CPI-CG-8, also known as N-methyl-N-(2-indolylethyl)tryptamine, is a "relatively" selective serotonin 5-HT<sub>2C</sub> receptor agonist of the tryptamine family.
At the serotonin 5-HT<sub>2C</sub> receptor, it showed 99.4% binding inhibition (a measure of affinity) at a concentration of 1,000nM, had an activational potency () of 12.46nM, and showed an activational efficacy () of approximately 80%. The pharmacokinetics of CPI-CG-8 in rodents have been studied.
The drug was developed by Collaborations Pharmaceuticals and was derived via modification of the psychedelic drug psilocin using generative machine learning through a platform called MegaSyn. CPI-CG-8 was first described in the scientific literature by 2024. It is of interest for the potential treatment of opioid use disorder and other conditions.