The most potent analgesic agent is:
Sulfentanil is 5 times more potent than Fentanyl.Alfentanil and remifentanil are faster acting and recovery is rapid. Above three drugs are congeners of Fentanyl. Ref: KD Tripathi 8th ed.
Fentanyl
Sufentanil
Remifentanil
Allentanil
Central Nervous system