Fentanyl is an opioid analgesic, first synthesized in Belgium after the late 1950s. Its analgesic potential is about 80 times that of morphine. It was introduced into medical practice in the 1960s as an intravenous anesthetic. Fentanyl has an LD50 of 3.1 milligrams per kilogram in rats. The LD50 in humans is unknown. Fentanyl is in most countries considered a controlled substance drugs.
The pharmaceutical industry has developed several analogues of fentanyl:
Stable chronic pain, severe resistant to other analgesics and cancer origin (nociceptive pain).
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