Extravasation with methylthioninium chloride.

Methylthioninium chloride is used for multiple treatment purposes and is sometimes administered through peripheral intravenous lines. We highlight the potential adverse effects of methylthioninium chloride extravasation during continuous peripheral intravenous administration. A 38-year-old woman presented to the emergency department with multifactorial hypovolemic and septic shock. She was treated with a continuous peripheral infusion of intravenous methylthioninium chloride for shock refractory to multiple vasopressors. One day after administration commenced, the patient developed blue staining of the left upper arm due to extravasation of methylthioninium chloride proximal to the site of infusion. Further images show its later spread. While reported cases of methylthioninium chloride extravasation are rare, it is our preference that methylthioninium chloride should be administered through a central line in cases of continuous infusion due to the risk of potential toxicity from extravasation.