Class: Antigout
Dosage Forms. Tablet: 0.6 mg
Common FDA Label Indication, Dosing, and Titration.
1. Gout, acute: 1.2 mg po at the first sign of a flare followed by 0.6 mg 1 h later; max 1.8 mg over 1 h
2. Gout, prophylaxis: 0.6 mg po daily to bid, max of 1.2 mg/d or onset of diarrhea
3. Familial Mediterranean fever: Children 4-6 y, 0.3-1.8 mg po daily; Children 6-12 y, 0.9-1.8 mg po daily; Children 12 y and older and Adults, 1.2-2.4 mg po daily, increase or decrease dose in increments of 0.3 mg/d
Off-Label Uses.
1. Amyloidosis: 0.6 mg po bid
2. Constipation: 0.6 mg po q30 min until onset of diarrhea
MOA. Exact mechanism unknown. In patients with gout, may interrupt the cycle of monosodium urate crystal deposition in joint tissues and the resultant inflammatory response that initiates and sustains an acute attack. 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 leukocytes.
Drug Characteristics: Colchicine
Medication Safety Issues: Colchicine
Drug Interactions: Colchicine
Adverse Reactions: Colchicine
Efficacy Monitoring Parameters. Resolution of clinical signs and symptoms of gout (pain, stiffness).
Toxicity Monitoring Parameters. CBC, alkaline phosphatase at baseline and periodically during treatment. Instruct patients to discontinue the medication immediately and seek medical attention if signs and symptoms of agranulocytosis (severe neutropenia), or myotoxicity (including rhabdomyolysis).
Key Patient Counseling Points. Instruct patient on appropriate dosing strategy for gout flares (dosing to symptom relief or onset of adverse effects, particularly diarrhea).
Clinical Pearls. Colchicine is a natural alkaloid found in plants such as the autumn crocus (Colchicum autumnale) and glory lily (Gloriosa superba).