<prompt> All are true about nitrous oxide except ?Laughing gasCauses megaloblastic anemiaCauses diffusion hypoxiaGood muscle relaxant  <response>: Ans. is d i.e., Good muscle relaxant Nitrous oxide N,O It is also called laughing gas. It has good analgesic but poor muscle relaxant activity. Second gas effect and diffusion hypoxia occur with N20 only. N20 is the only anaesthetic repoed to produce hematologic toxicity and neurotoxicity with long term administration. Both toxicities are the result of the interaction of N20 with vit B12. 