If a patient with rheumatoid arthritis has only osteoporosis and no narrowing of the joint space, it is called early rheumatoid arthritis. If the patient has developed narrowing of the joint space, it is called mid-stage rheumatoid arthritis. If the patient has fusion of the joints and significant ankylosis and deformity, the patient is considered to have advanced rheumatoid arthritis. For patients with rheumatoid arthritis, in order to avoid the development of advanced disease, it is important to add medications that can effectively relieve the progression of the patient’s joints as soon as the diagnosis is made. These drugs are called slow-acting drugs, and the most commonly used ones are methotrexate and leflunomide. During the use of these drugs, regular monitoring of blood, liver and kidney function is required to monitor the side effects of the drugs.