Colchicine and breast-feed, you should talk to your child's healthcare provider about how to watch for side effects in your child.

Tell your healthcare provider about all the medicines you take, including ones that you may only be taking for a short time, such as antibiotics. See "What is the most important information I should know about Colchicine?" Do not start a new medicine without talking to your healthcare provider.

Using Colchicine with certain other medicines, such as cholesterol-lowering medications and digoxin, can affect each other causing serious side effects. Your healthcare provider may need to change your dose of Colchicine. Talk to your healthcare provider about whether the medications you are taking might interact with Colchicine, and what side effects to look for.

How should I take Colchicine?

• Take Colchicine exactly as your healthcare provider tells you to take it. If you are not sure about your dosing, call your healthcare provider.
• Colchicine can be taken with or without food.
• If you take too much Colchicine go to the nearest hospital emergency room right away.
• Do not stop taking Colchicine even if you start to feel better, unless your healthcare provider tells you.
• Your healthcare provider may do blood tests while you take Colchicine.
• If you take Colchicine daily and you miss a dose, then take it as soon as you remember. If it is almost time for your next dose, just skip the missed dose. Take the next dose at your regular time. Do not take 2 doses at the same time.
• If you have a gout flare while taking Colchicine daily, report this to your healthcare provider.

What should I avoid while taking Colchicine?

• Avoid eating grapefruit or drinking grapefruit juice while taking Colchicine. It can increase your chances of getting serious side effects.

What are the possible side effects of Colchicine?

Colchicine can cause serious side effects or even cause death. See "What is the most important information I should know about Colchicine?"

Get medical help right away, if you have:

• Muscle weakness or pain
• Numbness or tingling in your fingers or toes
• Unusual bleeding or bruising
• Increased infections
• Feel weak or tired
• Pale or gray color to your lips, tongue, or palms of your hands
• Severe diarrhea or vomiting

Gout Flares: The most common side effect of Colchicine in people who have gout flares is diarrhea.
FMF: The most common side effects of Colchicine in people who have FMF are abdominal pain, diarrhea, nausea and vomiting.

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all of the possible side effects of Colchicine. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA.

How should I store Colchicine?

• Store Colchicine at room temperature between 68° and 77°F (20° to 25°C).
• Keep Colchicine in a tightly closed container.
• Keep Colchicine out of the light.

Keep Colchicine and all medicines out of the reach of children.
General Information about Colchicine

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use Colchicine for a condition for which it was not prescribed. Do not give Colchicine to other people, even if they have the same symptoms that you have. It may harm them. This Medication Guide summarizes the most important information about Colchicine. If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about Colchicine that is written for healthcare professionals.

What are the ingredients in Colchicine?

Active Ingredient: Colchicine

Inactive Ingredients: carnauba wax, FD&C blue #2, FD&C red #40, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, polydextrose, polyethylene glycol, pregelatinized starch, sodium starch glycolate, titanium dioxide, and triacetin.

Colchicine
0.6mg Tablets

INDICATIONS AND USAGE

Prophylaxis of Gout Flares:
Colchicine is 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.

Colchicine tablets are indicated in adults and children 4 years or older for treatment of familial Mediterranean fever (FMF).

DOSAGE AND ADMINISTRATION

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 are different for each indication and must be individualized.

The recommended dosage of Colchicine depends on the patient's age, renal function, hepatic function, and use of co-administered drugs.

Colchicine tablets are administered orally, without regard to meals.
Colchicine is not an analgesic medication and should not be used to treat pain from other causes.

Prophylaxis of Gout Flares:
The recommended dosage of Colchicine for prophylaxis of gout flares for adults and adolescents older than 16 years of age is 0.6 mg once or twice daily. The maximum recommended dose for prophylaxis of gout flares is 1.2 mg/day.

Treatment of Gout Flares:
The recommended dose of Colchicine for treatment of a gout flare is 1.2 mg (2 tablets) at the first sign of the flare followed by 0.6 mg (1 tablet) one hour later. Higher doses have not been found to be more effective. The maximum recommended dose for treatment of gout flares is 1.8 mg over a 1 hour period. Colchicine may be administered for treatment of a gout flare during prophylaxis at doses not to exceed 1.2 mg (2 tablets) at the first sign of the flare followed by 0.6 mg (1 tablet) one hour later. Wait 12 hours and then resume the prophylactic dose.

The recommended dosage of Colchicine for FMF in adults is 1.2 mg to 2.4 mg daily.

Colchicine should be increased as needed to control disease and as tolerated in increments of 0.3 mg/day to a maximum recommended daily dose. If intolerable side effects develop, the dose should be decreased in increments of 0.3 mg/day. The total daily Colchicine dose may be administered in one to two divided doses.

Prophylaxis and Treatment of Gout Flares:
Colchicine is not recommended for pediatric use in prophylaxis or treatment of gout flares.

FMF:
The recommended dosage of Colchicine for FMF in pediatric patients 4 years of age and older is based on age. The following daily doses may be given as a single or divided dose twice daily:

• Children 4 – 6 years: 0.3 mg to 1.8 mg daily
• Children 6 – 12 years: 0.9 mg to 1.8 mg daily
• Adolescents older than 12 years: 1.2 mg to 2.4 mg daily

Concomitant Therapy:
Co-administration of Colchicine with drugs known to inhibit CYP3A4 and/or P-glycoprotein (P-gp) increases the risk of colchicine-induced toxic effects (Table 1). If patients are taking or have recently completed treatment with drugs listed in Table 1 within the prior 14 days, the dose adjustments are as shown on the table below4.

Treatment of gout flares with Colchicine is not recommended in patients receiving prophylactic dose of Colchicine and CYP3A4 inhibitors.

Colchicine dosing must be individualized according to the patient's renal function [see Renal Impairment (8.6)].

Clcr in mL/minute may be estimated from serum creatinine (mg/dL) determination using the following formula:

Gout Flares:

Prophylaxis of Gout Flares:
For prophylaxis of gout flares in patients with mild (estimated creatinine clearance Clcr 50 – 80 mL/min) to moderate (Clcr 30 – 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.

Treatment of Gout Flares:
For treatment of gout flares in patients with mild (Clcr 50 – 80 mL/min) to moderate (Clcr 30 – 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, 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 2 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 (1 tablet). For these patients, the treatment course should not be repeated more than once every 2 weeks.

Treatment of gout flares with Colchicine is not recommended in patients with renal impairment who are receiving Colchicine for prophylaxis.

FMF:
Caution should be taken in dosing patients with moderate and severe renal impairment and in patients undergoing dialysis. For these patients, the dosage should be reduced. Patients with mild (Clcr 50 – 80 mL/min) and moderate (Clcr 30 – 50 mL/min) renal impairment should be monitored closely for adverse effects of Colchicine. Dose reduction may be necessary. For patients with severe renal failure (Clcr less than 30 mL/minute), start with 0.3 mg/day; any increase in dose should be done with adequate monitoring of the patient for adverse effects of colchicine. For patients undergoing dialysis, the total recommended starting dose should be 0.3 mg (half tablet) per day. Dosing can be increased with close monitoring. Any increase in dose should be done with adequate monitoring of the patient for adverse effects of colchicine.

Gout Flares
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.

Treatment of Gout Flares: For treatment 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. However, for the treatment of gout flares in patients with severe impairment while the dose does not need to be adjusted, but a treatment course should be repeated no more than once every 2 weeks. For these patients, requiring repeated courses for the treatment of gout flares, consideration should be given to alternate therapy.

Treatment of gout flares with Colchicine is not recommended in patients with hepatic impairment who are receiving Colchicine for prophylaxis.

FMF:
Patients with mild to moderate hepatic impairment should be monitored closely for adverse effects of colchicine. Dose reduction should be considered in patients with severe hepatic impairment.

DOSAGE FORMS AND STRENGTHS

0.6 mg tablets — purple capsule-shaped, film-coated with AR 374 debossed on one side and scored on the other side.

CONTRAINDICATIONS

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.

WARNINGS AND PRECAUTIONS

Fatal overdoses, both accidental and intentional, have been reported in adults and children who have ingested colchicine. Colchicine should be kept out of the reach of children.

Myelosuppression, leukopenia, granulocytopenia, thrombocytopenia, pancytopenia, and aplastic anemia have been reported with colchicine used in therapeutic doses.

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.

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 may potentiate the development of myopathy. Once colchicine is stopped, the symptoms generally resolve within 1 week to several months.

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 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.

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 1 hour) of Colchicine compared to 77% of patients taking a non-recommended high-dose (4.8 mg over 6 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 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 non-recommended high-dose colchicine regimen but did not occur in the recommended low-dose Colchicine regimen.

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.

The following adverse reactions have been reported with colchicine. These have been generally reversible upon temporarily interrupting treatment or lowering the dose of colchicine.

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

DRUG INTERACTIONS

Colchicine (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 is 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 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 toxicity should be evaluated promptly and, if toxicity is suspected, Colchicine 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.

USE IN SPECIFIC POPULATIONS

Pregnancy Category C
There are no adequate and well-controlled studies with colchicine in pregnant women. Colchicine crosses the human placenta. While not studied in the treatment of gout flares, data from a limited number of published studies found no evidence of an increased risk of miscarriage, stillbirth, or teratogenic effects among pregnant women using colchicine to treat familial Mediterranean fever (FMF). Although animal reproductive and developmental studies were not conducted with Colchicine, 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. Colchicine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

The effect of colchicine on labor and delivery is unknown.

Colchicine is excreted into human milk. Limited information suggests that exclusively breast-fed infants receive less than 10 percent of the maternal weight-adjusted dose. While there are no published reports of adverse effects in breast-feeding infants of mothers taking colchicine, colchicine can affect gastrointestinal cell renewal and permeability. Caution should be exercised and breast-feeding infants should be observed for adverse effects when Colchicine is administered to a nursing woman.

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. Gout is rare in pediatric patients, safety and effectiveness of colchicine in pediatric patients has not been established.

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.

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 Clcr 50 – 80 mL/min) to moderate (Clcr 30 – 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.

Treatment of Gout Flares:
For treatment of gout flares in patients with mild (Clcr 50 – 80 mL/min) to moderate (Clcr 30 – 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, 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 2 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 (1 tablet). For these patients, the treatment course should not be repeated more than once every 2 weeks.

FMF
Although, pharmacokinetics of colchicine in patients with mild (Clcr 50 – 80 mL/min) and moderate (Clcr 30 – 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 (Clcr less than 30 mL/minute) and end-stage renal disease requiring dialysis, Colchicine 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.

The clearance of colchicine may be significantly reduced and plasma half-life prolonged in patients with chronic hepatic impairment, compared to healthy subjects.

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.

Treatment of Gout Flares:
For treatment of gout flares in patients with mild to moderate hepatic function impairment, adjustment of the recommended Colchicine dose is not required, but patients should be monitored closely for adverse effects of Colchicine. 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 2 weeks. For these patients, requiring repeated courses for the treatment of gout flares, consideration should be given to alternate therapy.

FMF
In patients with severe hepatic disease, dose reduction should be considered with careful monitoring.

DRUG ABUSE AND DEPENDENCE

Tolerance, abuse, or dependence with colchicine has not been reported.

OVERDOSAGE

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 4-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 multi-organ failure and its consequences. Death is usually a result of respiratory depression and cardiovascular collapse. If the patient survives, recovery of multi-organ injury may be accompanied by rebound leukocytosis and alopecia starting about 1 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.

DESCRIPTION

Colchicine is an alkaloid chemically described as (S)N- (5,6,7,9-tetrahydro- 1,2,3, 10-tetramethoxy-9-oxobenzo [alpha] heptalen-7-yl) acetamide with a molecular formula of C22H25NO6 and a molecular weight of 399.4. The structural formula of colchicine is given below.

Colchicine occurs as a pale yellow powder that is soluble in water.

Colchicine tablets are supplied for oral administration as purple, film-coated, capsule-shaped tablets (0.1575" × 0.3030"), debossed with 'AR 374' on one side and scored on the other, containing 0.6 mg of the active ingredient colchicine USP. Inactive ingredients: carnauba wax, FD&C blue #2, FD&C red #40, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, polydextrose, polyethylene glycol, pregelatinized starch, sodium starch glycolate, titanium dioxide, and triacetin.

CLINICAL PHARMACOLOGY

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.

Absorption
In healthy adults, Colchicine is absorbed when given orally, reaching a mean Cmax of 2.5 ng/mL (range 1.1 to 4.4 ng/mL) in 1 to 2 hours (range 0.5 to 3 hours) after a single dose administered under fasting conditions.

Following oral administration of Colchicine given as 1.8 mg colchicine over 1 hour to healthy, young adults under fasting conditions, colchicine appears to be readily absorbed, reaching mean maximum plasma concentrations of 6.2 ng/mL at a median 1.81 hours (range: 1.0 to 2.5 hours). Following administration of the non-recommended high-dose regimen (4.8 mg over 6 hours), mean maximal plasma concentrations were 6.8 ng/mL, at a median 4.47 hours (range: 3.1 to 7.5 hours).

After 10 days on a regimen of 0.6 mg twice daily, peak concentrations are 3.1 to 3.6 ng/mL (range 1.6 to 6.0 ng/mL), occurring 1.3 to 1.4 hours post-dose (range 0.5 to 3.0 hours). Mean pharmacokinetic parameter values in healthy adults are shown in Table 5 below.

In some subjects, secondary colchicine peaks are seen, occurring between 3 and 36 hours post-dose and ranging from 39% to 155% of the height of the initial peak. These observations are attributed to intestinal secretion and reabsorption and/or biliary recirculation.

Absolute bioavailability is reported to be approximately 45%.

Administration of Colchicine with food has no effect on the rate of colchicine absorption, but did decrease the extent of colchicine by approximately 15%. This is without clinical significance.

Distribution
The mean apparent volume of distribution in healthy young volunteers was approximately 5 to 8 L/kg.

Colchicine binding to serum protein is low, 39 ± 5%, primarily to albumin regardless of concentration.

Colchicine crosses the placenta (plasma levels in the fetus are reported to be approximately 15% of the maternal concentration). Colchicine also distributes into breast milk at concentrations similar to those found in the maternal serum.

Metabolism
Colchicine is demethylated to two primary metabolites, 2-O-demethylcolchicine and 3-O-demethylcolchicine (2- and 3-DMC, respectively), and one minor metabolite, 10-O-demethylcolchicine (also known as colchiceine). In vitro studies using human liver microsomes have shown that CYP3A4 is involved in the metabolism of colchicine to 2- and 3-DMC. Plasma levels of these metabolites are minimal (less than 5% of parent drug).

Elimination/Excretion
In healthy volunteers (n=12) 40 – 65% of 1 mg orally administered colchicine was recovered unchanged in urine. Enterohepatic recirculation and biliary excretion are also postulated to play a role in colchicine elimination. Following multiple oral doses (0.6 mg twice daily), the mean elimination half-lives in young healthy volunteers (mean age 25 to 28 years of age) is 26.6 to 31.2 hours. Colchicine is a substrate of P-gp.

Extracorporeal Elimination: Colchicine is not removed by hemodialysis.

Special Populations
There is no difference between men and women in the pharmacokinetic disposition of colchicine.

Pediatric Patients:
Pharmacokinetics of colchicine was not evaluated in pediatric patients.

Elderly:
Pharmacokinetics of colchicine has not been determined in elderly patients. A published report described the pharmacokinetics of 1 mg oral colchicine tablet in four elderly women compared to six young healthy males. The mean age of the four elderly women was 83 years (range 75 – 93), mean weight was 47 kg (38 – 61 kg) and mean creatinine clearance was 46 mL/min (range 25 – 75 mL/min). Mean peak plasma levels and AUC of colchicine were two times higher in elderly subjects compared to young healthy males. However, it is possible that the higher exposure in the elderly subjects was due to decreased renal function.

Renal impairment: Pharmacokinetics of colchicine in patients with mild and moderate renal impairment is not known. A published report described the disposition of colchicine (1 mg) in young adult men and women with FMF who had normal renal function or end-stage renal disease requiring dialysis. Patients with end-stage renal disease had 75% lower colchicine clearance (0.17 vs 0.73 L/hr/kg) and prolonged plasma elimination half-life (18.8 hrs vs 4.4 hrs) as compared to subjects with FMF and normal renal function.

Hepatic impairment: Published reports on the pharmacokinetics of IV colchicine in patients with severe chronic liver disease, as well as those with alcoholic or primary biliary cirrhosis, and normal renal function suggest wide inter-patient variability. In some subjects with mild to moderate cirrhosis, the clearance of colchicine is significantly reduced and plasma half-life prolonged compared to healthy subjects. In subjects with primary biliary cirrhosis, no consistent trends were noted. No pharmacokinetic data are available for patients with severe hepatic impairment (Child-Pugh C).

Drug interactions:

In vitro drug interactions:
In vitro studies in human liver microsomes have shown that colchicine is not an inhibitor or inducer of activity.

In vivo drug interactions:
The effects of co-administration of other drugs with Colchicine on Cmax, AUC, and Cmin 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 Co-administration of Interacting Drugs.

Estrogen-containing oral contraceptives: In healthy female volunteers given ethinyl estradiol and norethindrone co-administered with Colchicine (0.6 mg b.i.d. × 14 days), hormone concentrations are not affected.

In healthy volunteers given theophylline co-administered with Colchicine (0.6 mg b.i.d. × 14 days), theophylline concentrations were not affected.

NONCLINICAL TOXICOLOGY

Carcinogenesis
Carcinogenicity studies of colchicine have not been conducted. Due to the potential for colchicine to produce aneuploid cells (cells with an unequal number of chromosomes), there is theoretically an increased risk of malignancy.

Mutagenesis
Colchicine was negative for mutagenicity in the bacterial reverse mutation assay. In a chromosomal aberration assay in cultured human white blood cells, colchicine treatment resulted in the formation of micronuclei. Since published studies demonstrated that colchicine induces aneuploidy from the process of mitotic nondisjunction without structural DNA changes, colchicine is not considered clastogenic, although micronuclei are formed.

Impairment of Fertility
No studies of colchicine effects on fertility were conducted with Colchicine. However, published nonclinical studies demonstrated that colchicine-induced disruption of microtubule formation affects meiosis and mitosis. Reproductive studies also reported abnormal sperm morphology and reduced sperm counts in males, and interference with sperm penetration, second meiotic division, and normal cleavage in females when exposed to colchicine. Colchicine administered to pregnant animals resulted in fetal death and teratogenicity. These effects were dose dependent, with the timing of exposure critical for the effects on embryofetal development. The nonclinical doses evaluated were generally higher than an equivalent human therapeutic dose, but safety margins for reproductive and developmental toxicity could not be determined.

Case reports and epidemiology studies in human male subjects on colchicine therapy indicated that infertility from colchicine is rare. 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.

CLINICAL STUDIES

The evidence for the efficacy of colchicine in patients with chronic gout is derived from the published literature. Two randomized clinical trials assessed the efficacy of colchicine 0.6 mg twice a day for the prophylaxis of gout flares in patients with gout initiating treatment with urate lowering therapy. In both trials, treatment with colchicine decreased the frequency of gout flares.

The efficacy of a low dosage regimen of oral colchicine (Colchicine total dose 1.8 mg over 1 hour) for treatment of gout flares was assessed in a multicenter, randomized, double-blind, placebo-controlled, parallel group, 1 week, dose comparison study. Patients meeting American College of Rheumatology criteria for gout were randomly assigned to three groups: high-dose colchicine (1.2 mg, then 0.6 mg hourly × 6 hours [4.8 mg total]); low-dose colchicine (1.2 mg, then 0.6 mg in 1 hour [1.8 mg total] followed by 5 placebo doses hourly); or placebo (2 capsules, then 1 capsule hourly × 6 hours). Patients took the first dose within 12 hours of the onset of the flare and recorded pain intensity (11-point Likert scale) and adverse events over 72 hours. The efficacy of colchicine was measured based on response to treatment in the target joint, using patient self assessment of pain at 24 hours following the time of first dose as recorded in the diary. A responder was one who achieved at least a 50% reduction in pain score at the 24-hour post-dose assessment relative to the pre-treatment score and did not use rescue medication prior to the actual time of 24-hour post-dose assessment.

Rates of response were similar for the recommended low-dose treatment group (38%) and the non-recommended high-dose group (33%) but were higher as compared to the placebo group (16%) as shown in Table 8.

Figure 1 below shows the percentage of patients achieving varying degrees of improvement in pain from baseline at 24 hours.

Figure 1 Pain Relief on Low and High Doses of Colchicine and Placebo (Cumulative)

The evidence for the efficacy of colchicine in patients with FMF is derived from the published literature. Three randomized, placebo-controlled studies were identified. The three placebo-controlled studies randomized a total of 48 adult patients diagnosed with FMF and reported similar efficacy endpoints as well as inclusion and exclusion criteria.

One of the studies randomized 15 patients with FMF to a 6-month crossover study during which 5 patients discontinued due to study non-compliance. The 10 patients completing the study experienced 5 attacks over the course of 90 days while treated with colchicine compared to 59 attacks over the course of 90 days while treated with placebo. Similarly, the second study randomized 22 patients with FMF to a 4-month crossover study during which 9 patients discontinued due to lack of efficacy while receiving placebo or study non-compliance. The 13 patients completing the study experienced 18 attacks over the course of 60 days while treated with colchicine compared to 68 attacks over the course of 60 days while treated with placebo. The third study was discontinued after an interim analysis of 6 of the 11 patients enrolled had completed the study; results could not be confirmed.

Open-label experience with colchicine in adults and children with FMF is consistent with the randomized, controlled trial experience, and was utilized to support information on the safety profile of colchicine and for dosing recommendations.

HOW SUPPLIED / STORAGE AND HANDLING

Colchicine, USP tablets 0.6 mg, are purple, film-coated, capsule-shaped tablets, debossed with 'AR 374' on one side and scored on the other side.

Store at 20° to 25°C (68° to 77°F).
[See USP Controlled Room Temperature]
Protect from light.

DISPENSE IN TIGHT, LIGHT-RESISTANT CONTAINER.

17 PATIENT COUNSELING INFORMATION

Patients should be advised to take Colchicine as prescribed, even if they are feeling better. Patients should not alter the dose or discontinue treatment without consulting with their doctor. If a dose of Colchicine is missed:

• For treatment of a gout flare when the patient is not being dosed for prophylaxis, take the missed dose as soon as possible.
• For treatment of a gout flare during prophylaxis, take the missed dose immediately, wait twelve hours, then resume the previous dosing schedule.
• For prophylaxis without treatment for a gout flare, or FMF, take the dose as soon as possible and then return to the normal dosing schedule. However, if a dose is skipped the patient should not double the next dose.

Instruct patient that fatal overdoses, both accidental and intentional, have been reported in adults and children who have ingested colchicine. Colchicine should be kept out of the reach of children.

Patients should be informed that bone marrow depression with agranulocytosis, aplastic anemia, and thrombocytopenia may occur with Colchicine.

Patients should be advised that many drugs or other substances may interact with Colchicine and some interactions could be fatal. Therefore, patients should report to their healthcare provider all of the current medications they are taking, and check with their healthcare provider before starting any new medications, particularly antibiotics. Patients should also be advised to report the use of non-prescription medication or herbal products. Grapefruit and grapefruit juice may also interact and should not be consumed during Colchicine treatment.

Patients should be informed that muscle pain or weakness, tingling or numbness in fingers or toes may occur with Colchicine alone or when it is used with certain other drugs. Patients developing any of these signs or symptoms must discontinue Colchicine and seek medical evaluation immediately.