Isocarboxazid

Antidepressant

C (USA)

Routes of
administrationOralATC code

N06AF01 (WHO)

AU: S4 (Prescription only)
BR: Class C1 (Other controlled substances)^[2]
US: WARNING^[1]
In general: ℞ (Prescription only)

Pharmacokinetic dataBioavailabilityLow, peak at 1-2 h^[3]MetabolismLiver (Carboxylesterase^[5])MetabolitesHippuric acid^[4]Elimination half-life1.5-4h^[3]ExcretionUrineIdentifiers

IUPAC name

N′-benzyl-5-methylisoxazole-3-carbohydrazide

CAS Number

59-63-2^Y

PubChem CID

3759

IUPHAR/BPS

7204

DrugBank

DB01247^Y

ChemSpider

3628^Y

UNII

34237V843T

KEGG

D02580^Y

ChEMBL

ChEMBL1201168^N

CompTox Dashboard (EPA)

DTXSID4023171

ECHA InfoCard100.000.399

Chemical and physical dataFormulaC₁₂H₁₃N₃O₂Molar mass231.255 g·mol⁻¹3D model (JSmol)

Interactive image

SMILES

O=C(NNCc1ccccc1)c2noc(c2)C

InChI

InChI=1S/C12H13N3O2/c1-9-7-11(15-17-9)12(16)14-13-8-10-5-3-2-4-6-10/h2-7,13H,8H2,1H3,(H,14,16)^Y
Key:XKFPYPQQHFEXRZ-UHFFFAOYSA-N^Y

^NY (what is this?) (verify)

Isocarboxazid (Marplan, Marplon, Enerzer) is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class used as an antidepressant.^[6] 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,^[7]^[8] though it is not as commonly employed in comparison to the others.^[7]^[8]

Isocarboxazid is primarily used to treat mood and anxiety disorders. It has also been investigated in the treatment of schizophrenia,^[9] Parkinson's disease and other dementia-related disorders.^[10]

Isocarboxazid, as well as other MAOIs, increase the levels of the monoamine neurotransmitters serotonin, dopamine, norepinephrine, epinephrine, melatonin, phenethylamine in the brain.^[11]

Classical MAOIs, including isocarboxazid, are used only rarely due to prominent food and drug interactions and have been largely superseded by newer antidepressants such as the selective serotonin reuptake inhibitors (SSRIs). The cause of the interactions is because MAOIs inhibit the metabolism of dietary amines (e.g., tyramine) and the monoamine neurotransmitters. In combination with other drugs that increase the levels of the monoamine neurotransmitters such as the SSRIs, or with certain foods high in dietary amines such as aged cheeses, MAOIs can produce dangerous elevations of monoamine neurotransmitters resulting in potentially life-threatening syndromes such as hypertensive crisis and serotonin syndrome.

References

^ "FDA-sourced list of all drugs with black box warnings (Use Download Full Results and View Query links.)". nctr-crs.fda.gov. FDA. Retrieved 22 Oct 2023.
^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-16.
^ ^a ^b Owens DC, Johnstone EC, Lawrie SM (January 2010). "Clinical psychopharmacology.". Companion to psychiatric studies. pp. 227–294. doi:10.1016/B978-0-7020-3137-3.00011-5. ISBN 9780702031373.
^ "Reaction: Isocarboxazid to 1 product". go.drugbank.com. Retrieved 27 October 2021.
^ Moroi K, Kuga T (April 1982). "Inhibitory effect of leptophos on carboxylesterase (isocarboxazid amidase) in rat liver". Toxicology Letters. 11 (1–2): 81–85. doi:10.1016/0378-4274(82)90110-2. PMID 6178187.
^ Fagervall I, Ross SB (April 1986). "Inhibition of monoamine oxidase in monoaminergic neurones in the rat brain by irreversible inhibitors". Biochemical Pharmacology. 35 (8): 1381–1387. doi:10.1016/0006-2952(86)90285-6. PMID 2870717.
^ ^a ^b Rosenberg D (21 August 2013). Pocket Guide For The Textbook Of Pharmacotherapy For Child And Adolescent Psychiatric Disorders. Routledge. pp. 176–. ISBN 978-1-134-86002-9.
^ ^a ^b Labbate LA, Fava M, Rosenbaum JF, Arana GW (28 March 2012). Handbook of Psychiatric Drug Therapy. Lippincott Williams & Wilkins. pp. 99–. ISBN 978-1-4511-5307-1.
^ Darling HF (October 1959). "Isocarboxazid (marplan) in ambulatory psychiatric patients". The American Journal of Psychiatry. 116 (4): 355–356. doi:10.1176/ajp.116.4.355. PMID 13814129.
^ Riederer P, Laux G (March 2011). "MAO-inhibitors in Parkinson's Disease". Experimental Neurobiology. 20 (1). Experimental Neurology: 1–17. doi:10.5607/en.2011.20.1.1. PMC 3213739. PMID 22110357.
^ Volz HP, Gleiter CH (November 1998). "Monoamine oxidase inhibitors. A perspective on their use in the elderly". Drugs & Aging. 13 (5): 341–55. doi:10.2165/00002512-199813050-00002. PMID 9829163. S2CID 71158339.

Antidepressants (N06A)

Specific reuptake inhibitors and/or receptor modulators

SSRIsTooltip Selective serotonin reuptake inhibitors	Citalopram Escitalopram Fluoxetine^# Fluvoxamine Indalpine^‡ Paroxetine Sertraline Zimelidine^‡
SNRIsTooltip Serotonin–norepinephrine reuptake inhibitors	Desvenlafaxine Duloxetine Levomilnacipran Milnacipran Tofenacin Venlafaxine
NRIsTooltip Norepinephrine reuptake inhibitors	Atomoxetine Reboxetine Viloxazine
NDRIsTooltip Norepinephrine–dopamine reuptake inhibitors	Amineptine^‡ Bupropion Nomifensine^‡
NaSSAsTooltip Noradrenergic and specific serotonergic antidepressants	Mianserin Mirtazapine Setiptiline
SARIsTooltip Serotonin antagonist and reuptake inhibitors	Etoperidone Nefazodone Trazodone
SMSTooltip Serotonin modulator and stimulators	Vilazodone Vortioxetine
Others	Agomelatine Amisulpride Dextromethorphan/bupropion Esketamine Etryptamine^‡ Gepirone Indeloxazine Flupentixol Ketamine^§ Medifoxamine^‡ Metryptamine^‡ Oxaflozane^‡ Pivagabine^‡ Tandospirone Teniloxazine Tianeptine

Tricyclic and tetracyclic antidepressants

TCAsTooltip Tricyclic antidepressants	Amineptine^‡ Amitriptyline^# Amitriptylinoxide Amoxapine Butriptyline^‡ Clomipramine^# Demexiptiline^‡ Desipramine Dibenzepin Dimetacrine^‡ Dosulepin Doxepin Imipramine Imipraminoxide^‡ Iprindole^‡ Lofepramine Melitracen Metapramine^‡ Nitroxazepine Nortriptyline Noxiptiline Opipramol Pipofezine Propizepine^‡ Protriptyline Quinupramine^‡ Tianeptine Trimipramine
TeCAsTooltip Tetracyclic antidepressants	Maprotiline Mianserin Mirtazapine Setiptiline
Others	Tiazesim

Monoamine oxidase inhibitors

Non-selective	Irreversible: Benmoxin^‡ Iproclozide^‡ Iproniazid^‡ Isocarboxazid Isoniazid^# Linezolid^# Mebanazine^‡ Nialamide^‡ Octamoxin^‡ Phenelzine Pheniprazine^‡ Phenoxypropazine^‡ Pivhydrazine^‡ Safrazine^‡ Tedizolid Tranylcypromine Reversible: Caroxazone^‡ Mixed: Bifemelane
MAO_ATooltip Monoamine oxidase A-selective	Reversible: Eprobemide Metralindole Minaprine^‡ Moclobemide Pirlindole Tetrindole Toloxatone
MAO_BTooltip Monoamine oxidase B-selective	Irreversible: Selegiline

Adjunctive therapies
Atypical antipsychotics (aripiprazole, brexpiprazole, lurasidone, olanzapine, quetiapine, risperidone) Buspirone Lithium (lithium carbonate, lithium citrate) Thyroid hormones (triiodothyronine (T₃), levothyroxine (T₄))

Miscellaneous
Ademetionine (SAMe) GABAkine neurosteroids (brexanolone, zuranolone) Hypericum perforatum (St. John's Wort) Oxitriptan (5-HTP) Rubidium chloride (RbCl) Tryptophan

^#WHO-EM
^‡Withdrawn from market
Clinical trials:
- ^†Phase III
- ^§Never to phase III

Monoamine metabolism modulators

Non-specific

AAADTooltip Aromatic L-amino acid decarboxylase

Substrates→Products: L-DOPA (levodopa)→Dopamine
5-HTP→Serotonin
L-Histidine→Histamine
Phenylalanine→Phenethylamine
L-Tyrosine→Tyramine
Tryptophan→Tryptamine

MAOTooltip Monoamine oxidase

Substrates→Products (with ALDHTooltip Aldehyde dehydrogenase/ALRTooltip ALR): Epinephrine (adrenaline)→DHMA Metanephrine→MHPG/VMA Norepinephrine (noradrenaline)→DHMA Normetanephrine→MHPG/VMA Dopamine→DOPAC 3-Methoxytyramine→HVA Serotonin→5-HIAA Inhibitors: Non-selective: Benmoxin Caroxazone Echinopsidine Furazolidone Guineesine Hydralazine Indantadol Iproclozide Iproniazid Isocarboxazid Isoniazid Linezolid Mebanazine Metfendrazine Nialamide Octamoxin Paraxazone Phenelzine Pheniprazine Phenoxypropazine Pivhydrazine Procarbazine Safrazine Tranylcypromine
Inhibitors: MAO-A-selective: Amiflamine Bazinaprine Befloxatone Brofaromine Cimoxatone Clorgiline CX157 (Tyrima) Eprobemide Esuprone Harmala alkaloids (e.g., harmine, harmaline, harman, norharman, tetrahydroharmine) Methylene blue Metralindole Minaprine Moclobemide Pirlindole Sercloremine Tetrindole Toloxatone
Inhibitors: MAO-B selective: Adarigiline Almoxatone D-Deprenyl Ethanol Ladostigil Lazabemide Milacemide Mofegiline Nicotine Pargyline^‡ Rasagiline Safinamide Selegiline (L-Deprenyl) Sembragiline

Phenethylamines
(dopamine, epinephrine,
norepinephrine)

PAHTooltip Phenylalanine hydroxylase	Substrates→Products: Phenylalanine→Tyrosine Inhibitors: 3,4-Dihydroxystyrene
THTooltip Tyrosine hydroxylase	Substrates→Products: Tyrosine→L-DOPA (levodopa) Inhibitors: 2-Hydroxyestradiol 2-Hydroxyestrone 3-Iodotyrosine Aquayamycin Bulbocapnine Metirosine Oudenone
DBHTooltip Dopamine beta-monooxygenase	Substrates→Products: Dopamine→Norepinephrine (Noradrenaline) Inhibitors: Bupicomide Disulfiram Dopastin Fusaric acid Nepicastat Phenopicolinic acid Tropolone
PNMTTooltip Phenylethanolamine N-methyltransferase	Substrates→Products: Norepinephrine (noradrenaline)→Epinephrine (adrenaline) Inhibitors: CGS-19281A SKF-64139 SKF-7698
COMTTooltip Catechol-O-methyl transferase	Substrates→Products: Dopamine→3-Methoxytyramine DOPAC→Homovanillic acid Norepinephrine→Normetanephrine Epinephrine→Metanephrine DOPEG→MOPEG DOMA→VMA 2-Hydroxyestradiol→2-Methoxyestradiol 2-Hydroxyestrone→2-Methoxyestrone 4-Hydroxyestradiol→4-Methoxyestradiol 4-Hydroxyestrone→4-Methoxyestrone Inhibitors: 2-Hydroxyestradiol 2-Hydroxyestrone Entacapone Neluxicapone Nitecapone Opicapone Quinalizarin Tolcapone

Tryptamines
(serotonin, melatonin)

TPHTooltip Tryptophan hydroxylase	Substrates→Products: Tryptophan→5-HTP Inhibitors: AGN-2979 Fenclonine (PCPA) Telotristat ethyl
AANATTooltip Serotonin N-acetyl transferase	Substrates→Products: Serotonin→N-Acetylserotonin
ASMTTooltip Acetylserotonin O-methyltransferase	Substrates→Products: N-Acetylserotonin→Melatonin

Histamine

HDCTooltip Histidine decarboxylase	Substrates→Products: L-Histidine→Histamine Inhibitors: Catechin Alpha-Fluoromethylhistidine Histidine methyl ester Meciadanol Naringenin Tritoqualine
HNMTTooltip Histamine N-methyltransferase	Substrates→Products: Histamine→N-Methylhistamine Inhibitors: Amodiaquine Diphenhydramine Harmaline Metoprine Quinacrine SKF-91488 Tacrine
DAOTooltip Diamine oxidase	Substrates→Products: Histamine→Imidazole acetic acid Inhibitors: Pimagedine (aminoguanidine)

See also: Receptor/signaling modulators • Adrenergics • Dopaminergics • Melatonergics • Serotonergics • Monoamine reuptake inhibitors • Monoamine releasing agents • Monoamine neurotoxins

v t e Hydrazines
4-PTSC Acylhydrazine ADH Adjudin Agaritine Benmoxin Cadralazine Carbazide Carbidopa Carbohydrazide Daminozide Dihydralazine DNPH Endralazine Gyromitrin HBT Hydralazine Hydrazide Hydrazine Hydrazone Iproclozide Iproniazid Isocarboxazid Isoniazid Mebanazine Metfendrazine MMH Nialamide Octamoxin PEH Phenelzine Pheniprazine Phenoxypropazine Phenylhydrazine Pildralazine Pimagedine Pivalylbenzhydrazine Procarbazine Safrazine Semicarbazide Semicarbazone SDMH Tetrafluorohydrazine UDMH

Hydrazines