Colchicine
Colchicine
Colchicine
( KOHL-chih-seen)
Pregnancy Category: C (oral use); D (parenteral use) (Rx)

Classification: Antigout agent

Action/Kinetics: Colchicine is not uricosuric. It may reduce the crystal-induced inflammation by reducing lactic acid production by leukocytes (resulting in a decreased deposition of sodium urate), by inhibiting leukocyte migration, and by reducing phagocytosis. May also inhibit the synthesis of kinins and leukotrienes. t 1/2, plasma: 10-60 min. Onset, IV: 6-12 hr; PO: 12 hr. Time to peak levels, PO: 0.5-2 hr. It concentrates in leukocytes (t 1/2, about 46 hr). Metabolized in the liver and mainly excreted in the feces with 10%-20% excreted unchanged through the urine.

Uses: Prophylaxis and treatment of acute attacks of gout. Investigational: To slow progression of chronic progressive multiple sclerosis, to decrease frequency and severity of fever and to prevent amyloidosis in familiar Mediterranean fever, primary biliary cirrhosis, hepatic cirrhosis, adjunct in the treatment of primary amyloidosis, Behcet's disease, pseudogout due to chondrocalcinosis, refractory idiopathic thrombocytopenic purpura, progressive systemic sclerosis, dermatologic disorders including dermatitis herpetiformis, psoriasis, palmoplantar pustulosis, and pyoderma associated with Crohn's disease.

Contraindications: Blood dyscrasias. Serious GI, hepatic, cardiac, or renal disorders.

Special Concerns: Use with caution during lactation. Dosage has not been established for children. Geriatric clients may be at greater risk of developing cumulative toxicity. Use with extreme caution for elderly, debilitated clients, especially in the presence of chronic renal, hepatic, GI, or CV disease. May impair fertility.

Side Effects: The drug is toxic; thus clients must be carefully monitored. GI: N&V;, diarrhea, abdominal cramping. Hematologic: Aplastic anemia, agranulocytosis or thrombocytopenia following long-term therapy. Miscellaneous: Peripheral neuritis, purpura, myopathy, neuropathy, alopecia, reversible azoospermia, dermatoses, hypersensitivity, thrombophlebitis at injection site (rare), liver dysfunction. If such symptoms appear, discontinue drug at once and wait at least 48 hr before reinstating drug therapy.

Laboratory Test Alterations: Alters liver function tests. Alkaline phosphatase, AST. False + for hemoglobin or RBCs in urine.

Overdose Management: Symptoms (Acute Intoxication): Characterized at first by violent GI tract symptoms such as N&V;, abdominal pain, and diarrhea. The latter may be profuse, watery, bloody, and associated with severe fluid and electrolyte loss. Also, burning of throat and skin, hematuria and oliguria, rapid and weak pulse, general exhaustion, muscular depression, and CNS involvement. Death is usually caused by respiratory paralysis. Treatment (Acute Poisoning): Gastric lavage, symptomatic support, including atropine and morphine, artificial respiration, hemodialysis, peritoneal dialysis, and treatment of shock.

Drug Interactions: Acidifying agents / Inhibit the action of colchicine Alkalinizing agents / Potentiate the action of colchicine CNS depressants / Clients on colchicine may be more sensitive to CNS depressant effect of these drugs Sympathomimetic agents / Enhanced by colchicine Vitamin B ₁₂ / Colchicine may interfere with absorption from the gut

How Supplied: Injection: 0.5 mg/ml; Tablet: 0.5 mg, 0.6 mg

Dosage
?Tablets Acute attack of gout.
Adults, initial: 1-1.2 mg followed by 0.5-1.2 mg q 1-2 hr until pain is relieved or nausea, vomiting, or diarrhea occurs. Total amount required: 4-8 mg.
Prophylaxis for gout.
Adults: 0.5-0.65 mg/day for 3-4 days a week if the client has less than one attack per year or 0.5-0.65 mg/day if the client has more than one attack per year.
Prophylaxis for surgical clients.
Adults: 0.5-0.65 mg t.i.d. for 3 days before and 3 days after surgery.
?IV Only Acute attack of gout.
Adults, initial: 2 mg; then, 0.5 mg q 6 hr until pain is relieved; give no more than 4 mg in a 24-hr period. Some physicians recommend a single IV dose of 3 mg while others recommend no more than 1 mg for the initial dose, followed by 0.5 mg once or twice daily, if needed. If pain recurs, 1-2 mg/day may be given for several days; however, colchicine should not be given by any route for at least 7 days after a full course of IV therapy (i.e., 4 mg).
Prophylaxis or maintenance of recurrent or chronic gouty arthritis.
0.5-1 mg 1-2 times/day. However, PO colchicine is preferred (usually with a uricosuric drug).