MUSCLE RELAXANTS: ARE THEY NEEDED IN ANKYLOSING SPONDYLITIS?

Abstract

Guidelines for the treatment of ankylosing spondylitis (AS) lack muscle relaxants. At the same time, the latter are used for combined therapy using nonsteroidal anti-inflammatory drugs (NSAIDs) in 53.1% of patients in an outpatient setting. No clear recommendations make the administration of these agents uncontrolled, on the one hand, and substantially restrict therapeutic possibilities, on the other. Objective: to investigate the short-term effect and safety of using tolperisone hydrochloride (THC, Mydocalm®) in patients with AS during group therapeutic exercise (TE). Subjects and methods. The investigation included 40 patients aged over 18 years with a valid diagnosis of AS who had been treated at the Clinic of the V.A. Nasonova Research Institute of Rheumatology and agreed to participate in the study. All the patients were randomized in a 1:1 ratio into two groups: 1) 20 patients used NSAIDs in combination with TE; 2) 20 patients received NSAIDs, TE, and THC 450 mg/day. The groups were matched for age, gender, disease duration, and functional impairments. Before and after completion of the investigation, the investigators estimated BASDAI, BASFI, patient-rated numerical pain rating scale (NPRS), patient-rated TE performance scores (NPRS, where 0 (very effective), 10 (ineffective), THC tolerance monitoring (consideration of adverse events). Spinal motility was evaluated using BASMI and chest excursion measurement. Results and discussion. During TE, both groups showed a significant increase in the volume of movements (p < 0.03), when measuring chest excursion and carrying out modified Schober's test, a decrease in BASDAI (p < 0.01) and BASFI (p < 0.009), as well as a reduction in patient-rated overall disease activity assessment (p < 0.02) as compared to the baseline values. At the same time the modified Schober test revealed that the increase in motility was significantly higher in Group 2 than in Group 1 (p < 0.05). During the follow-up, the patient-rated evaluation of TE efficiency remained significantly unchanged in Group 1 whereas at the end of the study it significantly increased in Group 2 as compared to the baseline values (p < 0.01). There were no significant differences between the groups in the time course of changes in BASDAI and BASFI. When performing the BASMI tests, there was an intensive increment in the volume of movements after the third TE lesson. The increment occurred saltatorily in Group 1, but more rapidly and evenly in Group 2. No serious adverse events were recorded in Group 2 during the investigation. Conclusion. Incorporation of THC into the treatment of patients with AS contributes to the enhanced efficiency of TE. There is a need for further investigations to study the use of muscle relaxants, including THC, in AS in order to elaborate recommendations on how to administer this class of drugs for this disease.