Original Contribution Effects of the menstrual cycle on injection pain due to rocuronium Mehtap Honca MD (Staff Anesthesiologist) a, ⁎ , Tarık Purtuloglu MD (Assistant Professor) b , Tevfik Honca MD (Resident) c , Ali Sizlan MD (Associate Professor) b , Suleyman Deniz MD (Staff Anesthesiologist) b , Arzu Kose MD (Assistant Professor) d , Recai Ogur MD (Associate Professor) e , Eyup Horasanlı MD (Associate Professor) a a Department of Anesthesiology and Reanimation, Kecioren Training and Research Hospital, Ankara, Turkey b Department of Anesthesiology and Reanimation, Gulhane Medical Faculty, Ankara, Turkey c Department of Medical Biochemistry, Gulhane Medical Faculty, Ankara, Turkey d Department of Anesthesiology and Reanimation, Kirikkale University School of Medicine, Kirikkale, Turkey e Department of Environmental Health, Gulhane Medical Faculty, Ankara, Turkey Received 1 August 2012; revised 11 February 2013; accepted 15 February 2013 Keywords: Injection pain; Menstrual cycle; Rocuronium Abstract Study Objective: To investigate the effect of the menstrual cycle on rocuronium injection pain. Design: Prospective, randomized, double-blinded study. Setting: Academic medical center. Patients: 80 ASA physical status 1 and 2 women scheduled for elective surgery with general anesthesia. Measurements: Patients were divided into two groups according to their time in the menstrual cycle. Forty patients at days 8 to 12 of the menstrual cycle were considered to be at the follicular phase (Group F), and 40 patients at days 20 to 24 of the menstrual cycle were considered to be at the luteal phase (Group L).Withdrawal movements were recorded. Main Results: Overall frequency of withdrawal movements was significantly higher in Group L than Group F (Pb 0.001). The mean withdrawal movement scorewas 1.77±0.76 in Group L and 0.52±0.67 in Group F. Conclusion: Menstrual cycle phases affect the severity of rocuronium injection pain. Women exhibit greater pain sensitivity from rocuronium injection in the luteal phase than the follicular phase. © 2013 Elsevier Inc. All rights reserved. 1. Introduction Rocuronium bromide is a steroidal nondepolarizing neuromuscular blocking agent [1,2]. Pain due to injection of rocuronium is a common adverse effect and occurs in 50% to 80% of patients [3,4]. A large proportion of women report ⁎ Correspondence: Mehtap Honca, MD, Kecioren Training and Research Hospital, Sanatoryum cad, Pınarbası mah, Ardahan sok, No:25, Kecioren, 06380, Ankara, Turkey. Tel: +90-312-356-9000; fax: +90-312-356-9002. E-mail address: mehtaphonca@hotmail.com (M. Honca). 0952-8180/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jclinane.2013.02.007 Journal of Clinical Anesthesia (2013) xx, xxx–xxx