Iproniazid (Euphozid, Iprazid, Ipronid, Ipronin, Marsilid, Rivivol) is a hydrazine drug used as an antidepressant. It acts as an irreversible and nonselective monoamine oxidase inhibitor (MAOI). Though it has been widely discontinued in most of the world, it is still used in France.

Iproniazid was the first antidepressant ever marketed. Originally intended for the treatment of tuberculosis. In 1952, its antidepressant properties were discovered when researchers noted that the patients given isoniazid became "inappropriately happy". Subsequently N-isopropyl addition lead to development as an antidepressant and was approved for use in 1958. It was later withdrawn in 1961 due to the unacceptable incidence of hepatitis and was replaced by less hepatotoxic drugs like isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate).