Remeron (Mirtazapine) Oral: Uses, Side Effects, Dosages - Verywell Health

What Is Remeron?

Remeron (mirtazapine) is a prescription oral antidepressant drug used to treat major depressive disorder (MDD), or clinical depression. MDD is a mental health disorder that causes persistent, severely depressed mood, loss of interest in activities, and other symptoms like sleep changes.

Remeron works a little differently than any of the other antidepressant drugs currently available on the U.S. market. For that reason, it is sometimes called an "atypical" antidepressant.

Specifically, Remeron is a type of drug called a noradrenergic and specific serotonergic antidepressant. Remeron is also sometimes classified as a tetracyclic antidepressant (a name based on its chemical structure). These drugs work in the central nervous system to strengthen certain chemicals in the brain.

Remeron works mainly on two different types of neurotransmitters, called brain signaling molecules, inside your brain. It increases the amount of norepinephrine that is released and available for brain signaling, as well as serotonin. These neurotransmitters trigger further signals in the brain. Ultimately, scientists think this helps ease the symptoms of depression.

Remeron is available as a tablet and a disintegrating tablet.

Drug Facts

Generic Name: Mirtazapine

Brand Name: Remeron, Remeron Soltab

Drug Availability: Prescription

Therapeutic Classification: Antidepressant

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Mirtazapine

Dosage Form(s): Tablet, disintegrating tablet

What Is Remeron Used For?

The Food and Drug Administration (FDA) has approved Remeron as a treatment for clinical depression in adults.

MDD can cause symptoms including, but not limited to:

• Persistent sadness, anxiousness, or "empty" feeling
• Feelings of hopelessness or pessimism
• Irritability
• Loss of interest or pleasure in hobbies and activities
• Decreased energy or fatigue
• Difficulty sleeping, early-morning awakening, or oversleeping

How to Take Remeron

Since Remeron can make you sleepy, you may want to take it before you go to bed. It can be taken with or without food. Do not break or split the disintegrating tablet; it will dissolve in seconds on your tongue or you can swallow it.

Verywell / Zoe Hansen

Storage

Remeron should be stored at room temperature, away from light and heat. Keep the orally disintegrating tablet in its original package until you are ready to take it.

Off-Label Uses

Healthcare providers sometimes prescribe Remeron for off-label, or unapproved, uses in other medical conditions. This just means that the FDA hasn't done the full set of studies required for official approval for these conditions. Still, some evidence suggests that Remeron may be helpful in these situations.

Some off-label uses include:

Remeron can also be used to help people gain weight in certain situations. For example, this might make sense for someone with advanced cancer. Older adults in nursing homes who have little appetite and are underweight may also benefit. However, it must be used with caution due to the increased risk of sedation and fall risk.

How Long Does Remeron Take to Work?

You may start to see an improvement in your symptoms after a week, but it can take up to several weeks for some people.

What Are the Side Effects of Remeron?

This is not a complete list of side effects, and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at www.fda.gov/medwatch or 1-800-FDA-1088.

Remeron may not cause any side effects in some people. However, some do experience mild problems from the drug. Rarely, Remeron can cause severe side effects.

Common Side Effects

The most common side effects from Remeron are:

• Dry mouth
• Sleepiness
• Increased appetite and weight gain

Severe Side Effects

Very rarely, Remeron may cause serious symptoms. The drug is safe and effective for many people, but it is good to be aware of the potential risks before you start it. If you experience any of these issues, you'll probably need to stop taking the drug. However, consult with your healthcare provider first.

Serotonin Syndrome

Serotonin syndrome is a potentially serious problem that can occur while taking Remeron. It can sometimes happen while taking the medication as recommended; however, it is more likely to occur if someone has overdosed. Taking both Remeron and another drug that can affect the serotonin in the brain increases the risk.

Symptoms of serotonin syndrome can be mild, but sometimes severe symptoms happen, such as:

Worsening Symptoms and Suicide

Although rare, Remeron may actually worsen depressive problems initially. A small percentage of people may experience problems such as thinking more about suicide.

Because of this risk, it's important to carefully monitor anyone who is taking Remeron, especially when a person first starts taking the drug or when they change their dose. It might be a particular risk for younger adults who start the medication. However, it's important to note that untreated depression itself already poses this risk.

If you notice symptoms like worsened mood after starting Remeron, contact your mental health care provider right away. If you are having suicidal thoughts, call 911 or a suicide prevention hotline.

Other Rare, Potentially Serious Problems

Very rarely, mirtazapine might trigger a problem called "agranulocytosis," which means that you have a very low number of certain immune cells (called neutrophils). Agranulocytosis might make you more prone to getting some infections.

Other very rare but potentially serious problems include:

• Severe skin reactions (such as something called Stevens Johnson syndrome) 
• Symptoms from acute angle closure glaucoma (closed-angle glaucoma)
• Seizure
• Low sodium in the blood (hyponatremia)
• Heart rhythm issues

If you notice any problems, like unusual fever, call your healthcare provider. You should also seek immediate treatment if you notice strange eye symptoms, like blurred vision and eye pain. These might be a sign of an eye emergency from glaucoma-like symptoms.

For potentially life-threatening symptoms, like seizure, chest pain, or difficulty breathing, call 911.

Dosage: How Much Remeron Should I Take?

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage forms (orally disintegrating tablets, tablets):
  • For depression:
    • Adults—At first, 15 milligrams (mg) once a day, preferably in the evening just before sleep. Your doctor may adjust your dose if needed. However, the dose is usually not more than 45 mg per day.
    • Children—Use and dose must be determined by your doctor.

Modifications

Except in unusual circumstances (like a severe drug reaction), you should not stop taking Remeron without consulting a healthcare professional.

Stopping Remeron may cause symptoms like:

• Nausea
• Headache
• Agitation
• Fatigue

Instead, work closely with your healthcare provider. You are much less likely to experience symptoms if you stop taking the drug gradually (e.g., using a lowered dose for a while). However, some people don't notice any symptoms when they stop taking Remeron.

Use Remeron with caution if you have:

• Known cardiovascular or cerebrovascular disease
• Conditions that predispose you to hypotension (e.g., dehydration, hypovolemia)
• Moderate to severe kidney or liver impairment

Dosage may also need to be modified in older adults (aged 65 years or older).

Missed Dose

If you miss your Remeron dose, don't panic. Take your pill as soon as you remember. If it is very close to your next dose, just take your next planned dose then. Do not double up.

Overdose: What Happens If I Take Too Much Remeron?

Some signs of Remeron overdose might include sleepiness, disorientation, and rapid heartbeat.

What Happens If I Overdose on Remeron?

If you think you or someone else may have overdosed on Remeron (mirtazapine), call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking mirtazapine, call 911 immediately.

Precautions

It is very important that your doctor check your progress at regular visits, to allow changes in your dose and help reduce any side effects. Blood tests may be needed to check for unwanted effects.

Do not take mirtazapine with a monoamine oxidase (MAO) inhibitor (eg, isocarboxazid [Marplan®], linezolid [Zyvox®], methylene blue injection, phenelzine [Nardil®], selegiline [Eldepryl®], tranylcypromine [Parnate®]). Do not start taking mirtazapine during the 2 weeks after you stop a MAO inhibitor and wait 2 weeks after stopping mirtazapine before you start taking a MAO inhibitor. If you take them together or do not wait 2 weeks, you may develop confusion, agitation, restlessness, stomach or intestinal symptoms, a sudden high body temperature, an extremely high blood pressure, or severe seizures.

Mirtazapine may cause a serious condition called serotonin syndrome if taken together with some medicines. Do not use mirtazapine with buspirone (Buspar®), fentanyl (Abstral®, Duragesic®), lithium (Eskalith®, Lithobid®), tryptophan, St. John's wort, or some pain or migraine medicines (eg, rizatriptan, sumatriptan, tramadol, Frova®, Imitrex®, Maxalt®, Relpax®, Ultram®, Zomig®). Check with your doctor first before taking any other medicines with mirtazapine. Check with your doctor right away if you are having agitation, difficulty in breathing, a fast heartbeat, hallucinations, a high fever, high or low blood pressure, increased sweating, loss of bladder control, seizures, severe muscle stiffness, unusually pale skin, or tiredness while you are taking this medicine.

Mirtazapine may cause some teenagers and young adults to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Some people may have trouble sleeping, get upset easily, have a big increase in energy, or start to act reckless. If you or your caregiver notice any of these unwanted effects, tell your doctor right away. Let the doctor know if you or anyone in your family has bipolar disorder (manic-depressive) or has tried to commit suicide..

This medicine may add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are taking this medicine.

This medicine can temporarily lower the number of white blood cells in your blood, increasing your chance of getting an infection. If you can, avoid people with infections. Check with your doctor right away if you think you are getting an infection or if you have a fever or chills, sore throat, sores in the mouth, lower back or side pain, or painful or difficult urination.

Do not suddenly stop taking this medicine without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping completely. This may help prevent a possible worsening of your condition and reduce the possibility of withdrawal symptoms such as headache, nausea, or a general feeling of discomfort or illness.

This medicine may increase your weight. Your doctor may need to check your weight on a regular basis while you are using this medicine.

Mirtazapine may cause drowsiness, trouble with thinking, or trouble with controlling body movements. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that requires you to be alert, well-coordinated, and able to think well.

This medicine may cause serious skin reaction, including drug reaction with eosinophilia and systemic symptoms (DRESS). Check with your doctor right away if you have black, tarry stools, chest pain, chills, cough, fever, painful or difficult urination, sore throat, sores, ulcers, or white spots on the lips or in the mouth. swollen glands, unusual bleeding or bruising, or unusual tiredness or weakness.

Hyponatremia (low sodium in the blood) may occur with this medicine. This is more common in elderly patients, those who are taking diuretic medicines for high blood pressure, or those who have decreased amounts of fluid in the body due to severe diarrhea or vomiting. Check with your doctor right away if you have confusion, difficulty concentrating, headaches, memory problems, weakness, and unsteadiness.

Dizziness, lightheadedness, or fainting may occur, especially when you get up suddenly from a lying or sitting position. Getting up slowly may help. If this problem continues or gets worse, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn't Take Remeron?

You should not take Remeron if you:

• Take monoamine oxidase inhibitors (MAOIs) or within 14 days of initiating or discontinuing MAOIs
• Have a known allergy to the medication or any of its components

People with a rare genetic disease called phenylketonuria should not take the orally disintegrating tablets, as they contain phenylalanine. The regular tablets do not contain phenylalanine.

Notify your healthcare provider if you become pregnant or plan to become pregnant while taking Remeron. If you are pregnant or breastfeeding, you'll need to weigh the risks and benefits of Remeron and other options with your physician. It's usually recommended only if the drug is needed.

Remeron also might not be the best choice for someone who has bipolar depression. Starting Remeron might trigger the manic phase of their disease. Contact your mental health care provider right away if you experience manic symptoms––like fast thinking and impulsivity––after starting Remeron.

What Other Medications Interact With Remeron?

You should never take Remeron along with MAOIs, another type of medication used to treat depression. Taking both types of medications can lead to a serious problem known as serotonin syndrome.

Other drugs that might trigger serotonin syndrome when taken with Remeron include:

• Other antidepressants such as selective serotonin reuptake inhibitors (SSRIs) like Prozac (fluoxetine) and serotonin-norepinephrine reuptake inhibitors (SNRIs) like Cymbalta (duloxetine)
• Certain drugs used for migraines, such as "triptan" drugs like Imitrex (sumatriptan)
• Certain pain-relieving drugs, like Ultram (tramadol)
• Some drugs used for anxiety, like Buspar (buspirone)
• Drugs used for bipolar depression, such as lithium
• Some over-the-counter products, like St. John's wort

Several drugs can also increase the risk of heart rhythm issues if taken with Remeron, including:

• Anti-arrhythmic drugs, like Pronestyl (procainamide)
• Antipsychotic drugs, like Haldol (haloperidol) or Risperdal (risperidone)
• Certain antibiotics, like Levaquin (levofloxacin)

This is not a complete list of the drugs that might interact with Remeron. It doesn't necessarily mean that you wouldn't be able to take these medications if needed. Sometimes your healthcare provider might be able to adjust a drug's dose. Or you might need better monitoring (e.g., if you are taking a drug that affects your blood clotting, like warfarin). But you should be aware of this issue and discuss all your medications with your provider.

What Medications Are Similar?

Remeron is an atypical antidepressant, meaning that it isn't among a group of similar drugs available on the U.S. market. 

However, multiple other groups of antidepressant drugs are available. Your healthcare provider may make an initial suggestion for you based on your medical conditions and your personal preferences. However, finding the right one for you can involve some trial and error.

Some of the major groups of antidepressant drugs are:

• SSRIs
• SNRIs
• MAOIs 
• Tricyclic antidepressants

Several other types of atypical depressants also exist. These don't fit neatly into another drug category.

Remeron is more closely chemically related to tricyclic antidepressants than to these other groups. However, compared with tricyclics, it seems to cause fewer side effects like dry mouth and potentially fewer severe side effects related to heart problems. Compared with SSRIs, Remeron may be less likely to cause sexual dysfunction as a side effect.

Compared with some other types of antidepressant drugs, Remeron may have certain benefits for certain people. For example, some evidence suggests that it may be more likely to help people with any of the following:

• Anxiety coexisting with depression
• Depression that hasn't responded well to other treatments
• Geriatric depression

Please note, these groups of drugs are possible alternatives to Remeron. They aren't usually prescribed at the same time. This is especially important for MAOIs, which you should never take at the same time as Remeron.

Frequently Asked Questions

• Remeron might be more likely to cause weight gain than some of the other antidepressant options. One of the most commonly reported side effects of mirtazapine is increased appetite. It might specifically increase your cravings for carbohydrates. Not surprisingly, this can lead to weight gain in some people.

  You can discuss other possible choices with your healthcare provider.

• This can vary. However, Remeron may start to work more quickly than some other types of antidepressants. For example, with Remeron, you might notice improvement within a week or two. For some other types of antidepressants, like SSRIs, you might not notice improvement for another few weeks.

  Some people also notice an improvement in some symptoms before others. For example, you might notice you are sleeping better before you notice that your mood is more positive.

• Serotonin syndrome is a very rare problem, but a potentially serious one. However, the risk is much greater if you take more of the drug than is prescribed. It is also increased if you take other drugs in addition to Remeron that alter serotonin (such as other antidepressants).

  You should never take a drug called a monoamine oxidase inhibitor (MAOI) along with Remeron, because this could trigger the syndrome.

How Can I Stay Healthy While Taking Remeron?

Remeron is a safe drug for most people, one that can bring life-changing relief to debilitating symptoms of depression. Although learning about potential side effects can be scary, it's better to have some understanding of possible issues. If you use the drug as prescribed, it is very unlikely that you will have serious problems.

Have an open dialogue with your healthcare provider about the risks and benefits of treatment for your particular situation. And if you do notice any unusual symptoms after starting the drug, contact your healthcare professional right away.

Medical Disclaimer

Verywell Health's drug information is meant for education purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.