Remifentanil is a very short-acting μ-receptor opioid agonist, similar to fentanyl. Remifentanil undergoes metabolism by blood and tissue non-specific esterases, resulting in an extremely rapid clearance that is independent of hepatic or renal function (half-life approximately 3 minutes). The potency of remifentanil is somewhat less than that of fentanyl. Speed of onset of effect is very rapid and is similar to that of alfentanil, approximately 1 to 2 minutes.[1] Its rapid distribution around the body probably leads to a significant risk of apnoea seen when used for painful medical procedures, and its use is not recommended in palliative care.[2]