Carfentanil or carfentanyl is an analog of the synthetic opioid analgesic fentanyl. It is 10,000 times more potent than morphine, making it among the most potent commercially used opioids.

Molar mass: 394.5006 g/mol
CAS ID: 59708-52-0
Formula: C24H30N2O3
Biological half-life: 7.7 hrs
Trade name: Wildnil
ChemSpider ID: 55986

What is the use of carfentanil?
Carfentanil or carfentanyl (Wildnil) is an analogue of the popular synthetic opioid analgesic fentanyl, and is one of the most potent opioids known (also the most potent opioid used commercially). … Carfentanil is intended for large-animal use only as its extreme potency makes it inappropriate for use in humans.
 
What is the strongest opioid in the world?
Codeine is only about 1/10th as powerful as morphine. Opioids more powerful thanmorphine include hydromorphone (Dilaudid) and oxymorphone (Opana). But the strongest opioid in community use is fentanyl which, in its intravenous form, is 70 to 100 times more potent than morphine
 
What are the side effects of carfentanil?
They include:
Absent or shallow breathing.
Pinned or pinpoint pupils.
Nausea or vomiting.
Lethargy, dizziness or sedation.
Clammy, cold skin.
Loss of consciousness.
Absent or weak pulse and/or heart failure.