4-Chlorophenylisobutylamine (4-CAB, AEPCA), also known as 4-chloro-α-ethylphenethylamine, is an entactogen and stimulant drug of the phenethylamine, amphetamine, and phenylisobutylamine families.

[1] It is an analogue of para-chloroamphetamine (PCA) where the alpha position methyl has been replaced with an ethyl group.

[1] In comparison to PCA, 4-CAB is approximately 2- and 5-fold less potent at inhibiting the reuptake of serotonin (IC50 = 330 nM) and dopamine (IC50 = 2,343 nM), respectively, and is about 3-fold less potent in substituting for MDMA in animals in drug discrimination assays.

[1] Though its dopaminergic activity is significantly attenuated compared to PCA, unlike the case of MBDB, it is not abolished[clarification needed], and is actually similar to that of MDMA.

[1] A single 10 mg/kg administration of PCA to rats produces an approximate 80% decrease in serotonin markers as observed 1 week later.