Penthrane

Methoxyflurane, sold under the brand name Penthrox among others, is an inhaled medication primarily used to reduce pain following trauma.[3][4] It may also be used for short episodes of pain as a result of medical procedures.[2] Onset of pain relief is rapid and of a short duration.[2] Use is only recommended with direct medical supervision.[3] Common side effects include anxiety, headache, sleepiness, cough, and ... [wikipedia]