Synthetic psychoactive drugs have become a serious public health threat in recent years. This is particularly true of the fentanyls, a large family of synthetic opioids, which can be up to 10,000 times more potent than morphine. Synthetic opioids are highly addictive and, because of their potency, often prove fatal: among the roughly 72,000 drug overdose deaths in the US in 2017, some 30,000 were related to synthetic opioids.