Balsalazide Mercaptopurine

Thiopurines are metabolized by thiopurine methyltransferase, whose activity is controlled by a common genetic polymorphism in the short arm of chromosome 6. Patients with low or intermediate activity who take azathioprine or 6-mercaptopurine are at risk of myelosup-pression caused by excess accumulation of the active thiopurine metabolite 6-thioguanine nucleotide. Benzoic acid derivatives, such as mesalazine and its precursors, and prodrugs (sulfasalazine, olsalazine, and balsalazide) inhibit thiopurine methyltransferase activity in vitro. This action could explain the increase in whole blood concentrations of 6-thioguanine nucleotide, leading to leukopenia. 

Traditional medical therapies for Crohn s disease include sulfasalazine and corticosteroids. These are pluripotent, reducing the production of inflammatory mediators and cytokines, although the complex and multiple mechanisms remain incompletely understood. Novel therapies related to newer aminosalicylate preparations such as balsalazide (colazide) or olsalazine (dipentum) newer corticosteroids such as budesonide immunomodulators such as azathioprine, 6-mercaptopurine, or methotrexate and antibiotics such as metronidazole are aimed at more specific delivery of active compounds to the site of disease, reduction of systemic absorption and side effects, and modulation of more focal targets within the immune response and the action of specific proinflammatory cytokines. 

The frequency of clinically important neutropenia did not increase significantly in 10 patients with Crohn s disease reeeiving azathioprine or mercaptopurine when they were given balsalazide 6.75 g daily for... 

Lowry PW, Szumlanski CL, Weinshilboum RM, Sandbom WJ. Balsalazide and azathioprine or 6-mercaptopurine evidence for a potentially serious drug interaction. Gastroenterology... 

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