This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Remifentanil is : 
Select and explain. 
A. Useful for short painful procedures, B. Metabolized by plasma esterases, C. Equipotent as fentanyl, D. All of these
D: All of these
Answer: D: All of these 
Explanation: Remifentanil is shortest acting opioid due to its metabolism by plasma esterases.
Due to its short duration of action, it is indicated for short-term painful procedures.
Intravenous bolus dosing is not practical because of the short duration of action, rather it is administered by constant i.v. infusion.
Potency is equal to fentanyl and similarly, it can also cause post-operative muscle rigidity.