Metfendrazine (developmental code names HM-11, MO-482), also known as methphendrazine, is an irreversible and nonselective monoamine oxidase inhibitor (MAOI) of the hydrazine family. It was investigated as an antidepressant, but was never marketed.

Metfendrazine, also known as methamphetamine hydrazide, is a phenethylamine, amphetamine, and hydrazine derivative.

It is an analogue and derivative of phenelzine (phenethylamine hydrazide) and pheniprazine (amphetamine hydrazide), as well as of phenethylamine, amphetamine, and methamphetamine.