Turk Neurosurg, 2016 | 1 Corresponding author: Yahya GUVENC E-mail: yahyaguvenc@yahoo.com.tr Original Investigation DOI: 10.5137/1019-5149.JTN.13037-14.0 Received: 09.10.2014 / Accepted: 24.12.2014 Published Online: 17.02.2016 qr code Yahya GUVENC 1 , Deniz BILLUR 2 , Sevim AYDIN 2 , Ersin OZEREN 3 , Adnan DEMIRCI 4 , Fatih ALAGOZ 5 , Ali DALGIC 5 , Deniz BELEN 5 1 Dr. N. K. Sincan State Hospital, Department of Neurosurgery, Ankara, Turkey 2 Ankara University, School of Medicine, Department of Histology-Embryology, Ankara, Turkey 3 Aksaray State Hospital, Department of Neurosurgery, Aksaray, Turkey 4 Yalova Hospital, Department of Neurosurgery, Yalova, Turkey 5 Ankara Numune Traning and Education Hospital, Department of Neurosurgery, Ankara, Turkey Metamizole Sodium Induces Neural Tube Defects in a Chick Embryo Model ABSTRACT 25%, environmental reasons in 10%, chromosome aberra- tions in 3% and factors such as drugs, infection and radiation exposure during pregnancy in about 3% (10). Metamizole sodium was synthesized in 1920 and production started in Germany in 1922. Metamizole sodium (dipyrone) is a non-opioid analgesic drug used commonly in many countries and also has an antipyretic effect. Metamizole side effects are nausea, vomiting, diarrhea, headache, dizziness, hepatic dysfunction, renal dysfunction, skin reactions (rash, urticaria, erythema), increase in bronchial asthma attacks, anaphylactic shock, agranulocytosis and aplastic anemia █ INTRODUCTION Congenital anomalies are changes in the natural anatomic structure present at birth. Congenital central nervous system anomalies are the most common, followed by congenital cardiovascular abnormalities (9). Neural tube defects (NTD) are heterogeneous and complex congenital anomalies of the central nervous system. The worldwide incidence of neural tube defects varies between 0.1% and 1% (3). The causes of congenital abnormalities are multifactorial. Al- though the cause of the malformation is not known in up to 65–75%, these cases are associated with genetic factors in AIm: The aim of this study was to investigate the effects of metamizole sodium on neural tube development in the early stage chick embryo model that complies with the frst month of embryonic development in mammals. mATERIAl and mEThODS: A total of 40 fertilized chicken eggs were divided into 4 equal groups. The eggs were incubated in the incubator at a temperature of 37.8±2°C with 60±5% humidity. Group A was the control, Group B was administered physiological saline, Group C was administered 30 mg/kg metamizole sodium (based on the therapeutic index range of it used in humans) and Group D was administered 90 mg/kg metamizole sodium. All embryos were removed from the egg at the 48th hour and morphologically and histologically examined. RESUlTS: Normal development was seen and the neural tube was closed in 17 embryos in Groups A and B. A neural tube defect was seen in 2 embryos in group A and in 1 embryo in group B. A neural tube closure defect was seen in all embryos in group C and 9 embryos in group D. There was 1 dead embryo in Group D. CONClUSION: Metamizole sodium was seen to produce a neural tube defect in the chicken embyro model. KEywORDS: Metamizole sodium, Neural tube defects, Chick embryo