Oyavas, known generically as Leflunomide, is a medication primarily used in the management of rheumatoid arthritis and psoriatic arthritis. It functions as a disease-modifying antirheumatic drug (DMARD), aiming to decrease inflammation and slow the progression of the disease rather than just alleviating symptoms. Oyavas works by inhibiting the activity of an enzyme necessary for the proliferation of immune cells that are involved in the inflammatory process. By doing so, it helps to reduce joint damage and enhance physical function. Due to its potential side effects, including liver damage and an increased risk of infections, monitoring by healthcare professionals is essential during treatment. It is often prescribed when patients have not responded adequately to other DMARDs.