Description
Mechanism of Action
Allopurinol is an inhibitor of the enzyme xanthine oxidase which converts hypoxanthine to xanthine then uric acid. The reduced production of uric acid relieves all symptoms associated with hyperuricaemia and gout. Inhibition of xanthine oxidase leads to accumulation of its substrates hypoxanthine and xanthine but since their renal clearance is more than 10 times that of uric acid, there is no risk of nephrolithiasis.
Absorption: 90% of the dose is absorbed from the GI tract (oral); peak plasma concentrations after 1-2 hrs.
Distribution: Enters breast milk. Protein-binding: None.
Metabolism: Converted to oxipurinol (alloxanthine).
Excretion: Urine (as unchanged drug and metabolite), faeces. Elimination half-life: 1-2 hr (allopurinol), 15 hr (oxipurinol).
MIMS Class
Hyperuricemia & Gout Preparations
ATC Classification
M04AA01 – allopurinol; Belongs to the class of preparations inhibiting uric acid production. Used in the treatment of gout.;
