Methemoglobinemia Caused by Volatile Nitrites

Abstract

We report two cases of severe methemoglobinemia caused by accidental oral ingestion of volatile nitrites. Amyl nitrite, isobutyl nitrite, and other volatile nitrites are used as aromas and video head cleaners. However, they are also inhaled and abused to achieve arousal and mood-enhancement. Case 1 was a 26-year-old female who accidentally drank one 10 ml bottle of the inhaled stimulant “KIX®”, the primary ingredient of which is amyl nitrite and experienced dizziness, vomiting, and prominent systemic cyanosis. Arterial blood gas analysis demonstrated a Met-hemoglobin value of 58.3 percent. One hour after intravenous administration of 1.0 mg/kg methylene blue, Met-hemoglobin had decreased to 17.4 percent, and cyanosis had also disappeared. Case 2 was a 45-year-old male who accidentally drank a 9 ml bottle of the inhaled stimulant “RUSH®”, the primary ingredient of which is isobutyl nitrite. After 30 minutes, the subject experienced vomiting, loss of consciousness, prominent systemic cyanosis, and urinary and fecal incontinence. Arterial blood gas analysis demonstrated a Met-hemoglobin value of 54.7 percent. One hour after intravenous administration of 1.0 mg/kg methylene blue, Met-hemoglobin had decreased to 3.8 percent, and cyanosis had also disappeared. Intravenous administration of methylene blue was effective against methemoglobinemia caused by volatile nitrite poisoning. In severe methemoglobinemia, the proportion of oxygenated hemoglobin is reduced and exposes tissues to a hypoxic state in the first hour after treatment, even if oxygen partial pressure by arterial blood gas is high. In the interest of rapid treatment, we believe that pharmacies at emergency treatment facilities should prepare aqueous solutions of methylene blue in advance.