<unk>  is an opioid analgesic that is an analogue of fentanyl.<unk>  has similar effects to fentanyl. Side effects of fentanyl analogues are similar to those of fentanyl itself, which include itching, nausea and potentially serious respiratory depression which can be life-threatening.
3-Allylfentanyl
Fentanyl 
Thiopental
Etomidate
Remifentanil
Alfentanil
Medetomidine hydrochloride
Mirfentanil