Physicians contemplating the use of azaribine (Triazure) should become familiar with the chemistry, pharmacologic aspects, and toxic effects of the drug. Therefore, we strongly recommend that these guidelines be carefully studied before the drug is administered.DESCRIPTION GeneralAzaribine (2′, 3′, 5′-triacetyl-6-azauridine) is the orally absorbable triacetylated derivative of the pyrimidine analog 6-azauridine. It is a white, odorless, crystalline substance that is very insoluble in water. The structural formula of azaribine is presented in the Figure.Azaribine is supplied as white film-coated tablets, each containing 500 mg of azaribine (active ingredient) and the following excipients: starch (USP), calcium sulfate, gelatin, magnesium stearate (USP), and distilled water.Biochemical ActivityThe primary action of this compound is related to the activity of the nucleoside 6-azauridine, which is a structural analog of uridine. In mammalian systems, 6-azauridine, after its metabolic conversion to 6-azauridine-5′-phosphate, competitively inhibits intracellular pyrimidine nucleotide synthesis. The primary