**6.21. Leflunomide**

Leflunomide is used for maintenance immunousppression especially in patients with BK nephropathy. [50, 51] It has both imunosuppressive properties and antiviral activity against BK. It blocks pyramidine synthesis in lymphocytes. The common adverse effects with its use are GI toxicity and neuropathy. There are no major drug interactions with leflunomide.
