Article Text

Download PDFPDF
Incompatibility of remimazolam besylate with Ringer’s acetate infusion resulting in total occlusion of an intravenous catheter
  1. Mitsuhiro Matsuo1,
  2. Kotaro Okada2,
  3. Yoshinori Onuki2 and
  4. Mitsuaki Yamazaki1
  1. 1Anesthesiology, University of Toyama Faculty of Medicine Graduate School of Medicine and Pharmaceutical Science for Education, Toyama, Japan
  2. 2Laboratory of Pharmaceutical Technology, University of Toyama Faculty of Medicine Graduate School of Medicine and Pharmaceutical Science for Education, Toyama, Japan
  1. Correspondence to Dr Mitsuhiro Matsuo; mmatsuo{at}


Remimazolam besylate is an ultra-short-acting benzodiazepine derivative recently approved in Japan for general anaesthesia. However, less attention has been paid to the compatibility of remimazolam with infusion solutions, and the mechanism underlying the incompatibility remains unknown. The patient was a 65-year-old man who underwent a high tibial osteotomy. After the induction of general anaesthesia using remimazolam solution (5 mg/mL), we noticed precipitate completely blocking the lumen of the intravenous tube connected to a Ringer’s acetate Physio140 drip. The mixture of remimazolam solution (5 mg/mL) with Physio140 solution immediately resulted in the formation of substantial precipitate. Nuclear magnetic resonance analysis revealed that the precipitate was remimazolam. Ultraviolet spectrophotometry revealed that the mixture of remimazolam solution with higher ratios of Physio140 resulted in significantly lower solubility, concomitant with an increase in pH. It would be important to consider the remimazolam concentration and infusion solution pH to avoid the production of precipitates.

  • anaesthesia
  • drug interactions
  • safety

Statistics from


  • Contributors All authors contributed to the study concept and design. MM was the attending anaesthesiologist during the case and prepared the manuscript. KO and YO performed nuclear magnetic resonance and ultraviolet spectrometry. MY supervised manuscript preparation. All authors read and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.