The hydrazine antidepressants are a group of non-selective, irreversible monoamine oxidase inhibitors (MAOIs) which were discovered and initially marketed in the 1950s and 1960s. Most have been withdrawn due to toxicity, namely hepatotoxicity, but a few still remain in clinical use.
Tranylcypromine, a structurally unrelated MAOI introduced around the same time as the hydrazines, was originally advertised as non-hydrazine as a result of its diminished propensity for causing hepatotoxicity.
Legend:‡ = Withdrawn from the market; † = Partially discontinued; Bolded names indicate major drugs.
Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as effective antidepressants, especially for treatment-resistant depression and atypical depression. They are also used to treat panic disorder, social anxiety disorder, Parkinson's disease, and several other disorders.
Phenelzine, sold under the brand name Nardil, among others, is a non-selective and irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class which is primarily used as an antidepressant and anxiolytic. Along with tranylcypromine and isocarboxazid, phenelzine is one of the few non-selective and irreversible MAOIs still in widespread clinical use. It is typically available in 15 mg tablets and doses usually range from 45–90 mg per day.
Tranylcypromine, sold under the brand name Parnate among others, is a monoamine oxidase inhibitor (MAOI). More specifically, tranylcypromine acts as nonselective and irreversible inhibitor of the enzyme monoamine oxidase (MAO). It is used as an antidepressant and anxiolytic agent in the clinical treatment of mood and anxiety disorders, respectively.
Hepatotoxicity implies chemical-driven liver damage. Drug-induced liver injury is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn from the market after approval.
α-Ethyltryptamine, also known as etryptamine, is a psychedelic, stimulant, and entactogenic drug of the tryptamine class. It was originally developed and marketed as an antidepressant under the brand name Monase by Upjohn in the 1960s.
Isocarboxazid is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class used as an antidepressant. Along with phenelzine and tranylcypromine, it is one of only three classical MAOIs still available for clinical use in the treatment of psychiatric disorders in the United States, though it is not as commonly employed in comparison to the others.
Nialamide is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class that was used as an antidepressant. It was withdrawn by Pfizer several decades ago due to the risk of hepatotoxicity.
Iproniazid is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class. It is a xenobiotic that was originally designed to treat tuberculosis, but was later most prominently used as an antidepressant drug. However, it was withdrawn from the market because of its hepatotoxicity. The medical use of iproniazid was discontinued in most of the world in the 1960s, but remained in use in France until its discontinuation in 2015.
Iproclozide is an irreversible and selective monoamine oxidase inhibitor (MAOI) of the hydrazine chemical class that was used as an antidepressant, but has since been discontinued. It has been known to cause fulminant hepatitis and there have been at least three reported fatalities due to administration of the drug.
Pheniprazine is an irreversible and nonselective monoamine oxidase inhibitor (MAOI) of the hydrazine chemical class that was used as an antidepressant in the 1960s. It was also used in the treatment of angina pectoris and schizophrenia. Pheniprazine has been largely discontinued due to toxicity concerns such as jaundice, amblyopia, and optic neuritis.
Mebanazine is a monoamine oxidase inhibitor (MAOI) of the hydrazine chemical class that was previously used as an antidepressant in the 1960s, but has since been withdrawn due to hepatotoxicity.
Metfendrazine, also known as methphendrazine, is an irreversible and nonselective monoamine oxidase inhibitor (MAOI) of the hydrazine chemical class. It was investigated as an antidepressant, but was never marketed.
Phenoxypropazine is an irreversible and non-selective monoamine oxidase inhibitor (MAOI) of the hydrazine family. It was introduced as an antidepressant in 1961, but was subsequently withdrawn in 1966 due to hepatotoxicity concerns.
Pivhydrazine, also known as pivalylbenzhydrazine and pivazide, is an irreversible and non-selective monoamine oxidase inhibitor (MAOI) of the hydrazine family. It was formerly used as an antidepressant in the 1960s, but has since been discontinued.
Safrazine (Safra) is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class that was introduced as an antidepressant in the 1960s, but has since been discontinued.
Benmoxin, also known as mebamoxine, is an irreversible and nonselective monoamine oxidase inhibitor (MAOI) of the hydrazine class. It was synthesized in 1967 and was subsequently used as an antidepressant in Europe, but is now no longer marketed.
Octamoxin, also known as 2-octylhydrazine, is an irreversible and nonselective monoamine oxidase inhibitor (MAOI) of the hydrazine class that was used as an antidepressant in the 1960s but is now no longer marketed.
Cimemoxin (INN), or cyclohexylmethylhydrazine, is a hydrazine monoamine oxidase inhibitor (MAOI) antidepressant which was never marketed.
Domoxin (INN) is a hydrazine derivative monoamine oxidase inhibitor (MAOI) antidepressant which was never marketed.
Carbenzide (INN), also known as carbazic acid, is a hydrazine derivative monoamine oxidase inhibitor (MAOI) antidepressant which was never marketed.