1. Mirtazapine oral tablets are available as brand-name drugs and generic drugs. Brand names: Remeron (immediate-release tablet), Remeron Soltab (orally disintegrating tablet).
  2. Mirtazapine comes as an immediate-release tablet you take by mouth. It also comes as a tablet that dissolves in your mouth.
  3. Mirtazapine is used to treat depression.

FDA warning: Suicide risk

  • This drug has a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous.
  • Mirtazapine may cause an increase in suicidal thoughts or actions. This risk is higher in children, teenagers, and young adults. It’s also higher within the first few months of treatment and during dosage changes. You and your family members, caregivers, and doctor should watch for any new or sudden changes in your mood, behaviors, thoughts, or feelings. Call your doctor right away if you notice any of these changes.

Other warnings

  • Serotonin syndrome warning: Mirtazapine can cause a life-threatening condition called serotonin syndrome. Your risk may be higher if you also take other drugs that have similar effects as mirtazapine. These include antidepressants or triptans, such as sumatriptan and zolmitriptan. Symptoms of serotonin syndrome include agitation, hallucinations (seeing or hearing something that isn’t there), confusion, trouble thinking, coma, coordination problems, and muscle twitching. They also include stiff muscles, racing heartbeat, high or low blood pressure, sweating, fever, nausea, vomiting, and diarrhea. Call your doctor right away if you have these symptoms.
  • Withdrawal warning: Don’t stop taking mirtazapine without talking to your doctor. Stopping it suddenly can cause withdrawal symptoms. These include anxiety, agitation, shaking, and tingling or electric shock-like feelings. They also include sweating, nausea, vomiting, strange dreams, dizziness, tiredness, confusion, and headache. If you need to stop taking this drug, your doctor will slowly reduce your dosage over time. Your doctor will watch you for withdrawal symptoms when stopping treatment.
  • Drowsiness warning: This drug can cause drowsiness. It may also affect your ability to make decisions, think clearly, or react quickly. You shouldn’t drive, use machinery, or do other activities that require alertness until you know how this drug affects you.

Mirtazapine is a prescription drug. It comes as an oral immediate-release tablet or an orally disintegrating (dissolving) tablet.

Mirtazapine is available as the brand-name drugs Remeron (immediate-release tablet) and Remeron Soltab (orally disintegrating tablet). Both forms are also available as generic drugs. Generic drugs usually cost less than brand-name versions. In some cases, they may not be available in every strength or form as brand-name drugs.

Mirtazapine may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

Mirtazapine is used to treat depression.

Mirtazapine belongs to a class of drugs called antidepressants. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

It isn’t known exactly how mirtazapine works to treat depression. It may increase the amounts of norepinephrine and serotonin in your brain. These are chemical messengers that affect your mood.

Mirtazapine oral tablet may cause drowsiness. It may affect your ability to make decisions, think clearly, or react quickly. You shouldn’t drive, use machinery, or do other activities that require alertness until you know how this drug affects you.

You may feel restless and agitated (unable to sit or stand still) for the first few weeks while taking this drug.

Mirtazapine can also cause other side effects.

More common side effects

The more common side effects of mirtazapine can include:

  • sleepiness
  • increased appetite
  • weight gain
  • dry mouth
  • constipation
  • dizziness
  • strange dreams

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Suicidal thoughts or actions. Symptoms can include:
    • attempts to commit suicide
    • acting on dangerous impulses
    • acting aggressive or violent
    • thoughts about suicide or dying
    • new or worsened depression
    • new or worsened anxiety or panic attacks
    • feeling agitated, restless, angry, or irritable
    • trouble sleeping
    • an increase in activity or talking more than normal
    • other unusual changes in behavior or mood
  • Manic episodes. Symptoms can include:
    • greatly increased energy
    • severe trouble sleeping
    • racing thoughts
    • reckless behavior
    • unusually grand ideas
    • excessive happiness or irritability
    • talking more or faster than normal
  • Weakened immune system. Mirtazapine may decrease your white blood cells. White blood cells help your body fight infections. This can make you more likely to get infections. Symptoms can include:
    • fever
    • chills
    • sore throat
    • mouth or nose sores
    • flu-like symptoms, such as body aches, fatigue, and vomiting
  • Serotonin syndrome. This condition can be life-threatening. Symptoms can include:
    • agitation
    • hallucinations (seeing or hearing something that isn’t there)
    • coma
    • confusion
    • trouble thinking
    • coordination problems
    • muscle twitching or stiff muscles
    • racing heartbeat
    • high or low blood pressure
    • sweating or fever
    • nausea, vomiting, or diarrhea
  • Eye problems. Symptoms can include:
    • eye pain
    • changes in vision
    • swelling or redness in or around your eye
  • Seizures
  • Low sodium (salt) levels in your blood. Seniors may be at a higher risk for this problem. Symptoms can include:
    • headache
    • feeling unsteady or weak
    • confusion, trouble concentrating or thinking, or memory problems
  • Sleepiness
  • Severe skin reactions. Symptoms can include:
    • severe rash with skin swelling (including on the palms of your hands and soles of your feet)
    • painful reddening of your skin or blisters or ulcers (open sores) on your body or in your mouth
  • Severe allergic reactions. Symptoms can include:
    • trouble breathing
    • swelling of your face, tongue, eyes, or mouth
    • Hives can be seen in allergic reactions to mirtazapine.

    • rash, itchy welts (hives), or blisters, alone or with fever or joint pain
  • Increased appetite or weight
  • High cholesterol and triglyceride levels
  • Rhabdomyolysis (a serious muscle problem). Symptoms can include:
    • muscle aches and pains
    • kidney problems

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Mirtazapine oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with mirtazapine are listed below.

Drugs you shouldn’t take

Taking certain drugs with mirtazapine may cause serious side effects. You shouldn’t take these medications while taking mirtazapine.These drugs include:

  • Monoamine oxidase inhibitors (MAOIs), such as isocarboxazid, phenelzine, and tranylcypromine. Taking these drugs with mirtazapine can increase your risk of serotonin syndrome. If you need to take an MAOI, you must wait 14 days after you stop taking mirtazapine before you start taking the MAOI. The same rule applies if you switch from taking an MAOI to mirtazapine. If you’re switching from one of these drugs to the other, seek medical help right away if you have symptoms of serotonin syndrome.
  • Linezolid and intravenous methylene blue. Taking these drugs with mirtazapine can increase your risk of serotonin syndrome.

Drugs that cause more side effects

Taking mirtazapine with certain medications may cause more side effects. These drugs include:

  • Benzodiazepines, such as diazepam, triazolam, and midazolam. You may have more sedation and drowsiness.
  • Triptans, such as sumatriptan. Ask your doctor whether it’s safe for you to take these drugs together. Taking these medications with mirtazapine may increase your risk of serotonin syndrome. Your doctor should watch you closely when you start taking these drugs together and during dosage changes.
  • Lithium. Ask your doctor whether it’s safe for you to take these drugs together. Taking lithium with mirtazapine may increase your risk of serotonin syndrome.
  • Serotonergic medications, such as fentanyl, tramadol, and St. John’s wort. Ask your doctor whether it’s safe for you to take these drugs together. Taking these medications with mirtazapine may increase your risk of serotonin syndrome.
  • Drugs that affect your heart rhythm, such as some antipsychotics and antibiotics. Ask your doctor whether it’s safe for you to take these drugs together. Taking these medications with mirtazapine may increase your risk of a heart rhythm problem called QT prolongation.
  • Warfarin. You may have an increase in bleeding. Your doctor will watch you closely if you take these drugs together.
  • Drugs that increase the amount of mirtazapine in your body

    These drugs can increase the levels of mirtazapine in your body. This may cause more side effects. If you need to take these drugs with mirtazapine, your doctor may decrease your mirtazapine dosage.

    • Cimetidine
    • Antifungals, such as ketoconazole
    • Antibiotics, such as erythromycin
    • Protease inhibitors for human immunodeficiency virus (HIV), such as ritonavir

    Drugs that reduce the amount of mirtazapine in your body

    These drugs can reduce the levels of mirtazapine in your body. If you need to take these drugs with mirtazapine, your doctor may increase your mirtazapine dosage.

    • Phenytoin
    • Carbamazepine

    Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

This drug comes with several warnings.

Allergy warning

Mirtazapine can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your face, tongue, eyes, or mouth
  • severe rash with skin swelling, including on the palms of your hands and soles of your feet
  • painful reddening of your skin or blisters or ulcers (open sores) on your body or in your mouth
  • itchy welts (hives) or blisters, alone or with a fever or joint pain

If you develop these symptoms, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Alcohol interaction warning

The use of drinks that contain alcohol can increase your risk of sleepiness from mirtazapine. This may affect your ability to make decisions, think clearly, or react quickly. If possible, you should avoid alcohol while you’re taking this drug. If you drink alcohol, talk to your doctor.

Warnings for people with certain health conditions

For people with a history of mania or bipolar disorder: Talk to your doctor about whether this drug is safe for you. Mirtazapine may trigger a mixed or manic episode.

For people with seizures: Talk to your doctor about whether this drug is safe for you. This drug may make your condition worse. If you have a seizure while taking mirtazapine, talk to your doctor. They will decide if you should stop taking it. You may need to stop taking this drug right away, or your dosage may slowly be lowered over time to avoid withdrawal symptoms.

For people with heart problems: If you have a history of certain heart problems, talk to your doctor about whether this drug is safe for you. These heart problems include angina (chest pain), heart attack, or stroke. Mirtazapine can cause low blood pressure, which can make heart problems worse.

For people with glaucoma or other eye problems: This drug may dilate your pupils. This may trigger a glaucoma attack. Before you take this drug, tell your doctor if you have glaucoma.

For people with kidney problems: If you have kidney problems or a history of kidney disease, you may not be able to clear this drug from your body well. This may increase the amount of mirtazapine in your body and cause more side effects.

For people with liver problems: If you have liver problems or a history of liver disease, you may not be able to process this drug as well. This may increase the amountof mirtazapine in your body and cause more side effects.

Warnings for other groups

For pregnant women: Mirtazapine is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Call your doctor right away if you’re pregnant or planning to become pregnant. This drug should only be used if the potential benefit justifies the potential risk.

For women who are breastfeeding: Mirtazapine may pass into breast milk and may cause side effects in a child who is breastfed. Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.

For seniors: The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, higher amounts of a drug stay in your body for a longer time. This raises your risk of side effects, such as confusion or drowsiness.

For children: It isn’t known if mirtazapine is safe and effective for children younger than 18 years.

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Drug forms and strengths

Generic: Mirtazapine

  • Form: oral immediate-release tablet
  • Strengths: 7.5 mg, 15 mg, 30 mg, 45 mg
  • Form: orally disintegrating tablet
  • Strengths: 15 mg, 30 mg, 45 mg

Brand: Remeron

  • Form: oral immediate-release tablet
  • Strengths: 15 mg, 30 mg, 45 mg

Brand: Remeron SolTab

  • Form: orally disintegrating tablet
  • Strengths: 15 mg, 30 mg, 45 mg

Dosage for depression

Adult dosage (ages 18–64 years)

  • Typical starting dosage: 15 mg taken once per day, usually in the evening before bedtime.
  • Dosage increases: Your doctor will slowly increase your dosage every 1–2 weeks. They’ll change your dosage based on your depression symptoms.
  • Maximum daily dosage: 45 mg taken once per day.

Child dosage (ages 0–17 years)

It hasn’t been confirmed that this drug is safe and effective for use in people younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, higher amounts of a drug stay in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dosage or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Mirtazapine is used for long-term treatment. It comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug or don’t take it at all: Your depression may get worse. If you suddenly stop taking mirtazapine, you may have withdrawal symptoms. These can include:

  • anxiety
  • agitation
  • shaking
  • tingling or electric shock-like sensations
  • sweating
  • nausea
  • vomiting
  • strange dreams
  • dizziness
  • tiredness
  • confusion
  • headache

If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • confusion
  • sleepiness
  • memory problems
  • fast heart rate

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working: You should have decreased symptoms of depression and be in a better mood. Note that it may take 4 weeks before this drug works to treat your depression.

Keep these considerations in mind if your doctor prescribes mirtazapine for you.

General

  • You can take mirtazapine with or without food.
  • Take mirtazapine close to bedtime because it may cause sleepiness.
  • You can cut or crush the immediate-release tablets.
  • You cannot cut or crush the orally disintegrating tablets.

Storage

  • Store mirtazapine at room temperature between 59°F and 86°F (15°C and 30°C).
  • Keep this drug away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t harm your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

You and your doctor should monitor certain health issues while you take this drug. This can help make sure you stay safe during your treatment. These issues include:

  • Kidney and liver function. Your doctor may do blood tests to check how well your kidneys and liver are working. If your kidneys or liver aren’t working well, your doctor may lower your dosage of this drug.
  • Mental health and behavioral problems. You and your doctor should watch for any unusual changes in your behavior and mood. This drug can cause new mental health and behavior problems. It can also worsen problems you already have.
  • White blood cell counts. This drug can decrease the number of white blood cells in your body. You need white blood cells to fight infections. Your doctor may check your white blood cell count while you’re taking this drug.
  • Cholesterol levels. This drug can increase your cholesterol. Your doctor will check your cholesterol levels while you’re taking this drug.

Availability

Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead to make sure your pharmacy carries it.

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.