[Problems in hospital preparation of acute poisoning antagonist (methylene blue injection)]

Since some antagonists or antidotes in cases of acute poisoning are not commercially available in Japan, in many hospitals they are prepared on their premises for clinical use. However, no specific legislation for the procedures of quality assurance and informed consent of these hospital-prepared products as yet exists. Further, the standard procedures for clinical use of the hospital-prepared products have yet to be established. For the treatment of patients with methemoglobinemia, we prepared methylene blue for injectable use in our hospital. In this paper, we describe our procedures ranging from its preparation to clinical use of this product. Methylene blue injection was prepared by using reagent-grade chemicals. The quality of hospital-prepared methylene blue injection was examined in accordance with the United States Pharmacopoeia. The contents of methylene blue injection remained constant at room temperature during storage for 12-month. The sterility testing also gave negative results during the same period. In order to obtain approval for its clinical use by the in-hospital ethical committee, relevant documents such as instructions for the preparation method, product information on safety usage and consent form were created. After these procedures, clinical applications of methylene blue injection were finally initiated.