Self-administered nitrous oxide for the management of incident pain in terminally ill patients: a blinded case series.

The treatment of incident pain in terminally ill cancer patients receiving long-term opioid therapy remains a challenge. Self-administered inhaled nitrous oxide has been used for short-term analgesia in this setting, with mixed results. It is unclear whether nitrous oxide exhibits cross-tolerance with opioids, and there is the possibility of a strong placebo effect in previous unblinded reports.