Examples: Allopurinol, Febuxostat
Indication:
Prevention of gout
Dosing:
-Once daily with food and drink lots of water
-Need to dose adjust in kidney disease
Mechanism of Action:
Inhibits xanthine oxidase which is an enzyme which produces uric acid
Place in Therapy:
Recent developments seem to favour allopurinol because of wider dosing adjustments and better safety profile
Adverse Effects:
-rash (more likely with HLA-B 5801 positive allele for allopurinol)
-upset stomach (take with food)
-can be nephrotoxic (drink more water and dose adjust)
-diarrhea
-phototoxicity
-increased liver function tests
**increased risk of cardiovascular events with febuxostat
Drug Interactions:
azathioprine, mercaptopurine, theophylline --> all of these are cleared via xanthine oxidase, so they can accumulate with toxicity if used with urate-lowering therapies.