FRI0133 RELATIONSHIP BETWEEN MELATONIN SERUM LEVELS AND THE EFFICACY OF SELECTIVE SEROTONIN REUPTAKE INHIBITOR PAROXETINE IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background: Numerous clinical and epidemiological studies have established that there is a close relationship between inflammation, chronic pain and psycho-emotional disorders in rheumatoid arthritis [1, 2]. The common pathogenetic mechanism is manifested in the defect of melatonin mediation and cytokine stimulation [3]. Therefore, features of the use of selective serotonin reuptake inhibitors is relevant. Objectives: To study the relationship between serum melatonin level and the efficacy of selective serotonin reuptake inhibitor paroxetine in patients with RA. Methods: A total of 127 RA patients and 71 healthy volunteers were examined. The following information was collected for each patient: medical history data, physical examination results, serum melatonin levels. RA patients were randomly categorized into two treatment groups – 63 and 64 patients. The basic treatment for patients of both groups included nonsteroidal anti-inflammatory drugs, glucocorticoids (equivalent to 10 mg of prednisolone), and disease-modifying antirheumatic drugs (methotrexate, leflunomide or sulfasalazine). To evaluate the effectiveness of treatment, patients of both groups were further divided into three subgroups depending on the serum melatonin level (low level corresponds to 25 percentile, medium - 25-75, high - 75 percentile). First group received paroxetine 20 mg once a day for 12 weeks in addition to the basic treatment. Effectiveness of the treatment was evaluated according to the ACR/EULAR criteria. Results: The mean baseline plasma melatonin levels in RA patients were significantly higher than in the healthy volunteers (26.1±32.7 vs 13.6±4.6 pg/mL at 8 am and 11.5±15.5 vs 3.6±4.6 pg/mL at 20 pm (р<0,001), respectively). A good response to basic treatment was observed in groups with medium and high serum melatonin levels, who received paroxetine (p<0.05). However, patients who did not receive paroxetine gave best response to treatment in group with low serum melatonin levels (p<0.05). Conclusion: Obtained data suggest that the high level of serum melatonin is one of the predictors of resistance for basic RA treatment. The proposed scheme of treatment with addition of paroxetine demonstrated high efficacy concerning the main manifestations of the disease in RA patients with high melatonin serum level. This study demonstrates the possible influence of serotoninergic interactions on the melatoninergic system and their contribution to the pathogenesis of RA. References: [1]Odegård S, Finset A, Mowinckel P, Kvien TK, Uhlig T. Pain and psychological health status over a 10-year period in patients with recent onset rheumatoid arthritis. Ann Rheum Dis. 2007 Sep;66(9):1195-201. doi: 10.1136/ard.2006.064287. Epub 2007 Mar 28. PMID: 17392351; PMCID: PMC1955161. [2]Sturgeon JA, Finan PH, Zautra AJ. Affective disturbance in rheumatoid arthritis: psychological and disease-related pathways. Nat Rev Rheumatol. 2016 Sep;12(9):532-42. doi: 10.1038/nrrheum.2016.112. Epub 2016 Jul 14. PMID: 27411910; PMCID: PMC5449457. [3]Lin GJ, Huang SH, Chen SJ, Wang CH, Chang DM, Sytwu HK. Modulation by melatonin of the pathogenesis of inflammatory autoimmune diseases. Int J Mol Sci. 2013 May 31;14(6):11742-66. doi: 10.3390/ijms140611742. PMID: 23727938; PMCID: PMC3709754. Disclosure of Interests: None declared