Most potent analgesic:

Ref: Goodman & Gillman 13th ed. P 376* Fentanyl citrate and sufentanil citrate are congeners of fentanyl and are considered as potent analgesics* After systemic delivery:# Fentanyl is about 100 times more potent than morphine# Sufentanil is about 1000 times more potent than morphine* Time to peak analgesic effect after IV administration: 5 minutes* These drugs are well known to be used as epidural analgesic.