Isocarboxazid (Marplan): How This MAOI Works, Diet Rules, and When Telehealth Is Enough

Last updated: August 23, 2026

Isocarboxazid, sold as Marplan, is an oral MAOI used for depression after other antidepressants have not done enough. It is not a first-choice start. This guide covers how it works, the usual 10 mg tablet schedule, the tyramine diet, washout rules, and when a video visit can support care versus when you need in-person blood pressure checks or emergency care.

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TL;DR

• Marplan (isocarboxazid) is an irreversible MAOI for depression. DailyMed says it is not an antidepressant of first choice for newly diagnosed patients. See DailyMed Marplan (setid ac387aa0) and MedlinePlus a605036.
• StatPearls MAOIs (NBK539848) (updated December 13, 2025) lists FDA-approved MAOIs as isocarboxazid, phenelzine, selegiline, and tranylcypromine. Isocarboxazid is indicated for MDD after first-line therapy has not worked. Efficacy beyond 6 weeks has not been systematically assessed in randomized trials.
• Tablets are 10 mg, peach, scored, marked MARPLAN 10. DailyMed start: 10 mg twice daily. If tolerated, raise by 10 mg every 2 to 4 days to 40 mg per day by the end of week one. Then you may raise by up to 20 mg per week to a maximum of 60 mg per day, split into 2 to 4 doses. Use caution above 40 mg per day. After a good response, try a slow reduction.
• MedlinePlus: usually 2 to 4 times a day. You may crumble tablets into food or liquid if you cannot swallow them whole. Full benefit may take 3 to 6 weeks. If there is no response by then, continued use is unlikely to help (DailyMed). Do not stop without a plan.
• Boxed warning: suicidality in children, adolescents, and young adults. Marplan is not approved in pediatric patients. Hypertensive crisis can follow high-tyramine foods or certain drugs. DailyMed DEA Schedule: None.
• You must follow a low-tyramine diet and avoid many serotonergic, stimulant, and blood-pressure medicines. MedlinePlus: the drug may remain in the body for 2 weeks after you stop. StatPearls: irreversible MAO recovery often takes about 2 weeks.
• Medicare behavioral telehealth in the home is permanent. The extra in-person visit rule is waived through December 31, 2027. See HHS telehealth policy.
• Klarity Health connects you with 2,000+ licensed providers. Coverage may vary by plan. Verify benefits before you book. If you are in crisis, call or text 988.

On this page

• What is isocarboxazid (Marplan)?
• How this MAOI works
• Who it is for
• Dosing and how to take it
• Tyramine diet and caffeine
• How long it takes to work
• Side effects and safety
• Interactions and washouts
• When telehealth is enough
• How Klarity Health fits
• FAQ

What is isocarboxazid (Marplan)?

Isocarboxazid is a nonselective, irreversible monoamine oxidase inhibitor. MedlinePlus says it treats depression in people who have not been helped by other antidepressants. The brand name is Marplan. DailyMed lists 10 mg film-coated peach tablets from Validus (NDC 30698-032-01). DEA Schedule: None.

DailyMed is explicit: Marplan treats depression, but it is not first choice for newly diagnosed patients because of serious side effects, drug interactions, and diet rules. Two 6-week placebo-controlled outpatient studies supported efficacy. Patients often also had anxiety, panic, or phobic symptoms. Mean dose was about 40 mg per day. Few patients received more than 60 mg per day. Hospitalized, endogenomorphic, and delusional depression have not been adequately studied. Use beyond 6 weeks has not been systematically evaluated in controlled trials, so a clinician who continues it should reassess usefulness over time.

Related Klarity reads: phenelzine (Nardil), tranylcypromine (Parnate), selegiline (Emsam), trazodone, venlafaxine (Effexor), bupropion.

How this MAOI works

Monoamine oxidase breaks down dopamine, norepinephrine, and serotonin. StatPearls describes two forms: MAO-A (serotonin and norepinephrine, mainly in the gut) and MAO-B (phenylethylamine, mainly in basal ganglia and platelets). Both break down dopamine. Isocarboxazid irreversibly inhibits MAO. Enzyme recovery, not the short plasma half-life, sets the washout clock.

StatPearls: peak levels in about 1 to 2 hours with relatively low bioavailability. The liver converts it to hippuric acid. Half-life is about 1.5 to 4 hours. About 42% to 45% of a dose appears in urine within 24 hours, mainly as hippuric acid. Irreversible MAO recovery still takes about 2 weeks.

Who it is for

A licensed clinician decides after a history that covers mood, mania risk, blood pressure, headaches, heart and liver disease, kidney function, pheochromocytoma, pregnancy plans, alcohol, and every medicine and supplement you take.

DailyMed contraindicates confirmed or suspected cerebrovascular defect, cardiovascular disease, hypertension, or a history of headache. StatPearls: do not use in active liver disease or abnormal hepatic function, or in severe renal impairment. None of the FDA MAOIs is approved under age 18. Human pregnancy data for isocarboxazid are limited. StatPearls says isocarboxazid is excreted in human milk and generally warrants stopping either the drug or breastfeeding.

This guide is educational. It is not a diagnosis and it is not a promise that any clinician will prescribe isocarboxazid.

Dosing and how to take it

Follow the label your prescriber writes. Typical DailyMed schedule:

• Start: 10 mg twice daily.
• If tolerated: raise by 10 mg every 2 to 4 days to 40 mg per day by the end of week one.
• Then: raise by up to 20 mg per week if needed, maximum 60 mg per day, divided into 2 to 4 doses.
• Caution above 40 mg per day because higher-dose monitoring data are limited.
• After maximum clinical response: try a slow reduction over several weeks without losing the gain.

MedlinePlus: take it at around the same times each day. Swallow with water or another liquid. If you cannot swallow tablets, you can crumble them and take them with food or liquid. Do not take more, more often, or longer than prescribed. MedlinePlus notes it may be habit-forming in the sense that you should not escalate the dose on your own.

Older adults: StatPearls says there is no formal geriatric dose table, but start carefully and watch for hypotension, cognitive change, and falls.

Tyramine diet and caffeine

Hypertensive crises have occurred after high-tyramine foods. DailyMed tells patients to avoid protein foods in which aging or protein breakdown is used to increase flavor. The label names cheese (especially strong or aged), sour cream, Chianti, sherry, beer (including non-alcoholic beer), liqueurs, pickled herring, anchovies, caviar, liver, canned figs, raisins, bananas or avocados (especially if overripe), chocolate, soy sauce, sauerkraut, fava bean pods, yeast extracts, yogurt, meat extracts, meat prepared with tenderizers, and dry sausage. Do not drink alcohol. Avoid excessive caffeine.

Stop the medicine and get emergency care if you get a sudden severe headache, palpitations, stiff neck, chest tightness, sweating, nausea, or vomiting. DailyMed: palpitations or frequent headaches can be a warning. If a hypertensive crisis occurs, stop Marplan and lower blood pressure immediately. The label discusses slow IV phentolamine 5 mg and external cooling for fever. Do not use parenteral reserpine.

How long it takes to work

DailyMed: some people do not see a useful effect for 3 to 6 weeks. If there is no response by then, continued administration is unlikely to help. StatPearls: antidepressant effects of MAOIs generally appear within 2 to 3 weeks, and people should stay on an antidepressant at least 6 months for maximal benefit. Stopping earlier raises relapse risk. Those two clocks answer different questions: first response versus how long to stay on a working medicine.

Side effects and safety

Common issues include low blood pressure and faintness, drowsiness that can impair driving, and the boxed suicidality risk. Watch for new or worse depression, suicidal thoughts, agitation, panic, insomnia, aggression, or unusual excitement, especially at start and at dose changes. Call or text 988 if you are in crisis.

DailyMed: older adults with dementia-related psychosis are not the labeled population for this antidepressant, and Marplan is not approved in children. StatPearls: get baseline and periodic blood pressure and baseline liver tests because of hepatotoxicity risk with isocarboxazid, phenelzine, and tranylcypromine. Carry an ID card or wristband so other clinicians know you take an MAOI.

Overdose is a medical emergency. StatPearls toxicity review notes first-generation nonselective MAOIs have a low therapeutic index.

Interactions and washouts

DailyMed says do not combine Marplan with other MAO inhibitors or dibenzazepine derivatives; sympathomimetics including amphetamines; some CNS depressants including narcotics and alcohol; antihypertensive, diuretic, antihistamine, sedative, or anesthetic drugs; bupropion; buspirone; dextromethorphan; high-tyramine foods; or excessive caffeine. Combining with blood-pressure medicines can cause marked hypotension.

MedlinePlus: tell every clinician you have taken isocarboxazid in the last 2 weeks before they start a new medicine. StatPearls: irreversible MAO resynthesis takes about 2 weeks. Fluoxetine often needs a longer gap before an MAOI because of its long-lived metabolite. Do not start phenylalanine, tyrosine, or tryptophan supplements without a clinician check. Linezolid and IV methylene blue are MAOI-class stops on many other antidepressant labels.

When telehealth is enough

A video visit can take a full history, review every medicine and supplement, teach the diet, and follow a stable adult who already knows the rules. New starts still need reliable blood-pressure tracking. Chest pain, sudden severe headache, fainting, seizure, high fever with stiff muscles, or suspected overdose need emergency care, not a scheduled video slot.

Medicare behavioral telehealth in the home is permanent. The extra in-person visit rule is waived through December 31, 2027. See HHS telehealth policy.

How Klarity Health fits

Klarity Health connects you with 2,000+ licensed providers. Many visits happen by video. A clinician may discuss whether an MAOI is even appropriate. Many people do better on an SSRI, SNRI, or other later-line option first. Coverage may vary by plan. Self-pay is also an option. Verify benefits before you book.

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FAQ

Is Marplan a controlled substance?

No. DailyMed lists DEA Schedule: None. Diet and drug rules still apply.

Can I start isocarboxazid as my first antidepressant?

DailyMed says no for newly diagnosed patients. Clinicians usually try other classes first because of hypertensive-crisis risk and interactions.

Do I need a tyramine diet on Marplan?

Yes, for the whole course and typically for about 2 weeks after you stop, because enzyme recovery lags the tablet half-life.

How is Marplan different from Emsam?

Emsam is a selegiline skin patch. The 6 mg per 24 hour patch usually does not need a tyramine diet if you use it as directed. Oral isocarboxazid needs the diet at every labeled dose. See the Emsam guide.

Will insurance cover Marplan?

Coverage may vary by plan. Prior authorization is common for later-line antidepressants. Verify benefits before you book. This is not a coverage promise.

Educational only. Not medical advice. If you are in crisis, call or text 988. Coverage varies by plan. Verify benefits before you book.