Fentanyl treats severe, ongoing pain that cannot be controlled with other medicines. This medicine is a narcotic pain reliever. Fentanyl Powder (also known as fentanil) is a potent, synthetic opioid pain medication with a rapid onset and short duration of action. It is a strong agonist at the ?-opioid receptors. Fentanyl is estimated to be between 50 and 100 times as potent as morphine. Product Name: Fentanyl Powder Cas No: 437-38-7 Formula: C22H28N2O Appearance: White powder Purity: above 98.5%