Marplan (Isocarboxazid): Uses, Side Effects, Warnings, & More

What Is Marplan (Isocarboxazid)?

Marplan, generic name Isocarboxazid, is an antidepressant used to treat symptoms of depression. It belongs to a class of medications called monoamine oxidase inhibitors (MAOIs) which work by increasing the levels of certain chemicals in the brain. Due to potentially serious side effects, this medication is not typically given until other antidepressants have been tried.

Marplan is a medication that can be used in adults as well as children and adolescents, but data for the two latter populations is not well established and requires a doctor to weigh its benefits and risks.^{1, 2, 3}

How Does Isocarboxazid Work?

It is not fully understood how Marplan works on the body, but it is thought to prevent the body from breaking down chemicals in the brain by blocking the enzymes that get rid of them. These chemicals are then used to regulate bodily functions like our mood, which may improve depression symptoms.^{1, 2}

What Is Isocarboxazid Used to Treat?

Marplan is a medication FDA-approved for the treatment of depression. A medication is FDA-approved when it has gone through extensive research, and the FDA has recognized that it is both safe and effective for its given indication. Marplan is not recommended for use in patients under 16 years of age due to safety and effectiveness in pediatric populations not being demonstrated. If you wish to use Marplan for children with depression and adolescents with depression, then speak with a doctor.²

Isocarboxazid Warnings & Precautions

Marplan has warnings and precautions associated with the medication. These are warnings that a patient should discuss with their doctor, especially if they have conditions or medications that may be affected by Marplan. Medical attention may be necessary to address these side effects should a person experience them. It should be noted that a person is not guaranteed to experience these problems listed in the warnings should they take Marplan.

Precautions for taking isocarboxazid include:

• Use during pregnancy and breastfeeding: It is unknown if Marplan can cause embryo/fetal harm when administered to a pregnant woman or the levels of excretion into human milk during nursing. Marplan should be used in women who are pregnant or nursing only if clearly needed.
• Worsening of depression/suicidality: It is encouraged for families and caregivers to observe for any signs of new or worsening symptoms. There may be a delay in the medication working, and some patients fail to respond to therapy.
• Use in pediatric populations: The safety and efficacy of Marplan in the pediatric population have not been established. Use of Marplan in children or adolescents should be done after reviewing the risks and benefits.
• Lower seizure threshold: Marplan may potentially lower the threshold for a seizure to occur, so precautions should be taken if epileptic patients are treated.
• Blood pressure: Low blood pressure has been observed in people who take Marplan. This effect can vary depending on other medications present.

Interactions With Isocarboxazid

All medications have possible harmful interactions that can occur when taken in combination with other medications, substances, or herbs. Marplan’s interactions typically have to do with increasing the actions of other medications, leading to an increased risk of dangerous effects. This medication can interact with many medications meant to control your mood and mental health. If you are starting Marplan, discuss the substances you take with your doctor and pharmacist to prevent serious reactions from occurring.

9 substances you should avoid while taking isocarboxazid include:^{1, 2}

• Tricyclic antidepressants (TCAs): Combining TCAs with Marplan can increase the risk of serotonin syndrome, leading to a potentially life-threatening reaction.
• Wellbutrin (bupropion): Wellbutrin is not to be combined with Marplan as it may cause a patient’s blood pressure to rise to dangerous levels.
• Selective serotonin reuptake inhibitors (SSRIs): Using Marplan and SSRIs together is not recommended. Combining these two medications may increase the risk of Serotonin Syndrome.
• Buspar (buspirone): Avoid combining Buspar with Marplan. Together, they may increase the risk of elevated blood pressure.
• Amphetamines: Dangerously high blood pressure can occur from the combination of these medications.
• Dextromethorphan: This substance can be found in many over-the-counter cold products. It should be avoided in combination with Marplan due to reports of brief episodes of psychosis or bizarre behavior.
• Central nervous system (CNS) depressants: Substances, like alcohol and opioids, can suppress the central nervous system, which may interact with Marplan and increase the risk of decreased breathing, and low blood pressure. Some opioids with Marplan can cause Serotonin Syndrome.
• Caffeine: Excessive use of caffeine should be avoided. Combined with Marplan, it may cause dangerously high blood pressure.
• Antihypertensives (blood pressure agents): Marplan may increase the lower blood pressure effects of some medications. This may lead to issues like orthostatic hypotension.

What Foods Should I Avoid With Isocarboxazid?

Marplan can interact with more than medications, it can also interact with certain foods. Foods high in Tyramine, a natural compound in foods, can interact with Marplan and cause a blood pressure crisis where a patient’s blood pressure can become dangerously high. In general, patients should avoid foods that use aging to increase flavor. If your diet consists of food with high tyramine content, discuss with your doctor if Marplan is right for you.²

• Cheese (particularly strong or aged varieties)
• Cured meat
• Soybeans and soybean products
• Dried or over-ripened fruits
• Chocolate
• Alcoholic beverages
• Pickled or fermented foods
• Meats prepared with tenderizers
• Yeast extracts
• Yogurt
• Sour cream

Side Effects of Isocarboxazid

All medications have a potential for side effects. It is not guaranteed that a person will experience side effects associated with Marplan. Most will experience temporary effects that go away with consistent usage of the medication as the body adjusts to it, but sometimes side effects may be prolonged or get worse, which may require medical care. Side effects a person might experience while taking Marplan would be headaches, dizziness, insomnia, and drowsiness.

Common Side Effects of Isocarboxazid

Common side effects with Marplan are associated with symptoms of low blood pressure and feeling dizzy. When blood pressure is low, becoming dizzy or light-headed can be a symptom. These side effects are typically seen within the first week of taking the medication but should get better with consistent medication usage. If these symptoms impact your ability to go about your daily life or get worse, then contact your doctor.

Common side effects of isocarboxazid include:*^{1, 2}

• Headache
• Dizziness
• Insomnia
• Dry mouth
• Low blood pressure
• Feeling faint/lightheaded
• Nausea

This is not a complete list of possible side effects with Marplan. You should talk with your healthcare prescriber about the potential risks of Marplan before starting the medication.

Serious Side Effects of Isocarboxazid

Serious side effects that occur with Marplan involve how it works in the body. If too many naturally occurring chemicals, like serotonin, build up in the body, then it can cause adverse effects. These side effects could be potentially serious and even life-threatening. Marplan could potentially cause Serotonin Syndrome, especially in combination with other medications, as well as hypertensive crisis. A person who experiences these side effects needs to seek immediate care.

Serious side effects of isocarboxazid may include:*^{1, 2}

• Fast or pounding heartbeat
• Neck stiffness
• Fever
• Fainting
• Tightness in the throat or chest

*All medications, including isocarboxazid, can cause side effects which can be mild or serious. This is not a comprehensive list of all possible side effects. You should talk with your doctor about any questions you have and to understand the potential side effects and benefits of any medication.

Antidepressant Discontinuation

Antidepressant discontinuation syndrome, also known as antidepressant withdrawal is a condition that can occur when antidepressants are interrupted, reduced in dosage, or stopped. Some symptoms a person can experience are flu-like symptoms, trouble sleeping, nausea, poor balance, and sensory changes. Medical intervention may be needed if you develop this condition.⁴

Allergic Reactions to Isocarboxazid

As with all medications, some may be allergic to Marplan. If a person has an allergy to Marplan or any of its ingredients, they should avoid using the medication. Allergic reactions can be a serious medical event. If you or a person you know experience an allergic reaction, seek appropriate medical care. Those allergic to Marplan may be allergic to any of the components within the medication or even the active drug itself.

Allergic reactions to isocarboxazid may include:⁵

• Difficulty breathing
• Wheezing and coughing
• Fast heart rate
• Itching
• Abnormally low blood pressure
• Hives
• Swelling of lips, face, or throat

If you experience any of these symptoms, seek immediate medical care. This can be a life-threatening event which may require medical intervention. A reaction to Marplan means that you will have to be taken off this medication and placed on a new medication to manage your symptoms. Potential medication classes you could consider for your depression would be other MAOIs, SSRIs, and SNRIs. What medication you may be prescribed is dependent on individual factors.

Isocarboxazid Dosages for FDA-Approved Treatment

Marplan is FDA-approved for depression, where the patient is started on 10 mg twice daily. This dosage is increased by 10 mg every 2 to 4 days until a dosage of 40 mg is reached by the end of the first week. If needed, the dosage can go up to a maximum of 60 mg.

Dosages can vary for each individual on Marplan depending on their personal factors. The dosage that a person needs for treatment depends on several factors. A patient’s current medications, conditions, and individual response to the medication can affect what dosage is needed for treatment.^{1, 2}

Isocarboxazid Forms & Strengths

There is only one strength and form of Marplan available, and it comes as a 10 mg oral immediate-release tablet. This oral tablet is usually taken whole, but it can be crushed if a person is unable to swallow whole tablets.³ If a tablet is crushed, be sure to take the entire entire dose immediately. Patients may see their mood improve within the week, but it may take up to 6 weeks to see the full benefits of Marplan.^{1, 2}

Marplan is available in the following forms and strengths:

• 10 milligrams (mg) oral tablet

Always take medications as prescribed, and never take less or more of a medication without medical supervision, as this may make the therapy ineffective or cause unintended side effects. Marplan should be taken by mouth with or without food.

How Should I Take Isocarboxazid?

Marplan should be taken by mouth around the same time every day. When first starting Marplan, your dosage may occasionally change to get you to the dosage you need for the most benefit.^{1, 2} Marplan can be taken with or without food, but be sure to avoid foods high in tyramine to avoid a drug interaction.³ It is important to take Marplan as prescribed to minimize the risk of adverse side effects or an overdose. Do not take less or more of this medication than recommended.

What Should I Do If I Miss a Dose of Isocarboxazid?

If you miss a dose of Marplan, take the missing dose as soon as you remember. If you are close to your next dose, then take that one as scheduled and skip the missed dose. Do not take extra medication to make up for any mixed doses. It is important not to abruptly stop Marplan as this can lead to symptoms associated with the withdrawal of antidepressants.²

Can You Overdose on Isocarboxazid?

There is a potential for someone to overdose on Marplan. Signs and symptoms of an overdose may include low blood pressure, fast heart rate, coma, seizures, slow or shallow breathing, sluggish reflexes, fever, and sweating. These symptoms may persist for 8 to 14 days. To decrease the risk of an overdose, ask your doctor or pharmacist when starting new medications or substances, and take Marplan only as prescribed.^{1, 2}

What Should You Do If You Take Too Much Isocarboxazid?

If you have taken more Marplan than prescribed, seek immediate medical advice. If you are not displaying symptoms, contact the Poison Control Center (1-800-222-1222) for advice and follow medical instructions as given. If you display any symptoms, overdose or otherwise, then call 911 and seek immediate medical attention to receive treatment to prevent any serious complications from occurring.

Questions to Ask Your Healthcare Provider About Marplan (Isocarboxazid)

If you are considering taking Marplan, you should meet your doctor with a list of questions to ask. Questions you should ask your doctor or psychiatrist are the expectations once you start taking this medication, the side effects associated with Marplan, and how Marplan works in your overall therapy. If you have trouble meeting with a doctor in person, online psychiatry services may be a good option if you need to change prescribers.

Questions to ask your care team about isocarboxazid include:

• How long will it take for me to adjust to taking isocarboxazid?
• Am I at risk for more severe symptoms if I am already taking other anxiety /depression medications?
• What is the best dosage to ensure fewer side effects?
• When should I reach out to you if I am experiencing sexual side effects?
• Is there anything I should tell my therapist about this new medication?
• How long does it take for me to see a result?
• How long should I try this medication before deciding it is not for me?
• Can I take Marplan with other mental health medications?

In My Experience

In my experience, Marplan is not a drug that many people use. As stated before, Marplan is not typically the first choice when treating someone for depression, as there are many side effects and interactions to be aware of. Marplan was typically reserved for those who did not respond well to the first-line treatments for depression.

This medication can be an effective treatment, but the many interactions can be a factor that some may find bothersome, as they have to be careful when starting new medications or eating certain foods. Patients should also be aware that it may take a few weeks for a patient to see the full benefits of Marplan, and if they do not see benefits or the side effects are bothersome, then they should contact their doctor.