Isocarboxazid

What it is and how it works

Mechanism class: Monoamine Oxidase Inhibitors

Indications

INDICATIONS AND USAGE Marplan is indicated for the treatment of depression. Because of its potentially serious side effects, Marplan is not an antidepressant of first choice in the treatment of newly diagnosed depressed patients. The efficacy of Marplan in the treatment of depression was established in 6-week controlled trials of depressed outpatients. These patients had symptoms that corresponded to the DSM-IV category of major depressive disorder; however, they often also had signs and symptoms of anxiety (anxious mood, panic, and/or phobic symptoms) ( see CLINICAL PHARMACOLOGY ).

Dosage and administration (summary)

DOSAGE AND ADMINISTRATION For maximum therapeutic effect, the dosage of Marplan must be individually adjusted on the basis of careful observation of the patient. Dosage should be started with one tablet (10 mg) of Marplan twice daily. If tolerated, dosage may be increased by increments of one tablet (10 mg) every 2 to 4 days to achieve a dosage of four tablets daily (40 mg) by the end of the first week of treatment. Dosage can then be increased by increments of up to 20 mg/week, if needed and tolerated, to a maximum recommended dosage of 60 mg/day. Daily dosage should be divided into two to four dosages.

Contraindications

CONTRAINDICATIONS Marplan (isocarboxazid) should not be administered in combination with any of the following: MAO inhibitors or dibenzazepine derivatives; sympathomimetics (including amphetamines); some central nervous system depressants (including narcotics and alcohol); antihypertensive, diuretic, antihistaminic, sedative or anesthetic drugs, buproprion HCL, buspirone HCL, dextromethorphan, cheese or other foods with a high tyramine content; or excessive quantities of caffeine.

Warnings and precautions

WARNINGS TO PHYSICIANS Clinical Worsening and Suicide Risk Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide.

Pregnancy

Pregnancy There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antidepressant, including MARPLAN, during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for Antidepressants at 1-844-405-6185 or visiting online at http://womensmentalhealth.org/clini…

Storage and supply

HOW SUPPLIED Marplan tablets 10 mg are peach colored, round and scored with "MARPLAN 10" imprinted on one side and scored on the other. Supplied in bottles of 100 (NDC 72336-032-01). Storage: Store at 77ºF (25ºC); excursions permitted to 59º to 86ºF (15º to 30ºC) . Dispense in a tight, light-resistant container as defined in USP.

Source: Isocarboxazid (Marplan) — US FDA prescribing information, 2026-04-21, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.