isocarboxazid isocarboxazid isocarboxazid (marplan, marplon, enerzer) 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. isocarboxazidclinical datatrade namesmarplanahfs/drugs.comconsumer drug informationmedlineplusa605036pregnancycategory c (usa) routes ofadministrationoralatc coden06af01 (who) legal statuslegal status au: s4 (prescription only) in general: ℞ (prescription only) pharmacokinetic databioavailabilitylow, peak at 1-2 hmetabolismliver (carboxylesterase)metaboliteshippuric acidelimination half-life1.5-4hexcretionurineidentifiers iupac name n′-benzyl-5-methylisoxazole-3-carbohydrazide cas number59-63-2 ypubchem cid3759iuphar/bps7204drugbankdb01247 ychemspider3628 yunii34237v843tkeggd02580 ychemblchembl1201168 ncomptox 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) ykey:xkfpypqqhfexrz-uhfffaoysa-n y ny (what is this?) (verify) isocarboxazid is primarily used to treat mood and anxiety disorders. it has also been investigated in the treatment of schizophrenia, parkinson's disease and other dementia-related disorders. isocarboxazid, as well as other maois, increase the levels of the monoamine neurotransmitters serotonin, dopamine, norepinephrine, epinephrine, melatonin, phenethylamine in the brain. 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maois, including isocarboxazid, are used only rarely due to prominent food and drug interactions and have been largely superseded by newer antidepressants such as the selective serotonin reuptake inhibitors (ssris).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.