Thiopurines for inflammatory bowel disease: Role of pharmacogenetics

There is a growing interest in the use of thiopurines for inflammatory bowel disease. Pharmacogenetic insights suggest that the genetic profile of thiopurine S-methyltransferase and inosine triphosphate pyrophosphatase may affect the clinical response to thiopurines. This is a review on the pharmacogenetics of these enzymes and highlights difficulties that impede prior-to-treat pharmacogenetic testing for the thiopurines in practice.