Drug Interactions in Neonates and Infants

Abstract

When we talk about drug interactions in treatment of children up to 1 year old, we should remember that human milk is present in the alimentation of these patients. It is widely published that cow’s milk contains a high level of xanthine oxidase enzyme, which can interact with 6-mercaptopurine; this interaction is clinically significant. 6-Mercaptopurine is catabolized by xanthine oxidase to the inactive metabolite 6-thiouric acid. It is recommended in these publications to avoid cow’s milk with mercaptopurine. Although the enzyme may be isolated from human milk and is then obtained in quantities comparable to those from bovine milk, the activity of xanthine oxidase in human milk is low in comparison with that in cow’s milk. In comparison with its activity in bovine milk, xanthine oxidase in human milk has extremely low specific activity in all assays with reducing substrates other than reduced nicotinamide ad enine dinucleotide (NADH) [1, 92, 93].