THU0533 IMPAIRED PLATELET FUNCTIONS IN PATIENTS TREATED WITH COLCHICINE

Background Colchicine has been used in the treatment of Familial Mediterranean Fever (FMF) since 1972. Apart from the inhibiting mitosis in all cells, colchicine has an anti-inflammatory effect by inhibiting activation and migration of neutrophils. Colchicine is a safe drug at recommended doses, but it can cause rare side effects including hematological findings such as lymphopenia, thrombocytopenia and neutropenia. Objectives In this study we aimed to define the adverse effect of colchicine on platelet function and its clinical relevance. Methods A total of 220 FMF patients between June 2016-2017, followed at Hacettepe University Pediatric Rheumatology Department and were on colchicine treatment for at least one year, were included to the study. Results Among the selected 220 FMF patients, 100 of them (54% female) described hematological symptoms when questioned in detail. The mean age of these patients was 11.74 ± 4.86 years. The mean cumulative colchicine exposure was 5.7±3.8 years. The most common referral symptom was frequent epistaxis (79%) followed by easy bruising (69%), and menstrual disorder including prolonged or heavy menstrual bleeding (21.8% among female patients). Among these 100 patients, 36 of them had prolonged bleeding time and impaired platelet aggregation test. Patients who had abnormal platelet function tests (the group with abnormal bleeding time) were receiving higher colchicine doses (median 0.05 vs 0.03 mg/kg/day; p:0.001) compared to the patients who had normal platelet function tests (bleeding time normal group) However there were no significant difference in terms of cumulative colchicine exposure (median 6.5 vs 4.5 years; p:0.07) and total platelet counts (median 288500 vs 279000/mm3; p:0.61). Patients with abnormal platelet function tests also had more epistaxis (47% vs 7%; p Conclusion In our study, we have shown prolonged bleeding time for the first time in the literature. Colchicine may cause microtubule inhibition in platelets as well as in other cells and impair platelet function. Further prospective studies are needed to clarify the significance of this side effect. Reference [1] Padeh S, Gerstein M, Berkun Y. Colchicine is a safe drug in children with familial Mediterranean fever. J Pediatr 2012;161(6):1142-1146. Disclosure of Interests Ozlem Şatirer: None declared, Selcan Demir: None declared, Erdal Sag: None declared, Armagan Keskin: None declared, Yelda Bilginer: None declared, Şule Unal: None declared, Seza Ozen Consultant for: Seza Ozen is receiving consultancy fees from Novartis, Speakers bureau: Roche