Colchicine
From DrugPedia: A Wikipedia for Drug discovery
Pronouncation: (KOHL-chih-seen)
Class: Agent for gout
Trade Names:
Colchicine - Tablets 0.6 mg
Contents |
[edit] Pharmacology
Inhibits inflammation and reduces pain and swelling associated with gouty arthritis.
[edit] Pharmacokinetics
Absorption
Rapidly absorbed. T max is 0.5 to 2 h.
Distribution
Large amounts present in bile and intestinal secretions. High concentrations also found in kidney, liver, and spleen. About 50% protein bound. Vd is 1 to 3 L/kg.
Metabolism
Undergoes enterohepatic recirculation. Deacetylated primarily by the liver.
Elimination
Plasma t ½ to 10 to 60 min. Excreted via biliary and renal routes; 10% to 20% excreted unchanged in urine.
[edit] Indications and Usage
Treatment and relief of pain in attacks of acute gouty arthritis; regular prophylaxis between attacks and is often effective in aborting an attack when taken at the first sign of articular discomfort.
Unlabeled Uses
Familial Mediterranean fever; hepatic cirrhosis; primary biliary cirrhosis; treatment of Behcet disease; scleroderma; Sweet syndrome
Contraindications
Serious GI, renal, hepatic, or cardiac disorders; blood dyscrasias.
[edit] Dosage and Administration
Acute Gouty Arthritis
Adults
Initial dose (give at first sign of attack) PO 1.2 mg; then 0.6 every h or 1.2 mg every 2 h until pain is relieved or diarrhea ensues. Total dose is usually 4 to 8 mg. Wait 3 days before initiating a second course of therapy.
Prophylaxis
Adults
PO 0.6 mg/day for 3 to 4 days/wk if fewer than 1 attack/yr; if more than 1 attack/yr, 0.6 mg/day. Severe cases may require 1.2 to 1.8 mg/day.
Surgical Patients
Adults
PO 0.6 mg 3 times daily for 3 days before and 3 days after surgery.
[edit] Storage/Stability
Oral
Store tablets in airtight, light-resistant container.
Drug Interactions
None well documented.
Laboratory Test Interactions
May cause false-positive results in urine tests for RBCs and hemoglobin.
[edit] Adverse Reactions
Dermatologic
Dermatoses; purpura; alopecia.
GI
Nausea; vomiting; diarrhea; abdominal pain.
Hematologic
Bone marrow depression with aplastic anemia; agranulocytosis, leukopenia or thrombocytopenia (long-term therapy).
Hepatic
Elevated alkaline phosphatase and AST.
Miscellaneous
Reversible azoospermia; myopathy; peripheral neuritis.
[edit] Precautions
Monitor
Blood counts
Check blood counts periodically in patients undergoing long-term therapy.
Toxicity signs
Assess for signs of toxicity (eg, abdominal pain, alopecia, nausea, vomiting, diarrhea, myopathy, peripheral neuritis). Notify health care provider immediately if these signs occur.
Uric acid/Creatinine
Monitor serum uric acid and creatinine throughout therapy.
Pregnancy
Category C (oral).
Lactation
Undetermined.
Children
Safety and efficacy not established.
Elderly
Administer with great caution to elderly and debilitated patients.
Hepatic Function
Increased colchicine toxicity may occur.
GI reactions
Drug may cause nausea, vomiting, diarrhea, and abdominal pain that may aggravate pre-existing peptic ulcer or spastic colon. Discontinue drug if these symptoms appear.
Myopathy and neuropathy
Myoneuropathy may occur and cause weakness in patients with impaired kidney function; serum creatine kinase may be elevated. Usually resolves in 3 to 4 wk after drug withdrawal.
Vitamin B 12 malabsorption
Colchicine induces reversible malabsorption of vitamin B 12 with long-term use.
[edit] Overdosage
Symptoms
Nausea, severe abdominal pain, vomiting, diarrhea, shock, ST segment elevation, paralysis, respiratory failure, liver damage, renal failure, leukopenia, thrombocytopenia, coagulopathy, alopecia, stomatitis.
[edit] Patient Information
- Instruct patient to take colchicine regularly to prevent acute attacks.
- Instruct patient not to exceed 8 mg in course of therapy for acute attack. To minimize cumulative toxicity, patient should wait 3 days before starting second course.
- Advise patient with gout to drink at least 2,000 mL of fluid daily, unless contraindicated.
- Reinforce health care provider's instructions about weight loss, diet, and alcohol intake.
- Advise patient to have extra supply of drug on hand in case health care provider gives instructions to increase dosage.
- Instruct patient to stop taking drug if nausea, vomiting, diarrhea, or abdominal pain occurs, especially if patient has history of spastic colon or ulcers.
