| Although thioguanine has several times the potency of mercaptopurine in experimental animals, it is only slightly more potent in man. |
| Thioguanine is a close relative of mercaptopurine and like the latter is an antimetabolite which blocks purine metabolism. |
| Preponderance of thiopurine Smethyltransferase deficiency and heterozygosity among patients intolerant to mercaptopurine or azathioprine. |
| However, febuxostat is contraindicated in patients who are taking azathioprine, mercaptopurine, and theophylline. |
| Moreover, trans effects of single-nucleotide polymorphisms that affect TPMT activity and mercaptopurine sensitivity have recently been discovered in the PACSIN2 gene. |
| This methylation occurs only to a minor degree in other species studied. This accounts for the difference in ratio of activity of mercaptopurine and thioguanine in different species. |
