provider image
Welcome! You’re in GoodRx for healthcare professionals. Now, you’ll enjoy a streamlined experience created specifically for healthcare professionals.
Skip to main content

Marplan

isocarboxazid
Used for Depression
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:
reviewer
Robert Chad Hakim, PharmD, BCCCP
reviewer
Cydnee Ng, PharmD
Last reviewed on April 21, 2025
BasicsSide effectsPros & consPharmacist tipsFAQsWarningsDosageInteractionsCostContraindicationsAlternativesLatest newsPricesMedicare
basics-icon

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.

Are you looking for information on isoniazid instead?
When does Marplan (isocarboxazid) start working?
Time passed since treatment started:
HOURS
DAYS
WEEKS
MONTHS
Full effect

Drug Facts

Common BrandsMarplan
Drug ClassMAOI
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
coupon-save-icon

Get your GoodRx coupon

Avg retail price
$691.23(save 14.38%)
GoodRx discount
$591.86
See prices
basics-icon

What are the 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%)

Other Side Effects

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 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:

More common

Constipation

dry mouth

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.

pros-and-cons

Pros and cons of Marplan (isocarboxazid)

thumbs-up

Pros

Possible option for depression when other antidepressants haven't worked well

Taken by mouth

Can take with or without food

thumbs-down

Cons

Not a first-choice option because it can have serious side effects

Can interact with other medications and foods

Taken multiple times in a day

pharmacist-tips

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.

                More on Marplan (isocarboxazid) tips

                MAOI: Diet: holding phone pushing grocery cart 926538832

                7 Foods to Consider Avoiding If You’re Taking an MAOI

                Written by Amy B. Gragnolati, PharmD, BCPS
                Mental health: Self-harm: young woman distress 1272795673

                How Long Does It Take for Antidepressants to Work?

                Written by Tegan Smedley, PharmD, APh
                faqs

                Frequently asked questions about Marplan (isocarboxazid)

                Is Marplan (isocarboxazid) still available?
                Marplan (isocarboxazid) is still available according to the manufacturer. Ask your pharmacist or prescriber if you have any questions about availability.
                Is Marplan (isocarboxazid) an MAOI?
                Yes, Marplan (isocarboxazid) is a monoamine oxidase inhibitor (MAOI) that's used to treat depression. It works by stopping MAO proteins from working. This raises the levels of certain chemicals in the brain that help regulate mood. MAOIs like Marplan (isocarboxazid) aren't usually the first choice for depression. This is because they have a lot of side effects, drug interactions, and dietary restrictions.
                How long does Marplan (isocarboxazid) take to work?
                Marplan (isocarboxazid) can take some time to start working. Some people might feel a little better within a week or two. But it usually takes 3 to 6 weeks or more to see the full effect of the medication on your mood. Try to be patient and keep taking Marplan (isocarboxazid) every day, even if you don't feel a difference right away. Ask your prescriber if you have questions about how long it might take to feel better.
                What foods should you avoid while taking Marplan (isocarboxazid)?
                You should avoid foods high in tyramine while taking Marplan (isocarboxazid). These include aged cheese; yogurt; cured meats; soy sauce; and smoked, pickled, or fermented food. These foods have a natural substance called tyramine. When you take this medication, your body can't break down tyramine. Too much tyramine can cause your blood pressure to go up too much. This dangerous rise in blood pressure is called hypertensive crisis. It's serious and can lead to symptoms like severe headache, vision changes, and trouble breathing. Talk to your care team if you have a hard time avoiding these types of foods. They might switch you to a different medication.
                Can you take Marplan (isocarboxazid) for anxiety?
                Your prescriber might consider an MAOI like Marplan (isocarboxazid) for anxiety. But it's not a first-choice option and it's not FDA approved for anxiety. Also keep in mind that anxiety can be a side effect of Marplan (isocarboxazid). If you have depression and anxiety, talk to your prescriber about your treatment options.
                Can you take Marplan (isocarboxazid) while pregnant?
                MAOIs like Marplan (isocarboxazid) aren't recommended during pregnancy. It's not known how safe they are for pregnant people and their baby. If you become pregnant or are planning to become pregnant while taking this medication, tell your prescriber. They can talk to you about other options. If you become pregnant while taking Marplan (isocarboxazid), it's a good idea to join the National Pregnancy Registry for Psychiatric Medications. This helps researchers learn more about the medication's effects during pregnancy. You can join by calling 1-844-405-6185 or visiting their website.
                Can you breastfeed while taking Marplan (isocarboxazid)?
                It's recommended to avoid breastfeeding while taking Marplan (isocarboxazid). We don't know much about how the medication affects your baby or your milk supply. Ask your care team about options other than breastfeeding like using formula. If you want to breastfeed, ask if there's a different antidepressants that might be safer.
                GoodRxEducationalIcon

                How to save using GoodRx

                Compare Prices
                1. Compare PricesSpecify your dosage and quantity to find out exactly how much you can save.
                Select your free coupon
                2. Select your free couponYou can use the displayed coupon, or compare prices at other pharmacies near you.
                Show coupon to your pharmacist
                3. Show coupon to your pharmacistPresent your printed or electronic coupon when you pick up your prescription.
                Get free couponLearn more
                warings-icon

                What are the 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.

                risk-warning

                Suicidal thoughts or behavior

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

                  People 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.

                  Watch 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.

                  risk-warning

                  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.

                  risk-warning

                  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.

                    risk-warning

                    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.

                      risk-warning

                      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.

                      risk-warning

                      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.

                        risk-warning

                        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.

                        dosage

                        Marplan (isocarboxazid) dosage forms

                        The average cost for 120 tablets of 10mg of Marplan (isocarboxazid) is $591.86 with a free GoodRx coupon. This is 14.38% off the average retail price of $691.23.
                        tablet
                        Tablet
                        DosageQuantityPrice as low asPrice per unit
                        10mg120 tablets$591.86$4.93

                        Typical dosing 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.

                        interactions

                        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.

                        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.

                        drug-cost

                        How much does Marplan (isocarboxazid) cost?

                        To access savings, use a GoodRx coupon and pay just a fraction of the retail price.
                        Marplan (brand)
                        GoodRx lowest price

                        $591.86

                        (save 14.38%)
                        View prices & coupons
                        contraindications-icon

                        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.
                        alternatives

                        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:
                        $591.86 Lowest GoodRx priceView Prices
                        Tranylcypromine (Parnate)
                        Used for:

                        • Depression when other medications haven't worked

                        $80.42 Lowest GoodRx priceView Prices
                        Phenelzine (Nardil)
                        Used for:
                        $40.86 Lowest GoodRx priceView Prices
                        latest news

                        What is the latest news about Marplan (isocarboxazid)?

                        Has a loved one’s struggle with depression left you unsure of how to support them? Learn about depression and the ways you can help.

                        How to Help Someone With Depression

                        Has a loved one’s struggle with depression left you unsure of how to support them? Learn about depression and the ways you can help.
                        While taking MAOIs, it’s important to follow a low-tyramine diet and restrict foods, such as aged meats and cheeses, to avoid dangerously high blood pressure.

                        7 Foods to Consider Avoiding If You’re Taking an MAOI

                        While taking MAOIs, it’s important to follow a low-tyramine diet and restrict foods, such as aged meats and cheeses, to avoid dangerously high blood pressure.
                        Serotonin syndrome is a reaction to commonly prescribed medications and supplements. Learn what serotonin syndrome is, what causes it, how to treat it, and more.

                        Serotonin Syndrome: What You Need to Know If You Take SSRIs

                        Serotonin syndrome is a reaction to commonly prescribed medications and supplements. Learn what serotonin syndrome is, what causes it, how to treat it, and more.
                        Zoloft is a popular antidepressant, but it's important to be aware of its potential side effects. Here's what side effects to expect during your first week and beyond.

                        Zoloft for Depression: Important Things to Know Before Taking This Antidepressant

                        Zoloft is a popular antidepressant, but it's important to be aware of its potential side effects. Here's what side effects to expect during your first week and beyond.
                        Antidepressant discontinuation syndrome (antidepressant withdrawal) occurs when you quickly stop or lower the dose of your antidepressant. Here’s why it happens and how you can avoid it.

                        What Is Antidepressant Discontinuation Syndrome? Withdrawal from Antidepressants Explained

                        Antidepressant discontinuation syndrome (antidepressant withdrawal) occurs when you quickly stop or lower the dose of your antidepressant. Here’s why it happens and how you can avoid it.
                        Treating anxiety is the first step to living well. Find out how you can get anxiety medication from your provider and what you need to know about treatment.

                        Getting Anxiety Medication: 9 Things to Know When Starting Treatment

                        Treating anxiety is the first step to living well. Find out how you can get anxiety medication from your provider and what you need to know about treatment.
                        Manufacturers raised the cost of 619 medications in January as part of a yearly tradition of price hikes. Drugs that went up in price include some of the most expensive medications in the U.S., such as Myalept and Juxtapid. These higher prices will likely to trickle down to all consumers (insurance or not) through higher costs at the pharmacy and higher out-of-pocket costs.

                        Over 600 Drugs Saw Price Hikes in January – What Does It Mean for Consumers?

                        Manufacturers raised the cost of 619 medications in January as part of a yearly tradition of price hikes. Drugs that went up in price include some of the most expensive medications in the U.S., such as Myalept and Juxtapid. These higher prices will likely to trickle down to all consumers (insurance or not) through higher costs at the pharmacy and higher out-of-pocket costs.

                        Get savings updates for Marplan (isocarboxazid)

                        Receive price alerts, news, and other messages from GoodRx about Marplan (isocarboxazid) and other healthcare topics and relevant savings offers.

                        By signing up, I agree to GoodRx's Terms and Privacy Policy, and to receive marketing messages from GoodRx.

                        Browse medications

                        View All

                        Research prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.