[{"text_idx": "#000001", "text": "Fu-F (Furanyl-fentanyl) is an opioid analgesic that is an analog of fentanyl and has been sold as a designer drug. It has an ED50 value of 0.02 mg/kg in mice. This makes it approximately one fifth as potent as fentanyl."}, {"text_idx": "#000003", "text": "There are no reviews yet."}]