What is the recommended dose of colchicine (Colcrys) when starting allopurinol (Zyloprim) for gout management?

Colchicine Dosing When Starting Allopurinol

When initiating allopurinol for gout, start colchicine prophylaxis at 0.5-1 mg daily and continue for 3-6 months, with ongoing evaluation to extend prophylaxis if flares persist.

Recommended Prophylactic Dose

• Start colchicine at 0.5 mg daily, which can be increased to 1 mg daily if tolerated 1
• The American College of Rheumatology strongly recommends concomitant anti-inflammatory prophylaxis (colchicine, NSAIDs, or prednisone/prednisolone) when initiating any urate-lowering therapy 2
• The FDA-approved dosing for gout flare prophylaxis is 0.6 mg once or twice daily, with a maximum of 1.2 mg/day 3
• EULAR guidelines support colchicine 0.5-1 mg daily during the first months of urate-lowering therapy 2

Duration of Prophylaxis

• Continue prophylaxis for 3-6 months rather than less than 3 months 2
• Do not stop prophylaxis abruptly at 6 months without assessing whether the patient has achieved serum urate target and is flare-free 1
• Prophylactic therapy may be beneficial for at least the first 6 months of uric acid-lowering therapy 3
• An increase in gout flares commonly occurs after initiation of allopurinol due to mobilization of urate from tissue deposits 3, 4

Evidence Supporting This Approach

• In a placebo-controlled RCT of 43 patients starting allopurinol, colchicine 0.6 mg twice daily significantly reduced acute attacks (7/21 patients vs 17/22 in placebo group), with a number needed to treat of 2 1
• The FDA label specifically states that colchicine is recommended upon initiation of gout flare prophylaxis with uric acid-lowering therapy 3
• Maintenance doses of colchicine should generally be given prophylactically when allopurinol is begun 4

Dose Adjustments for Special Populations

Renal Impairment

• Reduce colchicine dose in patients with renal impairment 1
• This is critical as renal dysfunction increases the risk of colchicine toxicity 4

Drug Interactions

• Avoid colchicine entirely in patients receiving strong P-glycoprotein and/or CYP3A4 inhibitors (cyclosporine, clarithromycin) 1
• If strong CYP3A4 inhibitors cannot be avoided, significant dose reductions are required per FDA labeling 3

Common Pitfalls to Avoid

• Do not start allopurinol without concurrent anti-inflammatory prophylaxis, as this significantly increases the risk of acute gout flares during the mobilization phase 2, 3
• Do not use higher colchicine doses than recommended, as high doses lead to side effects while low doses (0.5 mg three times daily or less) may be sufficient 2
• Colchicine can cause diarrhea (relative risk 8.38 compared to placebo), so monitor for gastrointestinal side effects 1
• Monitor for neurotoxicity and muscular toxicity, especially in patients with renal impairment or concurrent statin use 1

Alternative Prophylaxis Options

• If colchicine is contraindicated or not tolerated, low-dose NSAIDs with gastro-protection can be considered 2, 1
• Low-dose prednisone/prednisolone is an alternative, particularly in CKD stage 3 1
• NSAIDs should be avoided in severe renal impairment 1

Coordination with Allopurinol Dosing

• Start allopurinol at 100 mg daily (or ≤50 mg daily in patients with CKD stage ≥3) and increase by 100 mg every 2-4 weeks 2
• This "start low, go slow" strategy for allopurinol, combined with colchicine prophylaxis, minimizes the risk of flares during urate-lowering therapy initiation 2, 4
• The combination of low-dose allopurinol initiation plus colchicine prophylaxis is more effective than either strategy alone 2