China has announced that all variants of fentanyl will be treated as controlled substances, after Washington urged Beijing to stop fueling the opioid epidemic in the United States.
Authorities in China already regulate 25 variants of fentanyl, a synthetic opioid linked to thousands of drug overdose deaths in the U.S. But some manufacturers in China, seeking to evade controls, have introduced slight changes to the molecular structure of their drugs, giving them the legal loophole to manufacture and export before the government can assess the products for safety and medical use.