Treat Ankylosing Spondylitis with Methazolamide

Background: Increased bone resorption and new bone information are two characteristics of ankylosing spondylitis (AS). Much evidence has shown that carbonic anhydrase inhibitors can restrain bone resorption. We had detected increased expression of carbonic anhydrase I (CA1) in synovium of patients with AS. This study aimed to evaluate the effectiveness and safety of methazolamide, an anti-carbonic anhydrase drug, for treating patients with AS. Methods: Two patients, called as S and L, were diagnosed with active AS based on BASDAI and BASFI assessments, radiographic data and other clinical indices. They took methazolamide tablets at a dose of 25 mg twice every day. Results: Patient S's BASDAI score fell from 5.4 to 4.4, while patient L's BASDAI fell from 2.4 to 2. Patient S's BASFI score change from 2.7 to 2.9, while patient L's BASFI score fell from 1.2 to 0.2. The ESR values of patient S were considerably reduced, while the ESR value of patient L remained unchanged and in the normal range. The calcium concentration of patient S decreased from 3.05 mmol/L to 2.39 mmol/L. The CT evidence indicates that the articular surfaces of the erosive sacroiliac joints became clearer and the area of the calcium deposits began decreased. No significant systemic side effects were observed in either patient. Conclusions: The above results indicate that methazolamide was effective for active AS. Methazolamide may improve AS symptoms by inhibiting carbonic anhydrase activity during the processes of bone reporption and new bone formation.