Purinol - Allopurinol

Currently, allopurinol is the only drug approved for use in inhibiting uric acid synthesis. Both allopurinol and its major metabolite, oxy-purinol, are xanthine oxidase inhibitors and thus impair the conversion of hypoxanthine to xanthine and xanthine to uric acid. Allopurinol also lowers the intracellular concentration of PRPP. Because of the long half-life of its metabolite, allopurinol can be given once daily. An oral daily dose of 300 mg usually is sufficient. Occasionally, as much as 600 to 800 mg/day may be necessary. 

Uric acid, hypoxanthine, xanthine, allopurinol, oxi-purinol and allopurinol-1-riboside by a modification of the method of Webster et al. on a Chrompack RP-8 column. Urine samples were preseparated on anion-exchange columns. For the determination of oxipurinol-7-riboside a preextraction of ribosides on Bio-Rad Affi-Gel 601 was necessary. For the determination of adenine the mobile phase contained 20% of methanol and was adjusted to pH 5.5. ... 

Excretion of purine into the gut in the presence of allo-purinol has been demonstrated, but block of purine absorption by allopurinol has not been excluded. 

Figure 3. Effect of oleic acid (10%) on the allo-purinol (0.75 gs/kg) induction of XDH in chick liver. Chicks were fed Startena (18% protein) for three weeks before materials were added to this diet. Controls ( ), allopurinol (O), oleic acid (A ), and allopurinol plus oleic acid ( ). The allopurinol was removed prior to measuring XDH activities (6).

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