Marplan Is an MAOI Antidepressant Used for Treatment-Resistant Depression

Marplan (Isocarboxazid) is a monoamine oxidase inhibitor (MAOI) — a type of antidepressant that works by blocking the enzyme that breaks down mood-regulating brain chemicals like serotonin, norepinephrine, and dopamine. It's prescribed for major depressive disorder in patients who haven't responded to other antidepressants.

If your doctor has mentioned Marplan, or you've come across it while researching treatment options, this guide covers everything you need to know: what it is, how it works, how to take it, who shouldn't take it, and what it costs in 2026.

What Is Marplan?

Here are the basics:

• Brand name: Marplan
• Generic name: Isocarboxazid
• Drug class: Monoamine oxidase inhibitor (MAOI)
• Manufacturer: Validus Pharmaceuticals LLC
• FDA-approved for: Major depressive disorder (specifically treatment-resistant depression)
• Controlled substance: No — Marplan is not a controlled substance
• Generic available: No — there is currently no generic version of Isocarboxazid available in the United States

Marplan belongs to the first generation of antidepressants. MAOIs were among the earliest drugs developed to treat depression, and while newer classes (SSRIs, SNRIs) have largely replaced them as first-line treatments, MAOIs like Marplan remain critically important for patients who don't respond to those newer options.

What Is Marplan Used For?

FDA-Approved Use

Marplan is FDA-approved for the treatment of major depressive disorder — specifically in patients who have not responded to other antidepressant treatments. It's considered a last-line option, meaning doctors typically try SSRIs (like Sertraline or Fluoxetine), SNRIs (like Venlafaxine or Duloxetine), and sometimes tricyclic antidepressants before turning to an MAOI.

Off-Label Uses

Some psychiatrists also prescribe Marplan off-label for:

• Atypical depression (depression with mood reactivity, increased appetite, and excessive sleeping)
• Dysthymic disorder (chronic low-grade depression)
• Panic disorder
• Social phobia
• Other anxiety disorders

MAOIs have historically shown particular effectiveness for atypical depression, which is one reason psychiatrists may consider Marplan even when other medications have failed.

How Is Marplan Taken?

Marplan comes as a 10 mg oral tablet. Here's what a typical dosing schedule looks like:

• Starting dose: 10 mg twice daily
• Dose increases: Your doctor may increase by 10 mg every 2–4 days as tolerated
• Target dose: Usually 40 mg per day by the end of the first week
• Maximum dose: 60 mg per day
• How to take it: By mouth, in 2–4 divided doses throughout the day
• With food: Can be taken with or without food — but you must strictly avoid tyramine-containing foods (more on this below)

It may take several weeks to feel the full therapeutic effect. Don't stop taking Marplan because it doesn't seem to be working right away — give it time, and stay in close contact with your doctor about how you're feeling.

Who Should Not Take Marplan?

Marplan is not safe for everyone. It is contraindicated (should not be used) in patients with:

• Pheochromocytoma (a rare adrenal gland tumor)
• Congestive heart failure
• Severe kidney impairment
• Liver disease or abnormal liver function tests
• History of hepatic disease

Marplan also must never be taken with:

• Other MAOIs (Phenelzine, Tranylcypromine, Selegiline)
• SSRIs (Fluoxetine, Sertraline, Paroxetine, etc.)
• SNRIs (Venlafaxine, Duloxetine)
• Tricyclic antidepressants
• Meperidine and certain other opioids
• Sympathomimetics (Amphetamines, Pseudoephedrine, Phenylephrine)
• Dextromethorphan (found in many cough medicines)
• Bupropion, Buspirone, Carbamazepine, Cyclobenzaprine

For a complete list, read our Marplan drug interactions guide.

Marplan is also contraindicated during pregnancy and is not recommended while breastfeeding. It is not approved for use in children.

The Tyramine-Restricted Diet

This is the big one. While taking Marplan, you must avoid foods high in tyramine — a substance found in aged, fermented, and cured foods. Eating tyramine while on an MAOI can trigger a hypertensive crisis (a dangerous spike in blood pressure).

Foods to avoid include:

• Aged cheeses (Cheddar, Swiss, Parmesan, Brie, Camembert)
• Cured meats (salami, pepperoni, prosciutto)
• Fermented foods (sauerkraut, kimchi, miso, tempeh)
• Soy sauce
• Red wine and tap beer
• Overripe avocados
• Fava beans
• Yeast extracts (Marmite, Vegemite)

Your doctor should provide a comprehensive list. These dietary restrictions must continue for at least 2 weeks after stopping Marplan, because the drug's effects on the MAO enzyme last that long.

How Much Does Marplan Cost?

Marplan is expensive. Here's what you can expect to pay in 2026:

• Cash price: $577–$700 for a 30-day supply (60 tablets of 10 mg)
• Generic: Not available in the US
• Insurance: Coverage varies. Most insurers require prior authorization and step therapy (proof you've tried other antidepressants first).

Ways to Save

• Marplan Co-pay Card: Commercially insured patients may pay as little as $20 per 30-day supply, with savings up to $100 per fill. Not valid for government insurance (Medicare, Medicaid, Tricare).
• Prescription Hope: Offers Marplan for $70/month for qualifying patients.
• Patient assistance: Contact Validus Pharmaceuticals at 1-866-982-5438 for uninsured/underinsured patient assistance options.

For a full breakdown, see our guide to saving money on Marplan.

Final Thoughts

Marplan isn't a first-choice antidepressant — but for people with treatment-resistant depression, it can be exactly what's needed. It's a serious medication that requires commitment: dietary restrictions, careful drug interaction management, and regular follow-ups with your psychiatrist.

If you've been prescribed Marplan and are having trouble finding it, Medfinder can help you locate a pharmacy near you that has it in stock. And if you're still exploring whether Marplan is right for you, talk to a psychiatrist experienced with MAOIs.