Captagon’s other name is Fenethylline. Looking at the structure of the molecule, one can see that it’s a combination of d-amphetamine and theophylline. It doesn’t appear to be active in its own right, but it’s a prodrug that the liver separates into both of these compounds. When Captagon is taken, it becomes in vivo d-amphetamine and theophylline, and these two new compounds are absorbed into the blood stream, and can now cross the blood brain barrier and become centrally active.
d-amphetamine: We have pretty extensively covered d-amphetamine in our Adderall section. d-amphetamine makes up 75% of Adderall by weight, so we understand the left half of the Captagon molecule. Once broken down and released into the blood stream, the d-amphetamine effects become apparent. This is very similar to Vyvanse, in which d-amphetamine is joined to L-lysine, which is an amino acid. Using the Vyvanse analogy, we can assume that the d-amphetamine release from taking captagon is rate-limited by the liver’s ability to convert the molecule into its constituent parts. This causes an effect similar to a built-in time-release mechanism. I was unable to find the effective half-life, but would expect it to be similar to Vyvanse’s.
Captagon could be considered to be a time-release pill containing Theophylline and Amphetamine. The effects subjectively would be very similar to taking Adderall XR and drinking tea or coffee. The effects are going to be milder than the same dose of Adderall, because half of the molecule being a Xanthine. There are some interesting effects on blood pressure, as Theophylline is a vasodilator while Amphetamine is a vasoconstrictor.