Introduction: For a drug that has been omnipresent for nearly 200 years, nitrous oxide's (N2O) future seems less certain than its illustrious past. Environmental concerns are coming to the fore and may yet outweigh important clinical benefits.
Sources of data: After determining the scope of the review, the authors used PubMed with select phrases encompassing the words in the scope. Both preclinical and clinical reports were considered.
Areas of agreement: The analgesic and anaesthetic advantages of N2O remain despite a plethora of newer agents.
Areas of controversy: N2O greenhouse gas effect and its inhibition of key enzymes involved in protein and DNA synthesis have provided further fuel for those intent on eliminating its further clinical use.
Growing points: The use of N2O for treatment-resistant depression has gained traction.
Areas timely for developing research: Comparative studies for N2O role in combatting the prescription opioid analgesic epidemic may well provide further clinical impetus.