Drug Detail:Colchicine and probenecid (Colchicine and probenecid [ kol-chi-seen-and-pro-ben-e-sid ])
Drug Class: Antigout agents
Usual Adult Dose for Gouty Arthritis
Initial: 1 tablet orally once a day for 1 week
Maintenance: 1 tablet orally twice a day
- If symptoms of gouty arthritis are not controlled or 24-hour uric acid excretion is not above 700 mg, may increase dose in 1 tablet increments every 4 weeks as tolerated
Comments:
- One tablet contains probenecid 500 mg-colchicine 0.5 mg.
- Therapy should not be started until an acute gouty attack has subsided; if an acute attack is precipitated during therapy, this drug may be continued without changing the dose; additional colchicine or other appropriate therapy should be given to control the acute attack.
- To prevent crystallization of uric acid in urine, a liberal fluid intake (2 L/day) and alkalization of the urine should be encouraged; alkalization of urine may be relaxed when serum urate levels return to normal limits and tophaceous deposits disappear.
- The maintenance dose may be decreased in increments of 1 tablet every 6 months when acute attacks have been absent for 6 months or more and serum urate levels remain within normal limits; maintenance dosage should not be reduced to the point serum urate levels start to rise.
Use: For the treatment of chronic gouty arthritis complicated by frequent, recurrent acute attacks of gout.
Renal Dose Adjustments
Patients with renal impairment should not take colchicine in conjunction with drugs that inhibit both P-glycoprotein (P-gp) and CYP450 3A4.
CrCl less than 30 mL/min: Not recommended as it may not be effective
Mild to moderate renal impairment: Use caution; dosage requirements may be increased; monitor closely for colchicine toxicity.
Liver Dose Adjustments
Patients with hepatic impairment should not take colchicine in conjunction with drugs that inhibit both P-glycoprotein (P-gp) and CYP450 3A4.
Use caution; the possibility of increased colchicine toxicity in the presence of hepatic dysfunction should be considered.
Dose Adjustments
Gastric intolerance may be indicative of overdosage and may be corrected by decreasing the dose.
Urine alkalization:
- A liberal fluid intake (2 L/day) and alkalization of the urine is recommended when excretion of uric acid is at a high level; alkalization may be relaxed when serum urate levels return to normal and tophaceous deposits disappear.
- Sodium bicarbonate 3 to 7.5 g/day or potassium citrate 7.5 g/day may be used to maintain an alkaline urine.
- Acid-base balance should be watched carefully when alkali is administered.
Precautions
Safety and efficacy have not been established in patients younger than 18 years.
Consult WARNINGS section for additional precautions.
Dialysis
No data available; colchicine is not effectively removed by dialysis.
Other Comments
Administration advice:
- Take orally, with or without food
- Maintain adequate hydration (at least 2 L/day) and alkalization of the urine with sodium bicarbonate or potassium citrate as needed.
Storage requirements:
- Protect from light
General:
- Gastric intolerance may be indicative of toxicity and can be corrected by decreasing dosage.
- Therapy should not be started until an acute gouty attack has subsided; if an acute attack is precipitated during therapy, this drug may be continued without changing the dose; additional colchicine or other appropriate therapy should be given to control the acute attack.
- This drug is not an analgesic medication and should not be used to treat pain from other causes.
- Colchicine has a narrow therapeutic window; patients should be monitored closely for toxicity.
Monitoring:
- Monitor serum urate levels as needed to determine adequacy of treatment
- Monitor acid-base balance in patients administered alkali
- Monitor for toxicity, especially in geriatric and debilitated patients, patients with renal or hepatic impairment, and those with cardiac, renal, hepatic, or gastrointestinal disease.
- Monitor for hematologic toxicities; for patients developing signs or symptoms of blood cell dyscrasias, a full hematologic investigation should be conducted.
- Monitor renal function in patients at-risk for renal impairment
Patient advice:
- Instruct patients on the need for adequate hydration, alkalization of the urine, and/or dietary restrictions appropriate to their care.
- Inform patients that fatal overdose, both accidental and intentional, have occurred with colchicine; this drug should be kept out of the reach of children.
- Inform patients that there are a number of potentially serious drug interactions; grapefruit, grapefruit juice, salicylates, and some herbal products should be avoided; patients should check with their healthcare provider before starting any new medications including short-term medications such as antibiotics.
- Inform patients that bone marrow depression and neuromuscular toxicity may occur; patients should seek medical attention promptly for unusual bleeding or bruising, increased infections, weakness or fatigue, muscle pain or weakness, or numbness or tingling in fingers or toes.
- Inform patients that gastrointestinal adverse events occur, but if these events are severe or persistent, they should be reported promptly to their healthcare provider.