4-Chlorophenylisobutylamine (4-CAB, AEPCA), also known as 4-chloro-α-ethylphenethylamine, is an entactogen and stimulant drug of the phenethylamine class.[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, and is actually similar to that of MDMA.[1]
Relative to PCA, 4-CAB is also substantially less effective as a serotonergic neurotoxin.[1] A single 10 mg/kg administration of PCA to rats produces an approximate 80% decrease in serotonin markers as observed 1 week later.[1] In contrast, 11 mg/kg and 22 mg/kg doses of 4-CAB result in only 20% and 50% decreases, respectively.[1] This is once again similar to MDMA which causes a 40-60% reduction with a single 20 mg/kg dose.[2]