This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2017, Subject name: Anaesthesia
The shoest acting opioid is:- 
Select and explain. 
A. Fentanyl, B. Sulfentanil, C. Remifentanil, D. Alfentanyl
C: Remifentanil
Answer: C: Remifentanil 
Explanation: Fentanyl : Supplemental doses are to be given after 30 min only Analogues of feentanyl * Sulfentanyl * Alfentanyl Remifentanil Onset of Action : within 1-2 min IV injection Fades in : 10-15 min Sho action is due to rapid metabolism Metabolized by : Non specific esterases( Extra hepatic,Extra renal ) Safe in fetus, can be used in labour as analgesic