In addition to the application of glucocorticoids, the treatment of some connective tissues in rheumatic diseases also requires the rational use of various immunosuppressive agents. In recent years, cyclophosphamide (CTX) has received increasing attention due to its wide application, precise efficacy, and low cost economy. Cyclophosphamide is a synthetic alkylating agent, which needs to be metabolized by the liver to form highly active phosphoramidite mustard and acrolein, which are cross-linked with nucleic acid and damage
These substances cross-link with nucleic acids and kill immune cells by damaging DNA. In addition, it has been found to have immunosuppressive, immunomodulatory and anti-inflammatory effects by observing its effects on the lymphatic system. It is mainly used clinically for: (1) Systemic lupus erythematosus: It is generally used for the treatment of lupus nephritis and neuropsychiatric lupus, and it is mostly effective only when the total amount applied reaches 3-4 grams or more. The method of use includes high-dose shock therapy, i.e. 1 gram added to 200 ml of physiological saline, and once a month, static dose or small dose of 200-400 mg, applied once every 2-7 days, can be pushed or taken orally. The number of treatments can be reduced after the disease is in remission, and the course of treatment usually takes 2 to 3 years. (2) Systemic vasculitis: such as Wegener’s granulomatosis, polyarteritis nodosa, aortitis, etc. Due to the rapid progression of the disease and the involvement of many organs, hormones and CTX should be applied as early as possible. They are usually given in small doses of 200 mg every other day or 2 mg/
(kg? day), orally or by static push. In leukoaraiosis with central nervous system involvement, 1 gram of intravenous shock is required for 1 year of treatment. (3) Other connective tissue diseases: such as rheumatoid arthritis, polymyositis, dermatomyositis, scleroderma, dry syndrome, such as systemic vasculitis is more serious, the application of CTX is also effective. Most are given orally at 1-2 mg per kg body weight per day. Theoretically, the longer the application time and the higher the dose of CTX, the easier the disease can be controlled and the longer the remission time, but the toxic side effects are also more obvious.