Among the wide variety of anti-rheumatic drugs, there is a drug called “Leflunomide”. It is often used in the treatment of rheumatoid diseases such as rheumatoid arthritis and systemic lupus erythematosus. What is the pathway of Leflunomide to fight rheumatism and what are its side effects? Let me answer your questions now. Rheumatic immune diseases occur because the body’s immune system is abnormally activated by certain factors, the body produces a large number of immune cells, and immune reactions occur in multiple tissues throughout the body, causing inflammatory damage to the body. Leflunomide is a drug that can inhibit the abnormal proliferation of immune cells. It inhibits a substance called “dihydroorotic acid dehydrogenase”, which is necessary for the synthesis of “pyrimidine”. Pyrimidines are necessary for the growth of immune cells. Leflunomide can reduce the immune cells and immune response by blocking the synthesis of immune cells. In addition, leflunomide can also act on key pathways in the immune inflammatory response, such as inhibiting the activation process of “tyrosine kinase” and “NF-κB”, thus reducing the inflammatory response. In clinical trials, leflunomide has been shown to significantly reduce clinical symptoms in patients with rheumatoid arthritis, systemic lupus erythematosus and other rheumatic immune diseases, effectively reducing inflammatory indexes and reducing inflammatory damage to joints, kidneys and other organs. Leflunomide has also gradually started to be used in the treatment of other rheumatic immune diseases. Leflunomide is easy to use, usually only one or two capsules are needed daily, and the price is moderate, about one hundred dollars a month. It is usually used in combination with other anti-inflammatory and immunosuppressive drugs to enhance the efficacy of anti-rheumatic treatment. The use of Leflunomide is generally safer, and it is less gonadal suppressive than traditional anti-rheumatic drugs such as Reglan. During the treatment period, we need to pay attention to the change of blood pressure, because some patients will have elevated blood pressure during the drug. For patients with pre-existing hypertension, it is even more important to monitor blood pressure several times and increase the dosage of blood pressure medication in a timely manner. In addition, during the medication period, we need to follow up with the clinic and take blood tests according to the doctor’s instructions, mainly liver function and blood tests. If elevated transaminases and reduced white blood cells are found, there is no need to worry too much, as they can generally be restored to normal after the doctor adjusts the medication. Other possible side effects are hair loss and nausea, which are generally mild and do not affect the continued use of the drug. In addition, Leflunomide is a kind of immunosuppressant and the body’s resistance will be reduced during the use period, so pay more attention not to stay up late or get cold to prevent the occurrence of infection. Leflunomide has been used for many years in rheumatologic diseases and has been proven to be effective and safe in a large number of clinical trials, and with its affordable price, it is widely used in the treatment of rheumatoid arthritis and systemic lupus erythematosus. Although the drug still has many possible side effects, it can certainly be used under the guidance of an experienced rheumatologist specialist to cure the disease safely and without toxicity.