What is the recommended dosage of colchicine (Colcrys) for treating acute gout and for prophylaxis, especially in patients with Impaired renal function?

Colchicine Dosage for Acute Gout and Prophylaxis

For acute gout attacks, colchicine should be administered as a loading dose of 1.2 mg followed by 0.6 mg one hour later, with subsequent prophylactic dosing of 0.6 mg once or twice daily until the attack resolves; patients with severe renal impairment require dose reduction to a single dose of 0.6 mg with no repeat treatment for at least two weeks. 1

Acute Gout Treatment

Standard Dosing

• Colchicine should only be used for gout attacks with onset within the previous 36 hours 1
• The FDA-approved regimen is 1.2 mg at first sign of flare, followed by 0.6 mg one hour later 1, 2
• After the initial doses, continue with prophylactic dosing of 0.6 mg once or twice daily (12 hours after the initial doses) until the gout attack resolves 1

Renal Impairment Adjustments

• For mild (CrCl 50-80 mL/min) to moderate (CrCl 30-50 mL/min) renal impairment: No dose adjustment required, but monitor closely for adverse effects 3
• For severe renal impairment (CrCl <30 mL/min): No dose adjustment needed for acute treatment, but treatment course should not be repeated more than once every two weeks 3
• For patients on dialysis: Reduce to a single dose of 0.6 mg, with no repeat treatment for at least two weeks 3
• Treatment of gout flares is not recommended in patients with renal impairment who are already receiving colchicine for prophylaxis 3

Prophylaxis Dosing

Standard Prophylactic Dosing

• For gout flare prophylaxis: 0.6 mg once or twice daily 1
• Prophylaxis should be initiated with or just prior to starting urate-lowering therapy 1

Duration of Prophylaxis

• Continue for at least 6 months, OR
• 3 months after achieving target serum urate (if no tophi detected on physical exam), OR
• 6 months after achieving target serum urate (if tophi are present) 1

Renal Impairment Adjustments for Prophylaxis

• Mild to moderate renal impairment: No dose adjustment required, but monitor closely 3
• Severe renal impairment: Starting dose should be 0.3 mg/day with close monitoring 3
• Patients on dialysis: Starting dose should be 0.3 mg twice weekly with close monitoring 3

Drug Interactions and Special Considerations

Drug Interactions

• Dose reduction is required with concomitant use of moderate to high potency inhibitors of CYP3A4 and P-glycoprotein 1, 4
• Major interactions include clarithromycin, erythromycin, cyclosporine, and disulfiram 1
• Patients with renal or hepatic impairment should not be given colchicine with these interacting medications 3

Hepatic Impairment

• Mild to moderate hepatic impairment: No dose adjustment required for acute treatment, but monitor closely 3
• Severe hepatic impairment: No dose adjustment needed for acute treatment, but do not repeat treatment more than once every two weeks 3

Common Pitfalls and Caveats

• Colchicine has a narrow therapeutic index with no clear distinction between therapeutic, toxic, and lethal doses 4
• Delaying treatment beyond 36 hours after symptom onset significantly reduces effectiveness 1, 5
• Unintentional toxicity is common and often associated with poor outcomes, especially in patients with renal impairment 6, 4
• The lowest reported lethal doses of oral colchicine are 7-26 mg 4
• Colchicine should not be used in high doses for acute gout due to potential toxicity; the low-dose regimen (1.8 mg total over 1 hour) is as effective as higher doses with significantly fewer side effects 5, 2
• Gastrointestinal side effects (diarrhea, nausea, vomiting, cramps) are the most common adverse reactions 1, 4

By following these evidence-based dosing guidelines and carefully considering patient-specific factors such as renal function and potential drug interactions, colchicine can be used effectively and safely for both acute gout treatment and prophylaxis.