Fenethylline

Fenethylline
INN: Fenetylline
Clinical data
Other names	Phenethylline, amphetaminoethyltheophylline, amfetyline
AHFS/Drugs.com	International Drug Names
Routes of; administration	Oral
ATC code	N06BA10 (WHO) ;
Legal status
Legal status	AU: S9 (Prohibited substance); BR: Class A3 (Psychoactive drugs); CA: Schedule III; DE: Anlage III (Special prescription form required); UK: Class C; US: Schedule I;
Identifiers
	IUPAC name (RS)-1,3-dimethyl- 7-[2-(1-phenylpropan-2-ylamino)ethyl]purine- 2,6-dione;
CAS Number	3736-08-1 ;
PubChem CID	19527;
DrugBank	DB01482 ;
ChemSpider	18398 ;
UNII	YZ0N7VL5R3;
KEGG	D07944 ;
ChEBI	CHEBI:135451;
ChEMBL	ChEMBL2111152;
CompTox Dashboard (EPA)	DTXSID50859686 ;
ECHA InfoCard	100.115.827
Chemical and physical data
Formula	C18H23N5O2
Molar mass	341.415 g·mol−1
3D model (JSmol)	Interactive image;
Chirality	Racemic mixture
	SMILES O=C2N(c1ncn(c1C(=O)N2C)CCNC(C)Cc3ccccc3)C;
	InChI InChI=1S/C18H23N5O2/c1-13(11-14-7-5-4-6-8-14)19-9-10-23-12-20-16-15(23)17(24)22(3)18(25)21(16)2/h4-8,12-13,19H,9-11H2,1-3H3 ; Key:NMCHYWGKBADVMK-UHFFFAOYSA-N ;
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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 was 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 fenethylline.

Fenethylline is illegal in most countries. It is produced primarily for illicit use, which takes place mainly in Syria. The illicit global market for the drug was estimated in 2023 to be worth approximately US$57 billion.

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, accounting for about 80% of the global supply. A large quantity of Captagon tablets, ready for clandestine export, was captured by anti-Assad forces that took control of Damascus in December 2024.