GPT and toxic epidermal necrolysis: Moreover, the NAT2 SA phenotype is associated with the pharmacokinetics of a different sulfur drug, sulfamethoxazole, in renal transplant recipients (Kagaya et al., 2012) and with adverse reactions to sulfamethoxazole, such as toxic epidermal necrolysis, Stevens-Johnson syndrome, and increased serum alanine aminotransferase levels in patients with systemic lupus erythematosus (Soejima et al., 2007).