Street variant. The dosage needed to get high or overdose is so small that its much easier to smuggle in compared to other drugs
AFAIK the medically its only really used for anesthesia which is usually used under controlled conditions and makes responding to very easy, especially when there’s OTC drugs that reverse opioid overdoses, though fentanyl can take multiple dosages to reverse
It’s so bad they revised how they were measuring it to make it look better.
And then it continued to go up anyway