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Marplan

isocarboxazid
Used for Depression

Marplan, the brand name for isocarboxazid, is a monoamine oxidase inhibitor (MAOI). It's used to treat depression in adults. But it's usually not the first choice for depression because of the risk of side effects. There are also certain foods to avoid and interactions with other medications. Marplan (isocarboxazid) comes as a tablet you take by mouth 2 to 4 times a day. The dosage is typically started low and is slowly raised based on how well it works and if you have side effects. Some side effects can include sleepiness, headaches, and a dry mouth.

Reviewed by:Last reviewed on April 21, 2025
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What is Marplan (isocarboxazid)?

What is Marplan (isocarboxazid) used for?

How Marplan (isocarboxazid) works

Marplan (isocarboxazid) is a monoamine oxidase inhibitor (MAOI). It works by blocking a protein in the body called MAO. This prevents MAO from breaking down dopamine, serotonin, and norepinephrine in the brain.

By blocking MAO, Marplan (isocarboxazid) helps raise the levels of these chemicals in the brain. This helps regulate mood and treat symptoms of depression.

When does Marplan (isocarboxazid) start working?Time passed since treatment started:
HOURS
DAYS
WEEKS
Full effect
MONTHS

Drug facts

Common BrandsMarplan
Drug ClassMAOI
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
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Side effects of Marplan (isocarboxazid)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Dizziness (29%)
  • Headache (15%)
  • Dry mouth (9%)
  • Constipation (7%)
  • Nausea (6%)
  • Sleep problems (5%)

Less Common Side Effects

Marplan (isocarboxazid) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

  • Suicidal thoughts or behaviors
  • Extremely high blood pressure: seizure, chest pain, severe headache, frequent headaches, confusion, blurry vision, anxiety, trouble breathing
  • Serotonin syndrome: hallucinations, seizure, confusion, restlessness, shivering, sweating, high fever, headache, racing heart, muscle stiffness or twitching, tremor

Source: DailyMed

The following Marplan (isocarboxazid) side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

chills

cold sweats

confusion

difficult urination

dizziness, faintness, or lightheadedness when getting up from lying or sitting position

fainting

fast, irregular, pounding, or racing heartbeat or pulse

fear or nervousness

heavy feeling

increased need to urinate

passing urine more often

restlessness

shakiness in the legs, arms, hands, or feet

sudden jerky movements of the body

sweating

trembling or shaking of the hands or feet

trouble sitting still

Incidence not known

Agitation

burning while urinating

change in consciousness

decrease in frequency of urination

decrease in urine volume

decreased urine output

depression

difficulty in passing urine (dribbling)

dizziness

false or unusual sense of well-being

headache

hostility

irritability

loss of bladder control

loss of consciousness

muscle twitching

nausea

need to keep moving

numbness or tingling of the hands, feet, or face

rapid weight gain

seeing, hearing, or feeling things that are not there

seizures

shakiness and unsteady walk

stupor

swelling of the face, ankles, or hands

unsteadiness, trembling, or other problems with muscle control or coordination

unusual tiredness or weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Decreased interest in sexual intercourse

drowsiness

inability to have or keep an erection

loss in sexual ability, desire, drive, or performance

relaxed and calm

sleepiness

sleeplessness

trouble sleeping

unable to sleep

unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

Incidence not known

Black tongue

blurred vision

change in vision

impaired vision

increased sensitivity of the skin to sunlight

itching

raised, dark red, wart-like spots on the skin, especially when used on the face

redness or other discoloration of the skin

severe sunburn

skin rash

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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Pros and cons of Marplan (isocarboxazid)

Pros

  • Possible option for depression when other antidepressants haven't worked well
  • Taken by mouth
  • Can take with or without food

Cons

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Pharmacist tips for Marplan (isocarboxazid)

pharmacist
  • Marplan (isocarboxazid) can take a few weeks to start working. If you don't start to feel any better after 3 to 6 weeks, talk to your prescriber. There might be other options for you.
  • Take Marplan (isocarboxazid) with or without food. If the medication is hurting your stomach, try taking it with food next time to help. There are some foods you should avoid to keep your blood pressure from getting way too high.
  • Talk to your prescriber about what foods to avoid while you're Marplan (isocarboxazid). Some foods, like aged cheese and cured meats, can raise your risk of very high blood pressure that needs medical attention. Get help right away if you have chest pain, a severe headache, confusion, or blurry vision. These can be signs of dangerously high blood pressure.
  • Avoid drinking alcohol and avoid drinking too much caffeine while taking Marplan (isocarboxazid). Alcohol can make you feel sleepier and dizzier. Some drinks, like beer, liquors, and too much caffeine, can raise your risk of very high blood pressure. Talk to your prescriber if you can't fully avoid alcohol or if you need help cutting back on caffeine.
  • Don't drive or do anything that needs your full attention until you know how Marplan (isocarboxazid) affects you. This medication can lower your blood pressure, which can make you feel dizzy or faint. This can lead to accidents if you're not careful.
  • Tell your healthcare team about all the prescription and over-the-counter medications you take. Marplan (isocarboxazid) can interact with many medications, which can be unsafe. Your care team can check that your medications are safe to take together.
  • Don't lower your dose or stop taking Marplan (isocarboxazid) without talking to your prescriber first. Doing this too quickly can cause bothersome withdrawal symptoms. Some include headache, upset stomach, muscle aches, trouble sleeping, and anxiety. Follow your prescriber's instructions to slowly lower your dose over time to stop the medication safely.
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Risks and warnings for Marplan (isocarboxazid)

Marplan (isocarboxazid) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Suicidal thoughts or behavior

  • Risk factors: People 24 years or younger | History of depression or other mood problems

Black Box WarningPeople taking Marplan (isocarboxazid) might notice their depression getting worse. Some might also have changes in behavior or thoughts of suicide or self-harm. The risk is highest for people who are 24 years or younger.

blank warning iconWatch for signs like worse depression, anxiety, anger, and restlessness, especially during the first few weeks of taking Marplan (isocarboxazid) or after a dose change. If you or someone else notices these changes, tell your prescriber. Call 911 right away if you have any thoughts of suicide.

Not for use alone in bipolar disorder

Depression can be the first sign of bipolar disorder. Taking antidepressants like Marplan (isocarboxazid) alone can sometimes cause a manic episode in people at risk for bipolar disorder.

Before you start Marplan (isocarboxazid), your prescriber will check if you have or are at risk of bipolar disorder. Marplan (isocarboxazid) isn't used to treat bipolar depression.

Tell your prescriber right away if you or your loved ones notice any unusual behavior while taking Marplan (isocarboxazid). Watch for signs of mania, like having racing thoughts, being restless, getting easily distracted, or talking a lot.

Dangerously high blood pressure

  • Risk factors: History of high blood pressure | Eating fermented or smoked foods | Drinking beer and wine | Taking certain medications that can raise blood pressure

Although it's rare, some people can have dangerously high blood pressure while taking Marplan (isocarboxazid). The risk is higher if you eat foods with a lot of tyramine during treatment. Examples include aged cheese, cured or smoked meats, and pickled or fermented food. Talk to your healthcare team about which foods and drinks to avoid.

Taking certain medications with Marplan (isocarboxazid) can also raise your risk of very high blood pressure. Be sure to tell your healthcare team about all the medications you take. They can help keep you safe by adjusting your treatment, if needed.

Tell your prescriber if you check your blood pressure and it stays higher than usual. Extremely high blood pressure is a medical emergency. Stop taking Marplan (isocarboxazid) and call 911 right away if you have severe headaches, chest pain, fast heartbeat, confusion, or blurry vision. These can be signs of dangerously high blood pressure.

Use with caution in people with seizures

  • Risk factors: History of seizures

Talk to your prescriber if you've had seizures before and if you take medications to control them. Though it's rare, Marplan (isocarboxazid) can make seizures more likely. Your prescriber might need to adjust any seizure medications you take to help keep seizures under control.

Possible liver damage

It's rare, but Marplan (isocarboxazid) might hurt your liver. Your prescriber might have you do occasional blood tests to check your liver while you're taking this medication. Stop taking Marplan (isocarboxazid) and tell your prescriber if your skin or eyes turn yellowish. This could be a sign of liver damage.

Serotonin syndrome

  • Risk factors: Taking more than one antidepressant | Taking other medications that can affect serotonin

Taking Marplan (isocarboxazid) with other medications that raise your serotonin levels can raise your risk of a rare but serious problem called serotonin syndrome. Tell your healthcare team about all your medications, especially antidepressants and mental health medications. Your care team will check to make sure it's safe to take them together.

Get medical help right away if you have a fast heartbeat, sweating, stiff or twitching muscles, fever, and confusion. These could be signs of serotonin syndrome.

Possible effect on certain other conditions

Tell your healthcare team about all the health conditions you have. MAOIs like Marplan (isocarboxazid) can raise the risk of problems related to certain conditions you have. These include kidney problems, diabetes, hyperthyroidism (overactive thyroid), anxiety, agitation, or schizophrenia.

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Marplan (isocarboxazid) dosage

The average cost for 120 tablets of 10mg of Marplan (isocarboxazid) is $577.33 with a free GoodRx coupon. This is 14.68% off the average retail price of $676.65.
tabletTablet
DosageQuantityPrice as low asPrice per unit
10mg120 tablets$577.33$4.81

Typical dosage for Marplan (isocarboxazid)

The typical starting dose is 10 mg by mouth twice a day.

Your prescriber will slowly raise your dose based on how well it works for your depression and if you have side effects. Your daily dose is usually split into 2 to 4 smaller doses taken throughout the day.

The maximum dose is 60 mg per day.

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Interactions between Marplan (isocarboxazid) and other drugs

Marplan (isocarboxazid) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Marplan (isocarboxazid). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

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How much does Marplan (isocarboxazid) cost?

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Marplan (isocarboxazid) contraindications

Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Marplan (isocarboxazid) will not be safe for you to take.

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What are alternatives to Marplan (isocarboxazid)?

There are a number of medications that your doctor can prescribe in place of Marplan (isocarboxazid). Compare a few possible alternatives below.
Marplan (isocarboxazid)
Used for:
$577.33Lowest GoodRx priceView prices
Used for:
$43.35Lowest GoodRx priceView prices
Used for:
  • Depression when other medications haven't worked
$41.97Lowest GoodRx priceView prices
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News about Marplan (isocarboxazid)

References

Best studies we found

American Heart Association. (2024). When to call 911 about high blood pressure.

Drugs and Lactation Database (LactMed®). (2018). Isocarboxazid. National Institute of Child Health and Human Development.

Reeves, R. R., et al. (2010). Antidepressant-induced suicidality: An update. Central Nervous System Neuroscience & Therapeutics.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.