Colchicine is not a pain reliever and cannot be used to treat pain that is not caused by gout or FMF. Colchicine is in a class of medications called anti-gout agents. It works by stopping the natural processes that cause swelling and other symptoms of gout and FMF.
An acute attack of gout apparently occurs as a result of an inflammatory reaction to crystals of monosodium urate that are deposited in the joint tissue from hyperuric body fluids; the reaction is aggravated as more urate crystals accumulate. Leukocytes migrate to the sites where urate crystals have been deposited and try to engulf the crystals by phagocytosis. As a result lactic acid and proinflammatory enzymes are released which cause inflammation with severe pain, redness, and swelling of the affected joint. Lactic acid favors a local decrease in pH that enhances uric acid deposition. Colchicine inhibits the phagocytosis of uric acid by leukocytes & also diminishes the lactic acid production directly. Thus interrupts the cycle of urate crystal deposition and inflammatory response that sustains the acute attack of gout.
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 after a single dose administered under fasting conditions. The mean apparent volume of distribution is approximately 5 to 8 L/kg. Colchicine binding to serum protein is low (39 ± 5%), primarily to albumin regardless of concentration. CYP3A4 is involved in the metabolism of Colchicine to 2-O-demethylcolchicine and 3-O-demethylcolchicine. Plasma levels of these metabolites are minimal (less than 5% of parent drug). Following multiple oral doses (0.6 mg twice daily), the mean elimination half-life is 26.6 to 31.2 hours.
Acute gout BY MOUTH Adult: 500 micrograms 2-4 times a day until symptoms relieved, maximum 6mg per course, do not repeat course within 3 days. Short-term prophylaxis during initial therapy with allopurinol and uricosuric drugs BY MOUTH Adult: 500 micrograms twice daily Prophylaxis of familial Mediterranean fever (recurrent polyserositis) BY MOUTH Adult: 0.5-2 mg once daily
Co-administration of P-gp and/or CYP3A4 inhibitors (e.g., clarithromycin or cyclosporine) have been demonstrated to alter the concentration of Colchicine
Blood disorders Cardiac disease . elderly . gastro-intestinal disease
Common or very common Abdominal pain . nausea . vomiting Rare Alopecia . blood disorders with prolonged treatment . inhibition of spermatogenesis . myopathy . peripheral neuritis Frequency not known Excessive doses may cause profuse diarrhoea . gastrointestinal haemorrhage . hepatic damage . rash . renal damage
PREGNANCY Avoid?teratogenicity in animal studies. BREAST FEEDING Present in milk but no adverse effects reported. Manufacturers advise caution.
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.
Store below 30°C temperature. Protect from light and moisture. Keep the medicine out of reach of children.
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