Title: Leflunomide—Clinical Application and Precautions of Immunomodulatory Drugs

First paragraph: content overview

Leflunomide is an immunomodulator mainly used to treat autoimmune diseases such as rheumatoid arthritis and psoriatic arthritis. Its core function is to regulate overactive immune responses by inhibiting pyrimidine synthesis. This article will focus on five aspects: drug mechanism, indications, medication precautions, common side effects and manufacturers, focusing on analyzing its clinical value and safety to help patients and doctors use it rationally.

Paragraph 2: Mechanism of action and indications

Leflunomide inhibits dihydroorotate dehydrogenase (DHODH) and blocks the synthesis of pyrimidines in lymphocytes, thereby reducing abnormal proliferation of immune cells. Clinical studies show that it can improve joint swelling and pain in moderate to severe rheumatoid arthritis by more than 60% (data source:Chinese Journal of Rheumatology). Indications also include adjuvant treatment of lupus nephritis, but it must be used strictly in compliance with the doctor's instructions.

Paragraph 3: Medication specifications and contraindications

The recommended initial dose for adults is 20 mg daily, which can be reduced to 10 mg during the maintenance period. Liver function needs to be monitored regularly during medication, as transaminases may increase. It is prohibited for pregnant women, lactating women and patients with severe liver disease. Peking Union Medical College HospitalProfessor Zhang FengchunPointed out: "When combined with methotrexate, you need to be alert to the risk of bone marrow suppression, and it is recommended to review blood routine every 3 months."

Paragraph 4: Common adverse reactions

About 15% of patients may experience diarrhea, hair loss or rash, and most symptoms are mild. The incidence of serious adverse reactions such as interstitial pneumonitis is less than 1% (data source:FDA drug insert). You should avoid taking live vaccines and pay attention to sun protection while taking the medicine. If you have persistent fever or difficulty breathing, seek medical attention immediately.

Paragraph 5: Summary and product information

Leflunomide is a basic drug for chronic immune diseases and needs to be used in a long-term and standardized manner. Major domestic manufacturers include Suzhou Changzheng-Xinkai Pharmaceutical (trade nameAi Ruohua), Fujian Huitian Biopharmaceuticals, etc. Patients should take medication under the guidance of a rheumatologist to balance efficacy and safety, and do not adjust the dosage on their own.

Quote sources:
1. Chinese Journal of Rheumatology "Multi-center Study of Leflunomide in the Treatment of Rheumatoid Arthritis"
2. FDA drug package insert (NDA 020905)
3. Professor Zhang Fengchun's "Rheumatology Clinical Medication Guide" (People's Medical Publishing House)