From the Guidelines
Allopurinol dosing should be started at a low dose of 100 mg daily and gradually increased to reach the target serum uric acid level, typically below 6 mg/dL, as recommended by the 2016 updated EULAR evidence-based recommendations for the management of gout 1.
Key Considerations
- The starting dose of allopurinol should be no greater than 100 mg per day, and less than that in moderate to severe chronic kidney disease (CKD) 1.
- The maintenance dose can be raised above 300 mg daily, even in patients with CKD, as long as this is accompanied by adequate patient education and monitoring for drug toxicity 1.
- Prior to initiation, consider HLA-B*5801 in selected patients, specifically in higher risk sub-populations for severe allopurinol hypersensitivity reaction 1.
Dosing Adjustments
- Dose adjustments should be made every 2-4 weeks based on uric acid levels and tolerance 1.
- Patients with impaired kidney function require lower doses; for example, those with a creatinine clearance of 10-20 mL/min should receive 200 mg daily, while those with clearance below 10 mL/min should receive 100 mg daily 1.
Important Notes
- Allopurinol should be taken with food to minimize gastrointestinal upset, and adequate hydration is important during treatment.
- During the initial weeks of therapy, patients may experience increased gout flares, so prophylaxis with colchicine (0.6 mg once or twice daily) or a low-dose NSAID is recommended for the first 3-6 months of treatment 1.
From the FDA Drug Label
The dosage of allopurinol tablets to accomplish full control of gout and to lower serum uric acid to normal or near-normal levels varies with the severity of the disease. The average is 200 to 300 mg/day for patients with mild gout and 400 to 600 mg/day for those with moderately severe tophaceous gout The minimal effective dosage is 100 to 200 mg daily and the maximal recommended dosage is 800 mg daily To reduce the possibility of flare-up of acute gouty attacks, it is recommended that the patient start with a low dose of allopurinol tablets (100 mg daily) and increase at weekly intervals by 100 mg until a serum uric acid level of 6 mg/dL or less is attained but without exceeding the maximal recommended dosage.
The recommended allopurinol dosing is as follows:
- Mild gout: 200 to 300 mg/day
- Moderately severe tophaceous gout: 400 to 600 mg/day
- Initial dose: 100 mg daily, increased by 100 mg at weekly intervals until a serum uric acid level of 6 mg/dL or less is attained
- Maximal recommended dosage: 800 mg daily
- Minimal effective dosage: 100 to 200 mg daily 2
From the Research
Allopurinol Dosing
The provided studies do not directly address the optimal dosing of allopurinol. However, the following information can be gathered:
- Allopurinol is often prescribed at dosages of 100-300 mg/day 3
- In patients with chronic kidney disease (CKD), allopurinol may require dosage adjustment, whereas febuxostat does not 3, 4, 5, 6
- The efficacy of allopurinol in reducing serum uric acid levels is generally lower than that of febuxostat 3, 4, 6, 7
- Some studies suggest that febuxostat may be more effective and safer than allopurinol in patients with CKD and hyperuricemia 4, 5, 6
Key Considerations
When determining the optimal dosing of allopurinol, consider the following:
- Patient's renal function: Allopurinol may require dosage adjustment in patients with CKD 3, 4, 5, 6
- Serum uric acid levels: Allopurinol may not be as effective as febuxostat in reducing serum uric acid levels 3, 4, 6, 7
- Potential side effects: Allopurinol may have a higher risk of skin reactions and other adverse events compared to febuxostat 7
Dosage Comparison
Some studies provide the following dosage comparisons: