Possible Interaction: Allopurinol and Orotic Acid

“The administration of allopurinol leads to an increase of urinary excretion of orotic acid and orotidine (Fox et al. 197o) due to an inhibition of orotidine-5-phosphate decarboxylase (ODC).”

“Treatment with allopurinol leads to increased excretion of the pyrimidine compounds orotic acid and orotidine, and to increased levels in erythrocytes of the enzymes orotate phosphoribosyltransferase and orotidylate decarboxylase.”

“Evidence for this is provided by the observation that allopurinol leads to a striking increase in the urinary excretion of orotic acid and ~rotidine.'~." More direct evidence for these apparent inhibitory effects of allopurinol on purine and pyrimidine synthesis de now has been difficult to obtain in vim.”

“In addition to its well-established inhibitory effect on uric acid synthesis, allopurinol appears to alter substantially pyrimidine metabolism, as evidenced by a striking increase in the urinary excretion of orotidine and orotic acid.”

“Agents such as adenine and allopurinol , which inhibit the metabolism of orotic acid and thereby decrease the formation of uridine nucleotides, and galactosamine, which traps uridine nucleotides, inhibited the promotional effects of orotic acid in the liver.”

“ Allopurinol also had an effect on pyrimidine excretion in the pig as indicated by increased urinary orotic acid and orotidine levels, an effect not eliminated when guanine was given together with allopurinol. (”

“Abstract The administration of allopurinol to rats was found to interfere with de novo pyrimidine biosynthesis, resulting in increased urinary excretion of orotic acid and orotidine and elevated activities of the enzymes orotate phosphoribosyltransferase and orotidine-5′-phosphate decarboxylase in erythrocytes.”