Pentorex, also known as phenpentermine or α,β-dimethylamphetamine and sold under the brand name Modatrop, is a stimulant drug of the amphetamine family related to phentermine (α-methylamphetamine) which is used as an anorectic to assist with weight loss. It also acts as a diuretic. Pentorex was developed by Nordmark in the 1960s.