Azathioprine is recommended as the first-line steroid-sparing immunosuppressive agent for myasthenia gravis. Mycophenolate and methotrexate are often considered as second-line choices despite widespread consensus on their efficacy. We aimed to gather real-world data comparing the tolerability and reasons for discontinuation for these agents, by performing a national United Kingdom survey of side effects and reasons for discontinuation of immunosuppressants in myasthenia gravis. Of 235 patients, 166 had taken azathioprine, 102 mycophenolate, and 40 methotrexate. The most common side effects for each agent were liver dysfunction for azathioprine (23 %), diarrhoea for mycophenolate (14 %), and fatigue for methotrexate (18 %). Women were generally more likely to experience side effects of immunosuppressants. Azathioprine was significantly more likely to be discontinued than mycophenolate and methotrexate due to side effects. There was no significant difference in treatment cessation due to lack of efficacy. This study highlights the significant side-effect burden of treatment for myasthenia gravis. Mechanisms to reduce azathioprine toxicity should be utilised, however mycophenolate and methotrexate appear to be good treatment choices if teratogenicity is not a concern. Women are disadvantaged due to higher frequency of side effects and considerations around pregnancy and breastfeeding. Treatments with improved tolerability are needed.

中文翻译：

---

麦考酚酯和甲氨蝶呤在治疗重症肌无力方面比硫唑嘌呤具有更好的耐受性

硫唑嘌呤被推荐作为治疗重症肌无力的一线类固醇免疫抑制剂。尽管麦考酚酯和甲氨蝶呤的功效已得到广泛共识，但它们通常被视为二线选择。我们的目的是通过对重症肌无力免疫抑制剂的副作用和停用原因进行英国全国调查，收集真实世界数据，比较这些药物的耐受性和停用原因。 235 名患者中，166 名服用了硫唑嘌呤、102 名霉酚酸酯和 40 名甲氨蝶呤。每种药物最常见的副作用是硫唑嘌呤的肝功能障碍 (23%)、麦考酚酯的腹泻 (14%) 和甲氨蝶呤的疲劳 (18%)。女性通常更容易出现免疫抑制剂的副作用。由于副作用，硫唑嘌呤比麦考酚酯和甲氨蝶呤更有可能被停用。由于缺乏疗效而停止治疗的情况没有显着差异。这项研究强调了重症肌无力治疗的显着副作用负担。应利用减少硫唑嘌呤毒性的机制，但如果不担心致畸性，麦考酚酯和甲氨蝶呤似乎是不错的治疗选择。由于副作用发生频率较高以及怀孕和母乳喂养方面的考虑，女性处于不利地位。需要提高耐受性的治疗。