Products
Febuxostat is commercially available in the form of film-coated tablets (Adenuric). It was approved in many countries in 2016. It was registered in the EU in 2008 and in the US in 2009 (US: Uloric).
Structure and properties
Febuxostat (C16H16N2O3S, Mr = 316.4 g/mol), unlike allopurinol, does not have a purine structure. It is a thiaziol carboxylic acid derivative and exists as a white crystalline powder that is practically insoluble in water.
Effects
Febuxostat (ATC M04AA03) is a potent and selective inhibitor of xanthine oxidase. This enzyme is significantly involved in the formation of uric acid from purines (adenosine, guanosine). Differences from allopurinol: Febuxostat is a more potent inhibitor of xanthine oxidase, binds differently to enyzm, has no purine structure, and is more selective. Febuxostat is not biotransformed to the active metabolite oxypurinol as is allopurinol.
Indications
For the treatment of chronic hyperuricemia in diseases that have already resulted in urate deposition.
Dosage
According to the drug label. Tablets are taken once daily, independent of meals.
Contraindications
- Hypersensitivity
Do not start treatment until the gout attack has completely resolved. Full precautions can be found in the drug information leaflet.
Interactions
Febuxostat is glucuronidated and metabolized by CYP isozymes. It is a weak CYP2D6 inhibitor. Interactions are possible with mercaptopurine, azathioprine, theophylline, inhibitors, and inhibitors of glucuronidation.
Adverse effects
The most common adverse effects include acute gouty attacks, hepatic dysfunction, diarrhea, nausea, headache, rash, and edema. Febuxostat may rarely cause severe hypersensitivity reactions such as Stevens-Johnson syndrome and anaphylaxis.