From the Guidelines
The smallest available dose of febuxostat is 40 mg once daily, which is also the recommended starting dose for most patients with gout. This medication works by inhibiting xanthine oxidase, the enzyme responsible for converting xanthine to uric acid, thereby reducing serum uric acid levels 1. For patients with mild to moderate renal impairment, no dose adjustment is necessary, but caution should be exercised in severe renal impairment. Elderly patients can also typically start with the 40 mg dose. If serum uric acid levels remain above 6 mg/dL after 2-4 weeks of treatment, the dose can be increased to 80 mg once daily. Patients should take febuxostat with or without food at approximately the same time each day. During initiation of therapy, patients may experience an increase in gout flares due to mobilization of urate crystals, so prophylaxis with colchicine or an NSAID is often recommended for the first few months of treatment. Liver function should be monitored periodically as febuxostat has been associated with elevated liver enzymes in some patients.
Some key points to consider when prescribing febuxostat include:
- Starting with a low dose and titrating as needed to minimize the risk of adverse effects 1
- Monitoring serum uric acid levels regularly to assess the effectiveness of treatment
- Being aware of the potential for increased gout flares during the initial treatment period and taking steps to mitigate this risk
- Considering the use of alternative therapies, such as allopurinol or pegloticase, in patients who do not respond to febuxostat or who experience adverse effects.
It's also important to note that febuxostat has been found to be more effective in patients with chronic kidney disease (CKD) than allopurinol given at doses adjusted to creatinine clearance, and can be used in these patients 1. However, the dose recommendations in renal disease may slightly differ across countries, and it's recommended to follow the local Summary of Product Characteristics.
From the Research
Smallest Dose of Febuxostat
- The smallest dose of febuxostat is not explicitly stated in all studies, but according to 2, the recommended starting dosage is 40 mg orally once daily.
- However, a study 3 found that 83.0% of patients could remain with serum uric acid (sUA) < 360 µmol/L at a maintenance dose of febuxostat 20 mg/day.
- Another study 4 reported a mean dose of febuxostat of 15.9 (± 8) mg/day, which effectively reduced serum uric acid concentrations in patients with chronic kidney disease.
- It is essential to note that the dosage of febuxostat may vary depending on the patient's condition, renal function, and other factors, as stated in 2, which recommends increasing the dosage to 80 mg orally once daily if serum uric acid concentrations are not less than 6 mg/dL after two weeks.
Dosage Adjustments
- According to 2, dosage adjustments are not needed in elderly patients or patients with mild or moderate renal or hepatic impairment.
- However, patients with chronic kidney disease may require closer monitoring and adjustment of the febuxostat dose, as reported in 3, 5, and 4.
- The studies suggest that febuxostat can be effective in reducing serum uric acid levels and slowing the progression of renal disease in patients with chronic kidney disease, but the optimal dose and dosage adjustments need to be determined on a case-by-case basis, as mentioned in 5 and 4.