• Azaribine is an effective agent in the treatment of psoriasis. In this investigation the extent of clinical dermatologic remission appeared to correlate with the degree of metabolic block induced by 6-azauridylic acid, as quantitated by the urinary excretion of orotic acid and orotidine, and the development of anemia.
Following azaribine therapy there was a coordinate rise of the specific activities of erythrocyte orotate phosphoribosyltransferase and orotidine-5′-monophosphate decarboxylase. There was no correlation between the pretreatment activity of these enzymes and the clinical response to azaribine.
The anemia of azaribine therapy was mild and of a megaloblastic type. Uridine effectively corrected the azaribine-induced anemia, but led to exacerbation of the patients' psoriasis. Following uridine therapy there was a reduction in the urinary excretion of orotic acid and orotidine, presumably reflecting end-product inhibition or repression of the first steps of a repeated pyrimidine biosynthesis.
(Arch Dermatol 112:1717-1723, 1976)