Severe nitrous oxide use disorder: A case-report

Abstract

Nitrous oxide or N 2 0 is an odorless/colorless gas, also known as laughing gas. Its analgesic properties were used in dentistry or surgery as early as the 19th century. Nowadays, three main uses are described: a medical use, as an adjuvant during anesthetic procedures, always combined with oxygen; a domestic use as a propellant for whipped-cream dispensers; and a diverted use for recreational purposes, in order to achieve a disinhibition, euphoria and perceptual distortions. We report a case of severe N 2 0 use disorder, requiring specialized medical care. A 22 year-old medicine student presented himself to an Addiction Treatment Centre (CSAPA) because of N 2 0 consumption. He had no medical history apart from an irritable bowel syndrome. He denied any drug abuse history and had no medical treatment, despite self-medication trends with tramadol or zopiclone. He discovered N 2 0 three years ago, during student parties. After experiencing the expected effects, he noticed a fast but brief analgesic effect on his bowel pain, leading him to repeat inhalations through balloons filled with whipped-cream chargers. Within a few months, a tolerance appeared and he started inhaling N 2 0 as an anxiolytic. His consumption eventually reached several hundred chargers per month. He began complaining of several side effects (limb paresthesia, asthenia, breathlessness and memory impairment), but was unable to stop N 2 0 consumption because of withdrawal symptoms. Blood tests did not reveal any hematological abnormalities, but a low plasmatic vitamin B12 level. A contrast-enhanced magnetic resonance imaging was normal. The treatment consisted of a regular monitoring with cognitive behavioral therapy, vitamin B12 supplementation and venlafaxine introduction. Nitrous oxide, especially when sold as whipped-cream chargers, is cheap and easily accessible. Its abuse during parties is quite common, especially among student population [1] , [2] . Acute complications described in literature include frost-bite, pneumomediastinum and potentially life-threatening hypoxia. Repeated exposures may lead to neurological (myeloneuropathy) and hematological (megalobastic anemia) symptoms, due to vitamin B12 dysfunction [3] . Appropriate preventive information should be provided, as the users are often unaware of those complications, just as they ignore the risk of addiction with this seemingly harmless inhalant.