Colchicine
Mechanism :
The exact mechanism of action of colchicine is not completely known, but it involves a reduction in lactic acid production by leukocytes, which results in a decrease in uric acid deposition, and a reduction in phagocytosis, with abatement of the inflammatory response.
Indication :
- Familial Mediterranean fever
- Amyloidosis
- Gouty inflammation
Contraindications :
Should not be used in patients with blood dyscrasias of any nature. Colchicine should be used with caution in patients with decreased renal function as they are at increased risk of neuromuscular toxicity and bone marrow dysplasia. Use with caution in patients with gastrointestinal, hepatic or cardiac disease. Periodic blood counts should be performed in patients receiving long-term colchicine.
Dosing :
Gout:
<16 years:
Not recommended.
>16 years:
Acute gout: 1.2 mg (Oral) at first sign of flare, followed by 0.6 mg 1 hour later: Maximum dose: 1.8 mg in 1 hour period.
Prophylaxis:
0.6 mg (Oral) once or twice daily (Maximum: 1.2 mg/day); wait for 12 hours after gout flare to continue prophylaxis.
Familial Mediterranean Fever:
<4 years:
Safety and efficacy not established.
4-6 years:
0.3-1.8 mg/day PO as a single daily or 12 hourly divided doses.
6-12 years:
0.9-1.8 mg/day PO as a single daily or 12 hourly divided doses.
>12 years:
1.2-2.4 mg/day PO as a single daily or 12 hourly divided doses.
Adverse Effect :
Nausea, vomiting, cramps, abdominal pain, bone marrow depression, peripheral neuritis, myopathy, loss of hair, and reversible azoospermia.
Interaction :
Cyclosporine: Colchicine may increase cyclosporin levels.
Vitamin B12: Absorption of it from the gastrointestinal tract may be reduced.
Erythromycin: May induce colchicine toxicity if the two drugs are used together.
CNS Depressants: Colchicine may increase sensitivity to the CNS depressants.
Sympathomimetic Agents: Response to sympathomimetic agents may be enhanced by colchicine.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Dose as in normal renal function |
| <10 | 500 mcg 3–4 times a day; maximum total dose of 3 mg |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Not dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
| CAV/VVHD | Unknown dialysability. Dose as in normal renal function |
Hepatic Dose :
Mild to Moderate hepatic impairment: Use with caution.
Severe hepatic impairment: Use is contraindicated.