4-Fluorodeprenyl, or p-F-deprenyl, also known as fludeprenyl or as N-methyl-N-propargyl-4-fluoroamphetamine, is a stimulant and monoamine oxidase inhibitor (MAOI) of the amphetamine family. It is the 4-fluoro derivative of deprenyl and the racemic form of 4-fluoroselegiline. The drug is metabolized into the stimulants 4-fluoroamphetamine (4-FA) and 4-fluoromethamphetamine (4-FMA) and hence acts in part as a prodrug of these metabolites. Accordingly, it produces methamphetamine-like effects in drug discrimination tests in squirrel monkeys. Like deprenyl and selegiline (<small>L</small>-deprenyl), 4-fluorodeprenyl is additionally a selective and irreversible inhibitor of monoamine oxidase B (MAO-B). The drug was encountered as a novel designer drug in Germany in 2019.