Serious adverse drug reaction in a woman with hyperemesis gravidarum after first exposure to vitamin B complex containing vitamins B1, B6 and B12 Yoshimine Kuwata 1 †, Shuichi Tsuruoka 2 †, Akihide Ohkuchi 1 , Shigeki Matsubara 1 , Akio Izumi 1 and Mitsuaki Suzuki 1 1 Department of Obstetrics and Gynecology and 2 Department of Pharmacology, Division of Clinical Pharmacology, Jichi Medical University School of Medicine, Tochigi, Japan Abstract We report the case of a pregnant woman who suffered from hypotension after first exposure to intravenous administration of a combination drug containing vitamins B1, B6 and B12 (Vitamedin; Daiichi-Sankyo, Tokyo, Japan). A 27-year-old Japanese woman received an intravenous infusion of fluid containing a vitamin B complex due to hyperemesis gravidarum. Thirty minutes after the start of infusion she was found to be in hypotension. The patient had stupor, general sweating, blood pressure of 82/50 mmHg, and low percutaneous oxygen saturation (SpO2) of 88%. We immediately stopped the infusion, lifted her legs and administered oxygen. Three minutes after these treatments, she quickly recovered to a good general condition.A skin prick test for vitamin B12 was positive, but tests for B1, B6, mannitol and saline were negative, indicating this adverse reaction was one of drug hypersensitivity due to the vitamin B12 in Vitamedin. Patients should be observed carefully immediately after the administration of Vitamedin. Key words: combination drug, drug hypersensitivity, hyperemesis gravidarum, pregnancy, vitamin B. Introduction Drug hypersensitivity is an immune-mediated reaction to a drug. Symptoms range from mild to severe and include skin rash, anaphylaxis and serum sickness. Diagnosis is suggested when a reaction occurs within minutes or hours after drug administration. Tests for immediate type (IgE)-mediated hypersensitivity help diagnose reactions to drugs. A skin prick test (SPT) can detect most allergies. Drug hypersensitivity should be distinguished from toxic and adverse effects that may be expected from the drug and from problems due to drug interactions. Allergy to vitamins B1 or B12, although rare, has been reported previously. 1–11 Although vitamin B complex containing vitamins B1, B6 and B12 (Vitame- din; Daiichi-Sankyo, Tokyo, Japan), is widely used as a treatment for hyperemesis gravidarum in pregnant woman in Japan, no reports have hitherto described the clinical course of a case of Vitamedin-related serious drug hypersensitivity. We report here a pregnant woman who had a serious adverse drug reaction after her first exposure to intravenous infusion of Vitamedin. Case Report A 27-year-old nulliparous Japanese woman visited our hospital due to hyperemesis gravidarum. At eight weeks of gestation, she had appetite loss, nausea and Received: April 1 2008. Accepted: November 10 2008. Reprint request to: Dr Akihide Ohkuchi, Department of Obstetrics and Gynecology, Jichi Medical University School of Medicine, 3311-1Yakushiji, Shimotsuke-shi, Tochigi, 329-0498, Japan. Email: okuchi@jichi.ac.jp †Both authors contributed to this manuscript equally. doi:10.1111/j.1447-0756.2009.01021.x J. Obstet. Gynaecol. Res. Vol. 35, No. 4: 790–793, August 2009 790 © 2009 The Authors Journal compilation © 2009 Japan Society of Obstetrics and Gynecology