Consumer medicine information

Colgout

Colchicine

BRAND INFORMATION

Brand name

Colgout

Active ingredient

Colchicine

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Colgout.

What is in this leaflet

This leaflet answers some common questions about Colgout. It does not contain all the available information. It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking Colgout against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.

What Colgout is used for

Colgout contains colchicine as the active ingredient. Colgout is used for the relief of pain in acute attacks of gout. It is not an analgesic and does not provide relief from other types of pain.

Colgout has a preventative effect that helps to reduce the incidence of acute attacks. It will not reduce the amount of uric acid in the body.

Colgout belongs to a group of medicines called antigout drugs.

Ask your doctor if you have any questions about why Colgout has been prescribed for you. Your doctor may have prescribed it for another reason.

This medicine is only available with a doctor's prescription.

There is no evidence that it is addictive.

Before you take it

When you must not take it

Do not take Colgout if you have an allergy to:

  • any medicine containing colchicine
  • any of the ingredients listed at the end of this leaflet.

Some of the symptoms of an allergic reaction may include shortness of breath, wheezing or difficulty breathing; swelling of the face, lips or tongue; skin rash, itching or hives.

Do not give this medicine to children. This medication may be dangerous to children. It is important that it is kept out of reach of children at all times.

Do not take Colgout if you have:

  • combined kidney and liver disease
  • serious kidney or liver disease
  • serious heart disease
  • severe stomach disorder
  • a blood disorder.

Do not take this medicine after the expiry date (EXP) printed on the pack. If you take this medicine after the expiry date has passed, it may not work as well.

Do not take this medicine if the bottle shows signs of having been tampered with.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Before you start to take it

Tell your doctor if you are allergic to any other medicines or any foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

  • stomach problems
  • kidney or liver disease
  • heart disease
  • alcoholism.

Tell your doctor if you are pregnant or plan to become pregnant. Colgout may affect your developing baby if you take it during pregnancy.

Tell your doctor if you are breast-feeding or plan to breastfeed. Your doctor will discuss the risks and benefits of you taking Colgout when breast-feeding.

If you have not told your doctor about any of the above, tell them before you start taking Colgout.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you buy without a prescription from your pharmacy, supermarket or health food shop.

Some medicines may interfere with Colgout. These include:

  • cyclosporin - a medicine used to suppress the immune system
  • erythromycin, clarithromycin and telithromycin - antibiotics used to treat bacterial infection
  • protease inhibitors, including atazanavir, indinavir, nelfinavir, ritonavir and saquinavir, used to treat HIV and other viral infections
  • ketoconazole and itraconazole, used to treat certain fungal infections
  • nefazodone, used to treat depression
  • acidifying and alkalinising agents, such as ammonium chloride, ascorbic acid (vitamin C), sodium bicarbonate
  • medicines to help you sleep
  • alcohol
  • NSAIDs or aspirin - anti-inflammatory drugs used to treat pain
  • medicines used to treat cancer including radiation therapy
  • vitamin B12
  • anticoagulants such as coumarin, heparin
  • antithyroid medicines.

These medicines may be affected by Colgout or may affect how well it works. You may need to take different amounts of your medicines or you may need to take different medicines. Your doctor or pharmacist has a more complete list of medicines to be careful with or avoid while taking Colgout.

Use in elderly or debilitated patients

Elderly or debilitated patients may be more sensitive to the effects or side effects of this medicine.

How to take it

Follow all directions given to you by your doctor carefully. They may differ from the information contained in this leaflet.

If you do not understand the instructions on the bottle, ask your doctor or pharmacist for help.

How much to take

Your doctor will tell you how much Colgout to take.

Do not take more than your doctor tells you to.

The maximum recommended dose for treatment of gout flares is 1.5mg over a one hour period.

Do not repeat the course within 3 days.

How to take it

Swallow the tablet whole with a full glass of water.

When to take it

Colgout may be taken before or after food.

How long to take it

Continue taking your medicine for as long as your doctor tells you. This will depend on your condition and your response to the treatment.

Colgout helps to control your condition but does not cure it.

Immediately stop taking Colgout at the first sign of stomach pain, nausea, vomiting or diarrhoea. Do this even if your symptoms have not been relieved.

If you forget to take it

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to.

Do not take a double dose to make up for the dose that you missed. This may increase the chance of you getting an unwanted side effect.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or the Poisons Information Centre (telephone 13 11 26) for advice, or go to Accident and Emergency at the nearest hospital if you think that you or anyone else may have taken too much Colgout. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

Symptoms of an overdose may include:

  • severe nausea, vomiting, stomach pain and diarrhoea
  • burning feeling or rawness in the mouth and throat
  • difficulty in breathing or swallowing
  • fever
  • muscle weakness
  • mental confusion, delirium, convulsions.

While you are taking it

Things you must do

Immediately stop taking Colgout at the first sign of stomach pain, nausea, vomiting or diarrhoea. Do this even if your symptoms have not been relieved. Remember to take note of the number of tablets you took before the onset of these symptoms so that you can take fewer tablets during subsequent attacks.

Tell any other doctors, dentists, and pharmacists who are treating you that you are taking this medicine, especially if you are being started on any new medicines.

Tell your doctor, surgeon or anaesthetist that you are taking Colgout if you are about to undergo surgery or an operation.

Tell your doctor immediately if you become pregnant while taking Colgout.

If you are about to have any blood tests, remind your doctor that you are taking Colgout. It may interfere with the results of some tests.

Keep all of your doctor's appointments so that your progress can be checked. Your doctor may do some tests from time to time to make sure the medicine is working and to prevent unwanted side effects.

Things you must not do

Do not take Colgout to treat any other complaints unless your doctor tells you to.

Do not give your medicine to anyone else, even if they have the same condition as you.

Things to be careful of

Be careful driving or operating machinery until you know how Colgout affects you.

Check with your doctor or pharmacist before drinking alcohol while you are taking Colgout. If you drink alcohol while taking this medicine, you may develop stomach problems.

This medication may be dangerous to children. It is important that it is kept out of reach of children at all times.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Colgout.

This medicine helps most people with gout, but it may have unwanted side effects in a few people. All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical treatment if you get some of the side effects.

If you are elderly you may have an increased chance of getting side effects.

Ask your doctor or pharmacist to answer any questions you may have.

Immediately stop taking Colgout at the first sign of stomach pain, nausea, vomiting or diarrhoea. Do this even if your symptoms have not been relieved.

The above list includes the more common side effects of your medicine.

Tell your doctor as soon as possible if you notice any of the following:

  • loss of appetite
  • loss of hair.

The above list includes more serious side effects which may require medical attention.

Tell your doctor immediately, or go to Accident and Emergency at your nearest hospital if you notice any of the following symptoms:

  • burning feeling in the stomach or throat
  • severe stomach pain, nausea, vomiting
  • severe diarrhoea with bloody or black tarry stools
  • itchy skin, skin rash, hives, unusual bleeding or bruising under the skin
  • difficulty in passing urine or blood in urine
  • confusion, convulsions
  • fever
  • muscle weakness
  • numbness or weakness in the fingers and toes.

These are all very serious side effects. You may need urgent medical attention or hospitalisation.

Tell your doctor or pharmacist if you notice anything else that is making you feel unwell. Some people may get other side effects while taking Colgout.

Some of these side effects (e.g. changes in thyroid function or in the blood) can only be found when your doctor does tests from time to time to check your progress.

Do not be alarmed by this list of possible side effects. You may not experience any of them.

After taking it

Storage

Keep your tablets in the bottle until it is time to take them. If you take the tablets out of the bottle they may not keep well.

Keep your tablets in a cool dry place where the temperature stays below 30°C.

Do not store Colgout or any other medicine in the bathroom or near a sink. Do not leave it on a window sill or in the car. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Disposal

If your doctor tells you to stop taking Colgout or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

Product description

What it looks like

Colgout tablets are round, white tablets embossed "C" on the upper side, and plain on the bottom face and are available in bottles of 30.

Ingredients

Active ingredient:

Each tablet contains 0.5 mg of colchicine.

Inactive ingredients:

  • magnesium stearate
  • lactose monohydrate
  • maize starch
  • povidone.

Sponsor

Aspen Pharmacare Australia Pty Limited
34-36 Chandos Street
St Leonards NSW 2065
Australia

Australian Registration Number:
AUST R 27909

This leaflet was prepared in August 2020

Published by MIMS October 2020

BRAND INFORMATION

Brand name

Colgout

Active ingredient

Colchicine

Schedule

S4

 

1 Name of Medicine

Colchicine.

2 Qualitative and Quantitative Composition

Each tablet contains 500 microgram of the active colchicine.

List of excipients with known effects.

Lactose monohydrate.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Round, white, slightly biconvex tablets embossed "C" on the upper side, and plain on the bottom face.

4 Clinical Particulars

4.1 Therapeutic Indications

Relief of pain in acute gout. Colchicine should not be used unless NSAIDs are contraindicated, or have been used and found to lack analgesic efficacy or to have unacceptable side effects in the individual patient.
Colchicine is not an analgesic and does not provide relief from other types of pain.

4.2 Dose and Method of Administration

Adults.

1 mg (2 tablets) at the first sign of the flare followed by 0.5 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 1.5 mg over a one hour period.
Do not repeat the course within 3 days.
If gastrointestinal side effects occur, discontinue immediately.
Colchicine may be taken with or without food.

Children.

The safety and effectiveness in this age group have not been established. See Section 4.3 Contraindications.

Elderly.

The elderly, even those with normal renal and hepatic function, may be more susceptible to cumulative toxicity with colchicine. As the elderly are more likely to have age related renal function impairment, caution and careful attention to dosage is recommended.
In those elderly patients who are small and slight (less than 50 kg) and those with renal or hepatic impairment, other treatments should be considered. If colchicine is used in these patients a maximum cumulative dose of 1.5 mg over three days should be observed.

Reduced hepatic and renal function.

A reduction in the size of individual doses, an increase in the interval between doses or a reduction in the total daily dosage may be necessary in patients with renal or hepatic impairment. Specifically, it is recommended that dosage be reduced by half if the patient's creatinine clearance is 50 mL per minute (0.83 mL per second) or less and that colchicine not be used at all if the patient's creatinine clearance is 10 mL per minute (0.17 mL per second) or less (see Section 4.3 Contraindications).
Furthermore, as renal dysfunction significantly reduces the clearance and prolongs the half-life of colchicine, close monitoring of the renally impaired patient is advised.

Duration of treatment.

Treatment with therapeutic doses of colchicine should be discontinued immediately, even if symptoms of the acute attack of gout have not been relieved, when gastrointestinal symptoms (abdominal pain, diarrhoea, nausea or vomiting) occur. The patient should be told to note the total dose taken prior to the appearance of these symptoms and during subsequent attacks of gout to use smaller doses.
Additional colchicine should not be administered for at least 3 days after a course of oral treatment.

Monitoring.

Complete blood counts are recommended at periodic intervals during long-term treatment due to the potential for bone marrow suppression while undergoing colchicine therapy.

4.3 Contraindications

Patients with combined hepatic and renal disease.
Renal or hepatic impairment who are taking a P-glycoprotein (P-gp) inhibitor or a strong CYP3A4 inhibitor.
Severe renal or hepatic impairment.
Patients with serious cardiac or gastrointestinal disorders.
Patients with blood dyscrasias.
Hypersensitivity to colchicine.
Children under 2 years of age.

4.4 Special Warnings and Precautions for Use

Use with caution in the following circumstances.

Colchicine can be fatal in overdose. There have been cases of fatality when colchicine was taken for a therapeutic purpose with doses as small as 6 or 7 mg.
Treatment with therapeutic doses should be discontinued immediately when gastrointestinal symptoms (abdominal pain, diarrhoea, nausea or vomiting) occur.
Colchicine should be given with care in geriatric or debilitated patients and to those with cardiac, renal or gastrointestinal disease. The drug should be used with caution in patients who may have early manifestations of these disorders.
The leukopenic and thrombocytopenic effects of colchicine may result in an increased incidence of microbial infection, delayed healing and gingival bleeding. If leukopenia or thrombocytopenia occur, dental work should be deferred until blood counts have returned to normal.

Use in hepatic impairment.

Colchicine should be given with care in patients with hepatic disease.

Use in renal impairment.

A reduction in the size of individual doses, an increase in the interval between doses or a reduction in the daily dosage may be necessary in patients with renal impairment.

Use in the elderly.

The elderly, even those with normal renal and hepatic function, may be more susceptible to cumulative toxicity with colchicine. As the elderly are more likely to have age related renal function impairment, the risk of myopathy and other toxic effects increases in patients receiving colchicine. Caution and careful attention to dosage is recommended.
In those elderly patients who are small and slight (less than 50 kg) and those with renal or hepatic impairment, other treatments should be considered. If colchicine is used in these patients a maximum cumulative dose of 1.5 mg over three days should be observed.

Paediatric use.

Safety and effectiveness in this age group have not been established. See Section 4.3 Contraindications.
Toxicity may occur at much lower doses in children than in adults. It is very important that this medicine is kept out of reach of children at all times.

Effects on laboratory tests.

Colchicine treatment has been shown to produce alterations to laboratory test results. The effects of potentially clinical significance include false positive test results for Red Blood Cells (RBC) and haemoglobin levels in diagnostic urine tests and interference of the Reddy, Jenkins and Thorn procedure when determining 17-hydroxycorticosteroid levels in urine. Furthermore, physiology/laboratory test values for serum alkaline phosphatase and aspartate aminotransferase (AST [SGOT]) values may be increased while the platelet count may be decreased.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Cyclosporin.

Caution is needed when colchicine and cyclosporin are used concomitantly as myopathies and rhabdomyolysis, especially in patients with renal impairment, may result through their use in combination. Increased blood cyclosporin concentrations and nephrotoxicity have developed in a renal transplant patient after the introduction of colchicine therapy.
Clinical evidence suggests that the concurrent use of colchicine and cyclosporin may develop pronounced side effects ranging from diarrhoea, elevation in liver enzymes, hyperbilirubinemia and elevations in serum creatinine levels. The possible mechanism of action is that the inhibition of p-glycoprotein by cyclosporin impairs the liver and renal excretion of the colchicine, causing elevated colchicine levels and possible cytotoxic drug accumulation.

Cytochrome P450 effects.

Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp). Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp. When clarithromycin and colchicine are administered together, inhibition of Pgp and/or CYP3A by clarithromycin may lead to increased exposure to colchicine. Patients should be monitored for clinical symptoms of colchicine toxicity.
The following CYP3A based drug interactions have been observed.

Strong CYP3A4 inhibitors.

Co-administration of colchicine with strong CYP3A4 inhibitors (atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir and telithromycin) may well result in increased colchicine plasma concentrations. Due to the potential risk of colchicine associated toxicity, such as neuromuscular adverse events and rhabdomyolysis, the concomitant use of colchicine with strong CYP3A4 inhibitors may require close monitoring. Use of colchicine capsules in conjunction with drugs that inhibit both P-gp and CYP3A4 is contraindicated in patients with renal or hepatic impairment.

Clarithromycin.

There have been postmarketing reports of colchicine toxicity with concomitant use of clarithromycin and colchicine, especially in the elderly, some of which occurred in patients with renal insufficiency. Deaths have been reported in some such patients.

Erythromycin.

Life threatening colchicine toxicity has been described after 2 weeks of concomitant erythromycin administration in a patient with hepatic and renal impairment.

Acidifying and alkalinising agents.

Colchicine is inhibited by acidifying agents such as ammonium chloride, ascorbic acid and acid phosphates and the action of colchicine is potentiated by alkalinising agents (e.g. sodium bicarbonate and potassium citrate).

CNS depressants.

Colchicine may increase the sensitivity to the CNS depressants such as the opiates, sedative hypnotics, benzodiazepines and ethanol as well as the response to sympathomimetic agents such as adrenaline, dopamine, dobutamine, isoprenaline and ephedrine may be enhanced when used concurrently with colchicine.

Alcohol.

The concurrent use of alcohol and orally administered colchicine increases the risk of gastrointestinal toxicity, especially in alcoholics. Furthermore, the alcohol increases blood uric acid concentrations that may decrease the efficacy of prophylactic gout therapy.

NSAIDs.

The concurrent use of phenylbutazone with colchicine may increase the risk of leukopenia, thrombocytopenia or bone marrow depression while the concurrent use of other NSAIDs with colchicine may increase the risk of gastrointestinal ulceration or haemorrhage.
NSAID induced inhibition of platelet aggregation may increase the risk of bleeding in areas other than the gastrointestinal tract should colchicine induced thrombocytopenia or clotting defects (with overdose) occur.

Antineoplastic agents.

The use of rapidly cytolytic antineoplastic agents with colchicine may increase serum uric acid concentrations and decrease the efficacy of prophylactic gout therapy.
The use of colchicine and radiation therapy may result in additive bone marrow depression. As a consequence, dosage reductions may be required when 2 or more bone marrow depressants, including radiation, are used concurrently or consecutively.
The leukopenic effects and/or thrombocytopenic effects of colchicine may be intensified with the concurrent or recent therapy with blood dyscrasia causing medications and bone marrow depressants. These medications are defined as those drugs causing unpredictable myelotoxicity that usually occurs in a minority of patients and is not dose-dependent, or as bone marrow depressants which produce a predictable dose-related myelotoxicity. Such medications include aldesleukin, amphotericin B lipid complex, anastrozole, angiotensin-converting enzyme (ACE) inhibitors, anti-inflammatory drugs, antithyroid agents, azathioprine, busulfan, carbamazepine, carboplatin, carmustine, chlorambucil, chloramphenicol, cisplatin, cladribine, clozapine, cyclophosphamide, cytarabine, dacarbazine, dactinomycin, dapsone, daunorubicin, didanosine, docetaxel, doxorubicin, etoposide, flecainide, flucytosine, fludarabine, fluorouracil, foscarnet, gamma and alpha interferon, ganciclovir, gemcitabine, gold compounds, hydroxyurea, idarubicin, ifosfamide, irinotecan, levamisole, lomustine, mechlorethamine, melphalan, mercaptopurine, methotrexate, mitomycin, mitoxantrone, paclitaxel, pegasparagase, penicillamine, pentamidine, phenothiazines, pimozide, primaquine, primidone, procainamide, procarbazine, pyrimethamine, rifampicin, sodium iodide I 131, strontium 89 chloride, sulfasalazine, sulfamethoxazole and trimethoprim, sulfonylurea antidiabetic agents, sulphonamides, thioguanine, thiotepa, thioxanthenes, ticlopidine, topotecan, tricyclic antidepressants, trimethoprim, valproic acid, vinblastine, vincristine, vinorelbine and zidovudine.
Furthermore, the possibility should be considered that colchicine, due to its potential to cause gastrointestinal haemorrhage, thrombocytopenia (with chronic use) and coagulation defects such as disseminated intravascular coagulation (with overdose), may cause an increased risk to patients receiving other medications that may impair blood clotting or cause haemorrhage. Such medications may include anticoagulants such as coumarin or indandione derivatives or other hypoprothrombinemia inducing medicines, heparin, thrombolytic agents, platelet aggregation inhibitors, other thrombocytopenic inducing medications and other medicines with the significant potential for causing gastrointestinal ulceration or haemorrhage.

Vitamin B12.

Colchicine has been shown to induce reversible malabsorption of vitamin B12, apparently by altering the function of ileal mucosa.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Animal studies of the effects of colchicine on fertility have not been evaluated. Colchicine arrests cell division in animals and plants and has adversely affected spermatogenesis in humans and in some animal species under certain conditions.
(Category D)
Cell division in animals can be arrested by colchicine. Colchicine should be avoided in pregnancy.
Reproductive toxicity studies of colchicine have not been evaluated. In published studies, colchicine has been shown to be teratogenic in mice given doses of 0.5 mg/kg and has produced foetotoxic and teratogenic effects in hamsters given 10 mg/kg. In other studies, colchicine was embryotoxic in rabbits and cattle but not in monkeys. The possibility of such effects in humans has been reported. However, there are no adequate and well-controlled studies in pregnant women or in men conceiving children while taking colchicine.
Colchicine crosses the placental barrier and was present in a sample of umbilical cord blood taken from a newborn child.
Therefore, if this drug is used during pregnancy, or if the patient becomes pregnant while taking it, the woman should be told of the potential hazard to the foetus.
It is recommended that breast-feeding should generally be avoided while the patient is taking colchicine.
Colchicine has been shown to be highly excreted into human breast milk and the concentration in the breast milk is similar to that found in the corresponding serum.
Peak concentrations of 1.2 to 2.5 nanogram per mL (< 0.001 micromole per litre) have been measured 40 to 50 minutes after administration of a 0.6 mg dose to a patient receiving long-term therapy with 0.6 mg twice a day. No adverse effects were apparent in the breastfed infant during the first 6 months of life.
Animal studies have not been performed to assess whether treatment of the mother with colchicine during lactation affects the newborn infant.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.8 Adverse Effects (Undesirable Effects)

Blood disorders.

Colchicine has been associated with the induction of several clinically significant haematological conditions. These conditions are typically related to overdosage and include anaemia, leukopenia, neutropenia, thrombocytopenia, nonthrombocytopenia purpura, agranulocytosis, pancytopenia and aplastic anaemia. However, such conditions are also related to long-term therapy with colchicine. Periodic blood counts should be performed during long-term therapy.
Blood dyscrasias have been reported following normal oral doses while deaths resulting from colchicine induced neutropenia have also been described in the literature.

Body as a whole.

Reactions to colchicine appear to be dose related. Hypothyroidism, prostration and reversible muscular weakness have been reported with colchicine therapy. Losses of body and scalp hair, loss of appetite and myopathy have been reported with prolonged administration of colchicine. Myopathy is more likely to occur in patients with impaired renal or hepatic function who are receiving long-term treatment with prophylactic doses of colchicine. This condition is characterised by proximal muscle weakness, spontaneous activity in an electromyelogram and elevated creatinine kinase levels.
Rhabdomyolysis has also been reported.

Cardiovascular.

Prolonged or toxic levels of colchicine may cause generalised vascular damage.

Eye disorders.

Colchicine may delay or prevent corneal wound healing. Cases of corneal ulcers refractory to conventional treatment and delayed corneal wound healing following strabismus surgery have been reported while the patients were receiving oral colchicine therapy. Discontinuation of colchicine therapy resulted in satisfactory wound healing within several days.

Gastrointestinal.

The most common side effects are gastrointestinal (e.g. nausea, vomiting, abdominal pain, diarrhoea), particularly in the presence of peptic ulcer or spastic colon. These symptoms present approximately 8 to 12 hours after oral administration in 80% of patients, especially when maximal doses are used. Therapy should be discontinued at the onset of gastrointestinal intolerance in order to avoid serious toxicity, regardless of whether joint pain has been relieved. Further treatment should be postponed for at least 3 days when gastrointestinal symptoms are encountered.
Steatorrhoea has been reported in a patient undergoing colchicine therapy who subsequently underwent surgery that revealed a reticulum cell sarcoma.
Colchicine produces a reversible malabsorption syndrome by disrupting the intestinal mucosal function and in particular, the absorption of vitamin B12 may be impaired by long-term therapy.
At toxic doses, colchicine may cause severe diarrhoea that may be haemorrhagic and can lead to metabolic acidosis, dehydration, hypotension and shock. Antidiarrhoeal agents may be required for the treatment of diarrhoea resulting from colchicine therapy. Paralytic ileus and stomatitis have also been reported.

Genitourinary.

Reversible azoospermia and oligospermia has been attributed to colchicine therapy. Other studies have suggested reduction in sperm motility and abnormal sperm penetration assay results.

Hepatobiliary effects.

Bladder spasm has been reported while anuria, haematuria and oliguria have been associated with prolonged colchicine therapy. At toxic doses, colchicine may cause renal damage which results in haematuria and oliguria.
Colchicine may also cause increased serum concentrations of alkaline phosphatase.

Hypersensitivity and skin.

Nonthrombocytopenic purpura, rashes, urticaria, dermatoses and dermatitis have been reported and very rarely, hypersensitivity including angioedema.

Neurological.

Colchicine induced myoneuropathy may occur during normal therapy. Although both skeletal muscles and peripheral nerves are affected, myopathy is most prominent and associated axonal neuropathy is mild. In most cases of myoneuropathy, symptoms have manifested after several years of therapy. Colchicine may also cause peripheral neuropathy (numbness of fingers and toes) with prolonged administration.

Respiratory.

A colchicine related death through the development of Adult Respiratory Distress Syndrome has been reported.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

Symptoms.

A latent period of 2 to 12 hours occurs between overdose and the onset of gastrointestinal symptoms.
The first signs of toxicity may be a feeling of burning and rawness in the mouth and throat and difficulty in swallowing. These symptoms are followed by severe nausea, vomiting, abdominal pain, haemorrhagic gastroenteritis, with resulting electrolyte abnormalities, volume depletion and hypotension.
The second phase consists of multisystem failure and generally occurs at 24 to 72 hours post ingestion. Effects include CNS toxicity, bone marrow depression, hepatocellular damage, muscle damage, respiratory distress, myocardial injury and renal damage. Multiple organ failure caused by tissue damage including bone marrow hypoplasia is likely to be followed by agranulocytosis, leukopenia, thrombocytopenia and disseminated intravascular coagulation. In some patients, disseminated intravascular coagulation may be the first haematological sign of toxicity, with the most severe coagulopathy occurring about 25 hours following the administration of a large overdose. Leucopenia may persist for several days followed by leucocytosis with numerous metamyelocytes and myelocytes. Other haematological manifestations of colchicine poisoning include granulocytopenia, immature leukocytes, pancytopenia, anaemia with anisocytosis, polychromasia and basophilic stippling.
Cerebral oedema and CNS toxicity are also associated with acute colchicine toxicity and may be characterised by marked muscular weakness and the development of ascending CNS paralysis with the patient remaining conscious. Mental confusion, delirium, seizures and convulsions may occur as a result of CNS toxicity. There may be a loss of deep tendon and Achilles tendon reflexes, and Babinski's reflex may be elicited.
A fever may develop; sepsis is a well recognised complication and should not be ruled out.
Death may occur as a result of respiratory depression, cardiovascular collapse, or sepsis.
In surviving patients, alopecia, rebound leucocytosis and stomatitis may occur about 10 days after the acute overdose.
Severe toxicity and death have been associated with oral doses exceeding 0.5 mg/kg. The lethal dose varies. While it appears to be about 40 mg in adults with normal renal function, a fatal dose of 7 mg has been recorded.

Treatment.

When treating colchicine overdosage or acute poisoning, patients should be carefully monitored for at least 12 hours to take into account the delayed onset of symptoms.
There is no specific antidote for colchicine poisoning. Activated charcoal should be administered, preferably within one hour of ingestion. Repeated oral charcoal dosing (every 2 to 6 hours), administered as a slurry, may enhance total body clearance and elimination, but has not been shown to affect outcome and is not routinely recommended. Consider administration of more than one dose of activated charcoal in patients with moderate to severe poisoning or very large ingestions, and those with clinical deterioration or rising levels despite initial decontamination.
Measures to prevent shock should be taken and diarrhoea should not be treated as this is the main route of elimination.
Other treatment is symptomatic and supportive with attention being given to the control of respiration, maintenance of blood pressure and the circulation, and correction of fluid and electrolyte imbalance.
Analgesics with or without atropine may relieve the abdominal pain, but monitor carefully for possible paralytic ileus.
A benzodiazepine such as diazepam may be given to control convulsions.
Both acute and chronic toxicity may lead to bone marrow depression. Isolate patient if there is evidence of bone marrow depression.
Due to the large apparent volume of distribution of colchicine, haemodialysis and peritoneal dialysis are not recommended.
Monitoring should include haemodynamic, cardiac and respiratory status and blood electrolytes. In some circumstances, prolonged observation may be recommended as the most severe toxic effects may not appear until 24 hours after ingestion of an acute dose.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

The exact mechanism of action of colchicine in gout is not completely understood. Colchicine decreases leucocyte chemotaxis and phagocytosis and thereby inhibits the formation and release of a chemotactic glycoprotein that is produced during the phagocytosis of urate crystals. Colchicine also inhibits urate crystal deposition, which is enhanced by a low pH in the tissues, probably by inhibiting oxidation of glucose and subsequent lactic acid production in leucocytes.
Colchicine is not an analgesic, though it relieves pain in acute attacks of gout. It is not a uricosuric agent and will not prevent progression of gout to chronic gouty arthritis. It does have a prophylactic, suppressive effect that helps to reduce the incidence of acute attacks and to relieve the residual pain and mild discomfort that patients with gout occasionally feel.
Colchicine inhibits cell division in the metaphase by interfering with the mitotic spindle.
Colchicine has other pharmacological actions in animals; it alters neuromuscular function, intensifies gastrointestinal activity by neurogenic stimulation, increases sensitivity to central depressants, heightens response to sympathomimetic compounds, depresses the respiratory centre, constricts blood vessels, causes hypertension by central vasomotor stimulation and lowers body temperature.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

Absorption.

Following oral administration, Colchicine is absorbed from the gastrointestinal tract and reaches peak plasma concentration within 2 hours. It is partially deacetylated in the liver and the unchanged drug and its metabolites are excreted in the bile and undergo intestinal reabsorption. Recycling of the drug probably accounts for the extensive intestinal manifestations which occur in colchicine poisoning.

Distribution.

In plasma, colchicine possesses a low to moderate protein binding (30 to 50%) and after reabsorption, is rapidly removed from the plasma and distributed to various tissues. The oral bioavailability of colchicine is between 25 to 50%. Colchicine is found in high concentrations in leucocytes, kidneys, the liver and spleen and as a consequence, accumulation in these tissues may lead to toxicity. Colchicine is rapidly distributed to peripheral leucocytes and concentrations in these cells may exceed those in plasma.

Metabolism and excretion.

Colchicine is partly acetylated in the liver and is slowly metabolised in other tissues.
The majority of the drug and its metabolites are excreted primarily in the faeces while 10 to 20% is excreted in urine. Renal elimination may increase in patients with hepatic impairment. Due to the high levels of tissue uptake of colchicine, only 10% of a single dose is eliminated in the first 24 hours. Consequently, the elimination of colchicine from the body may continue for 10 days or more after the cessation of treatment.
Following a single 1 mg oral dose, the mean half-life of colchicine was determined to be 4.4 hours in patients with normal renal function while the mean half-life in patients with renal dysfunction was 18.8 hours. Similarly, a single oral dose of 1 mg produces peak serum concentrations of between 3.9 to 11 nanogram/mL within 2 hours.
The initial response to oral colchicine occurs between 12 to 24 hours and the peak response is expected within 48 to 72 hours.

5.3 Preclinical Safety Data

Genotoxicity.

Mutagenicity studies of colchicine have not been evaluated. Colchicine is a known genotoxin, causing gene mutations, DNA damage and chromosomal damage in several in vitro and in vivo assays.

Carcinogenicity.

Animal studies have not been performed to assess the potential carcinogenic effect of colchicine. Since colchicine is an established mutagen, its ability to act as a carcinogen must be suspected and treatment with Colgout should involve a weighing of the benefit vs risk when long-term administration is being considered.

6 Pharmaceutical Particulars

6.1 List of Excipients

Each tablet contains the following inactive ingredients: magnesium stearate, lactose monohydrate, maize starch and povidone.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 30°C. Protect from light.

6.5 Nature and Contents of Container

HDPE bottle containing 30 tablets.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Colchicine occurs as pale yellow, amorphous scales or powder and darkens on exposure to light. Colchicine is soluble in water, freely soluble in alcohol and chloroform and slightly soluble in ether.
A phenanthrene derivative, colchicine is an alkaloid obtained from various species of Colchicum. The chemical name for colchicine is (S)-N-(5,6,7,9-tetrahydro-1,2,3,10- tetramethoxy-9-oxobenzo [α] heptalen-7-yl) acetamide (molecular weight 399.4).

Chemical structure.


CAS number.

64-86-8.

7 Medicine Schedule (Poisons Standard)

S4.

Summary Table of Changes