Ankylosingspondylitis (AS) is a systemic inflammatory disease characterized by involvement of the spine and sacroiliac joints, which mostly presents clinically with inflammatory low back pain, stiffness and limitation of motion. Although the causative factors of AS are still not fully understood and there is still a lot of confusion in clinical diagnosis and treatment, new strategies for the treatment of AS have gained promising new experiences in recent years. The current status of AS treatment is reviewed as follows. Non-steroidal anti-inflammatory drugs are one of the main symptomatic drugs traditionally used in the treatment of AS, which can inhibit the inflammatory process and reduce joint pain, swelling and morning stiffness. The commonly used drugs include indomethacin and diclofenac. NSAIDs have been clinically proven to play an important role in the treatment and improvement of patients’ quality of life by relieving their clinical symptoms. COX 2 is an inducible enzyme, so selective COX 2 inhibitors not only have good anti-inflammatory and analgesic effects, but also have fewer adverse effects. COX 2 inhibitors may cause cardiovascular, renal and allergic adverse reactions, which should be taken into account in their application. Currently, the treatment of AS patients is mainly based on the use of NSAID drugs to relieve symptoms, but for patients who are difficult to control with NSAIDs, second-line drugs such as DMARD can be used to relieve and improve the disease. Sulfasalazine (SSZ) SSZ is the most studied drug in the DMARD class for AS. SSZ inhibits leukocyte motility, reduces proteolytic enzyme activity, and inhibits various cytokines such as interleukin (IL) 6, IL 1α, IL 1β, and tumor necrosis factor (TNF). There is no clear evidence of improvement in function, pain, or flexibility of spinal motion. The main adverse effects of these drugs are gastrointestinal and neurological, such as nausea, vomiting, and headache, as well as skin rash and bone marrow suppression. Therefore, while treating with SSZ, care should be taken to individualize the dose, as the adverse effects increase with the dose. Methotrexate (MTX) MTX is a folic acid antagonist with a high affinity for dihydrofolate reductase, which competitively binds to it and blocks the activity of the enzyme, preventing the conversion of folic acid into physiologically active tetrahydrofolate, preventing the conversion of deoxyuridine into deoxynucleotide, and blocking DNA synthesis. MTX also prevents the biosynthesis of purine nucleotides, thus interfering with the synthesis of RNA and protein. MTX has been found to be effective and safe in patients with AS, but the durability of its effects and the safety of its long-term use still need to be evaluated in long-term studies. Because MTX is a cytotoxic drug, common adverse effects include: nausea, dyspepsia, alopecia, bone marrow suppression, and serious adverse effects such as liver damage and lung lesions. Therefore, it is important to weigh the pros and cons, pay attention to the toxic side effects, and monitor liver function in the application. If the above drugs are not effective, other DMARD drugs such as Erofloxacin and Cyclosporine may be used as appropriate. Biological agents As the research on AS has intensified, new biological agents for the treatment of AS have been developed in recent years to alleviate and improve the disease, and the research on them has become the current hot spot. In recent years, anti-TNF α therapy has been tried for the treatment of AS at home and abroad, and has achieved good efficacy. Currently, the main biological agents used in clinical treatment of AS include soluble TNF α receptor fusion protein (Etanercept) and anti-TNF α monoclonal antibody (a fully humanized dimeric fusion protein, formed by fusing the extracellular segment of TNF α receptor p75 with human IgG1Fc segment, which binds with high affinity to TNF α, resulting in the loss of biological activity of TNF α. Etanercept has been approved for the treatment of rheumatoid arthritis, AS, polyarticular juvenile rheumatoid arthritis, and psoriatic arthritis. etanercept has also been extensively studied for the treatment of AS. In the study conducted by Gorman et al, 40 patients were treated with either 25 mg of Etanercept (25 mg twice/week) or placebo in two groups: (i) patients entering the study were continued on DMARD (40%) and hormones (25%); and (ii) different efficacy evaluation parameters were used. After 6 months of treatment, the main efficacy evaluation parameters such as morning stiffness and nocturnal spinal pain improved significantly in the treatment group, while there was no change in the placebo group. In a study of 20 patients with AS, In man et al. showed a significant improvement in signs and symptoms in adult patients with early AS after at least 24 weeks of Etaner cept. Maksymowych suggests that Etanercept may correct cartilage destruction to some extent and improve the clinical symptoms of AS, but larger and more in-depth studies are needed to verify this. The main adverse effects of Etanercept include infusion reactions, delayed metaplasia, increased chance of infection, exacerbation of heart failure, and a possible increase in the incidence of lupus-like syndrome and malignancies of the lymphatic system and bone marrow. Infliximab has been approved for the treatment of active rheumatoid arthritis, Crohn’s disease, psoriatic arthritis and AS. It is also effective in reactive arthritis, unclassified spondyloarthropathies, adult Still’s disease, and nodular disease. Open studies of Infliximab for AS or SpA have been conducted in Belgium, Canada, France, and Spain, and the response to treatment was similar in all patients up to 80%. Schatteman et al. investigated by intra-articular injection of NSAID, SSZ, and intra-articular hormone injections into the joint cavity in three patients who met the diagnostic criteria for AS New York and still had recurrent knee osteoarthritis in The results showed significant improvement in clinical and biological changes and MRI. The authors concluded that intra-articular infliximab is a safe and effective alternative to the non-intestinal route in patients with refractory monoarthritic AS, based on the efficacy of intra-articular infliximab in patients with uncontrollable arthritic manifestations of AS. Infliximab has a high cost effectiveness in the treatment of patients with active AS. Although the efficacy of Infliximab in the treatment of AS has been confirmed, the durability of its efficacy and the recurrence after discontinuation of the drug need to be further investigated and addressed. Since biologics are expensive, the indications should be strictly controlled, and the patient’s condition should be closely monitored and the drug should be selected according to the patient’s financial situation. Other treatments Thalidomide inhibits the production of TNF α and IL 12 by monocytes, and also synergistically stimulates human T lymphocytes and helper T cell response, and inhibits angiogenesis and adhesion molecule activity. Clinical observation shows that thalidomide can reduce the serum TNF α level of leprosy patients by 50% to 80%. Thalidomide is a promising drug for refractory AS, and its biological mechanism of action is related to the inhibition of TNF α gene expression. Thalidomide is a potential therapeutic agent for refractory AS, but its use is contraindicated in women who are pregnant or at risk of conception due to its effects on fetal development. Peripheral neuropathy may occur in some cases. Other adverse effects include morning sleepiness, dry mouth, and constipation. Pamidronate is a diphosphonate drug that has been shown to inhibit bone resorption. Recent studies have found that it inhibits the antigen-presenting effect of monocytes by inhibiting IL 1β production, macrophage growth, migration, differentiation and viability. Pamidronate inhibits the production of TNF α, IL 1β, IL 6 and other inflammatory cytokines by macrophage lines cultured in vitro. Akerkar also analyzed a number of studies on pamidronate in the treatment of AS and concluded that pamidronate is a promising treatment option for AS, especially in early-stage AS patients with short duration of disease. Its side effects are mainly mild arthralgia and myalgia, fever after intravenous injection.