[Interference of noramidopyrin and its derivatives on the dosage of uric acid]

Administration of noramidopyrine or of noramidopyrine-methane-sulfonate interferes with the determination of blood uric acid by both the colorimetric method of Folin-Denis and an enzymatic uricase peroxidase method. This interference which is observed at least during the 24 hours following intravenous administration of noramidopyrine, results in either an increase (Folin-Denis) or a decrease (uricase) of the intensity of the final colour. The same effects are also observed in vitro when one adds noramidopyrine to an aqueous solution of uric acid. Existence of this interference should be taken into consideration especially in the diagnosis, the prognosis and the analgesic treatment of renal lithiasis.