Fenethylline

Fenethylline (BAN, USAN) or fenetylline (INN) is a codrug of amphetamine and theophylline and so a mutual prodrug of both. It is also spelled phenethylline; other names for it are amphetaminoethyltheophylline and amfetyline. The drug has been marketed for use as a psychostimulant under the brand names Captagon, Biocapton, and Fitton. The brand name "Captagon" (or in lowercase as "captagon") is often used generically to describe illicitly produced and sold fenethylline.

In 2023, the UK ministry of foreign affairs estimated that Syria was responsible for about 80% of the global production of Captagon, which, according to then-secretary for the Middle East Tariq Ahmad, was exported from the port of Latakia with the assistance of the Syrian government under the command of Maher al-Assad. The same report issued by the UK government also suggested that "independent experts estimate [the Captagon trade market] could be worth up to $57 billion", and added that "it is worth approximately 3 times the combined trade of the Mexican cartels." Syria analyst and Century International fellow Sam Heller et al. challenged the credibility of the $57bn figure, which is ten times the Syrian annual budget and almost three times the country's GDP. A 2021 report by the New Lines Institute based on the retail value of annual captagon seizures estimated the drug's entire market to be worth at least $5.7bn.

Smuggling of fenethylline became Syria's principal export, exceeding the total of all other exports under the Assad regime during the Syrian civil war (2011–2024). It was the world's largest producer of the drug. A large quantity of Captagon tablets, ready for clandestine export, was captured by anti-Assad forces that took control of Damascus in December 2024.