Fenethylline

Fenethylline, also spelled phenethylline, is a synthetic prodrug used as a stimulant and marketed under the brand name Captagon.

History
Fenethylline was invented in 1963 and used for around 25 years as a milder alternative to amphetamines. It was used in applications such as treating "hyperkinetic children" (what would now be referred to as Attention Deficit Hyperactivity Disorder), and also less commonly for treating narcolepsy or as an antidepressant. One of the main advantages of fenethylline was that it does not tend to increase blood pressure to the same extent as amphetamines and so could be used in patients with cardiovascular conditions.

Although fenethylline was considered to have fewer side effects and less potential for abuse than amphetamine, it nevertheless became illegal in most countries in 1986 after being listed by the World Health Organization for international scheduling under the Convention on Psychotropic Substances, even though the actual incidence of fenethylline abuse was quite low.

Pharmacology
Fenethylline is metabolized by the body to form two drugs amphetamine (24.5% of oral dose) and theophylline (13.7% of oral dose), both of which are active stimulants themselves. The physiological effects of fenethylline therefore result from a combination of all three drugs.

Abuse
Abuse of fenethylline as the brand Captagon is most common in Arab countries, and counterfeit versions of the legal drug continue to be available despite now being illegal for 20 years. Many of these counterfeit "Captagon" tablets actually contain other amphetamine derivatives that are easier to produce, but are pressed and stamped to look like Captagon pills. Some Captagon pills analyzed do contain fenethylline however, indicating that illicit production of this drug continues to take place.