Leflunomide is a medication used to treat rheumatoid arthritis. There are several synonyms for this drug, including leflunomide sodium, Arava, and HWA 486. Leflunomide sodium is a salt form of leflunomide that is used to make the medication easier to dissolve in water. Arava is the brand name for leflunomide and is commonly used in the United States. The term HWA 486 is an older name for leflunomide that was used during its development phase. Regardless of which name is used, leflunomide remains an effective medication for reducing inflammation and joint pain associated with rheumatoid arthritis. Patients should always follow their doctor's instructions when taking this medication.