The influence of dietary purines and pyrimidines on purine and pyrimidine biosynthesis in man.

Allopurinol-induced orotaciduria is reduced by dietary ribonucleic acid (RNA), RNA hydrolysate and different nucleotides. These findings are compatible with feedback regulation of pyrimidine biosynthesis by dietary nucleotides. Serum uric acid and urinary uric acid excretion on a purine-free isoenergetic diet reach a minimum after about 10 days and remain constant thereafter. When purines from different biochemical sources are added to such a diet there is always a linear relationship between dietary purines and serum uric acid level and urinary uric acid excretion. The findings suggest that dietary purines play a minor role if any in the regulation of purine biosynthesis in man.

Disease-specific noncompliance with drug treatment as a cause of persistent hyperuricemia and gout in anorexia nervosa.

A 49 year old female patient with anorexia nervosa was admitted to the hospital because of treatment-refractory hyperuricemia and gout. Medical history and clinical findings were compatible with primary gout and uric acid nephropathy. The patient stated that she regularly took allopurinol. In the hospital she initially received 300 mg allopurinol daily after breakfast. In order to ensure allopurinol ingestion and absorption the plasma concentrations of both allopurinol and its active metabolite oxipurinol were determined in addition to serum uric acid and further clinical chemistry data. Despite allopurinol treatment no decrease of serum uric acid was observed for three days. Therefore the head nurse was instructed to supervise the intake of allopurinol carefully. During the following days serum uric acid decreased and plasma oxipurinol concentrations rose. On day 9 of treatment serum uric acid fell into the upper normal range. Therefore the patient was allowed to leave the hospital within a few days. However serum uric acid thereafter increased again while plasma oxipurinol declined. Later on it became evident that the patient had vomited self-induced approximately 15 minutes after allopurinol intake. In the meantime her husband had urged her to return home. Starting with day 18 benzbromarone treatment was added. Combined therapy with 400 mg allopurinol and 50 mg benzbromarone daily finally resulted in a serum uric acid concentration of 4.5 mg/dl at discharge from the hospital. About three weeks later the private physician again diagnosed hyperuricemia with serum uric acid values between 10 and 12 mg/dl. Meanwhile the patient needs to be dialysed due to end stage renal disease. Our observations show that self-induced vomiting to prevent effective treatment may be a disease-specific pattern of noncompliance with drug therapy in anorexia nervosa.