Abstract
Leflunomide is a new disease modifying anti rheumatic drug (DMARD) for the treatment of active rheumatoid arthritis. Its mechanism of action differs from other DMARDs in that it inhibits the de novo pyrimidine synthesis by inhibiting dihydroorotate dehydrogenase and therefore prevents the proliferation of activated lymphocytes. As it has been prescribed worldwide, there is a great deal of much concerns regarding its potential adverse effects. Because leflunomide has an active metabolite with a long elimination half-life of approximately 2 weeks, serious adverse reactions may occur even after the leflunomide treatment has been stopped. The profile of serious reactions includes liver dysfunction, hematological disorders, severe skin reactions and respiratory dysfunction. Respiratory dysfunctions with leflunomide therapy are very rare and its incidence is lower than that of methotrexate therapy. However, there are reports in Japan showing that 5 patients died of interstitial pneumonitis and another 11 patients developed serious lung complications associated with leflunomide. This suggests the possibility of fatal respiratory toxicity of leflunomide. There are no reports of interstitial pneumonitis associated with leflunomide in Korea. We report a case of a 62-year old woman who developed interstitial pneumonitis, which might have been induced by leflunomide during the treatment of rheumatoid arthritis.
Leflunomide는 최근에 개발된 항류마티스 약물로서 기존의 약물과 작용기전이 다르면서 효과가 우수하여 활동성 류마티스관절염에 널리 사용되고 있다. 알려진 부작용에는 간독성과 피부독성, 조혈기능부전, 위장관계 증상등이 있는데, 시판후 조사에서는 호흡기계 부작용도 드물지만 경한 정도에서 치명적인 경우까지 모두 보고 되었다. 세계 각 처에서의 시판후 조사에 의하면 호흡기계 부작용으로 사망한 경우가 있어서 심각한 폐독성의 가능성을 시사한다. 우리나라에서는 leflunomide로 인한 호흡기계 부작용에 대한 보고가 없었다. 저자들은 leflunomide에 의한 간질성 폐렴 1예를 경험하였기에 문헌고찰과 함께 보고하는 바이다.
