Remifentanil (marketed by GlaxoSmithKline and Abbott as Ultiva) is a potent ultra short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications for use in general anesthesia. The use of remifentanil has made possible the use of high dose opioid and low dose hypnotic anesthesia, due to synergism between remifentanil and various hypnotic drugs and volatile anesthetics.