What Febuxostat Does and How It Works
Febuxostat is a pill that lowers uric acid levels in your blood by blocking an enzyme called xanthine oxidase, which your body uses to make uric acid. 1, 2
What It Does
- Lowers uric acid levels in people with gout to prevent painful attacks and dissolve uric acid crystals that have built up in your joints 1, 3
- Prevents gout flares over the long term (after the first few months of treatment) by keeping uric acid levels low 4
- Shrinks tophi (lumps of uric acid crystals under the skin) when used long-term 5
How It Works
- Febuxostat blocks xanthine oxidase, an enzyme your body needs to produce uric acid 2, 3
- Unlike the older drug allopurinol, febuxostat is not related to purines (the building blocks that become uric acid), which makes it work differently in your body 2, 5
- By blocking this enzyme, less uric acid gets made, so levels in your blood drop below the point where crystals form (usually targeting below 6 mg/dL) 1, 4
Typical Dosage
- Start with 40 mg once daily by mouth 1, 2
- After 2 weeks, if your uric acid level is still above 6 mg/dL, increase to 80 mg once daily 1, 2
- The goal is to get your uric acid below 6 mg/dL (and sometimes below 5 mg/dL if you have severe gout with tophi) 1, 6
- No dose adjustment needed if you have kidney problems, unlike allopurinol 1, 5
Important Warnings
- Gout flares may increase during the first few months of starting febuxostat, so your doctor should prescribe colchicine or another medicine to prevent flares when you start 1, 4
- Cardiovascular concerns: If you have heart disease or have had a heart attack or stroke, febuxostat may increase your risk of cardiovascular death compared to allopurinol, so discuss this carefully with your doctor 7, 6
- Common side effects include stomach pain, diarrhea, liver test abnormalities, and rash 7