a-PiHP or 4-Me-PVP, a-pyrrolidinoisohexaphenone, 4M-PVP is a new drug, pyrrolidine, developed as an analogue and substitute for MDPV and a-PVP. a-PiHP (α-Pyrrolidinohexiophenone) cathinone, like a-PVP, has a strong effect in chemical studies. Systematic name: 1-fenylo-4-metylo-2- (pirolidyn-1-ylo) pentan-1-on. α-Pyrrolidinohexiophenone is a synthetic stimulant drug cathinone, a longer chain homologue of α-PVP, having additional carbon on the alkyl side chain, and is a structural isomer of pyrovaleron.