Tetramethylcyclopropylfentanyl

Tetramethylcyclopropylfentanyl is an opioid analgesic that is an analog of fentanyl and has been sold as a designer drug. == Side effects == Side effects of fentanyl analogs are similar to those of fentanyl itself, which include itching, nausea and potentially serious respiratory depression, which can be life-threatening.