TY - JOUR T1 - Adverse effects of sulfasalazine in patients with rheumatoid arthritis are associated with diplotype configuration at the N-acetyltransferase 2 gene. JF - The Journal of Rheumatology JO - J Rheumatol SP - 2492 LP - 2499 VL - 29 IS - 12 AU - Eiichi Tanaka AU - Atsuo Taniguchi AU - Wako Urano AU - Hiroshi Nakajima AU - Yuko Matsuda AU - Yutaka Kitamura AU - Masayuki Saito AU - Hisashi Yamanaka AU - Terunobu Saito AU - Naoyuki Kamatani Y1 - 2002/12/01 UR - http://www.jrheum.org/content/29/12/2492.abstract N2 - OBJECTIVE: N-acetyltransferase 2 (NAT2) is a key enzyme for the acetylation of sulfasalazine (SSZ). We examine whether there was a correlation between diplotype configurations (combinations of 2 haplotypes for a subject) at the NAT2 gene and the adverse effects of SSZ used for the treatment of rheumatoid arthritis (RA). METHODS: The findings from 144 patients with RA who had been treated with SSZ were collected from our outpatient department and used for a retrospective study. Haplotype analysis was performed by the maximum-likelihood estimation based on the EM algorithm using the obtained polymorphism data. RESULTS: Sixteen patients (11.1%) had experienced adverse effects from SSZ, the most common being allergic reactions including rash and fever. The slow acetylators who had no NAT2*4 haplotype had experienced adverse effects more frequently (62.5%) than the fast acetylators who had at least one NAT2*4 haplotype (8.1%) (p < 0.001, OR 7.73, 95% CI 3.54-16.86). In 25% of the slow acetylators, the adverse effects were so severe that they were hospitalized. CONCLUSION: Genotyping the NAT2 gene followed by estimation of diplotype configuration before administration of SSZ is likely to reduce the frequency of adverse effects in Japanese patients with RA. ER -