Remeron (Mirtazapine): Uses, Dosage, Side Effects, & More

How Does Mirtazapine Work?

Remeron can help improve depression by causing the increased release of serotonin and norepinephrine in the brain. These chemicals play an important role in mood regulation, sleep, and appetite. When these levels are low or dysregulated, it can cause depression symptoms. By increasing the amount of these chemicals in the brain, an individual who has depression can feel less down and more like themselves again.

Is Remeron Similar to Xanax?

Remeron (mirtazapine) and Xanax (alprazolam) are different medications, and each are intended to address different disorders. Remeron is primarily used as an antidepressant and prescribed for the treatment of major depressive disorder.² Xanax, however, is a benzodiazepine used as an anti-anxiety medication. Remeron is typically used for long-term relief of depression symptoms. In contrast, Xanax is often used for rapid relief of anxiety symptoms.

What Is Mirtazapine Used to Treat?

Mirtazapine is FDA-approved for the treatment of major depressive disorder in adults.² When a medication is FDA-approved, it means that the U.S. Food and Drug Administration has reviewed and confirmed the drug’s safety and effectiveness for a specific condition. Mirtazapine is not approved for use in children.

Mirtazapine is occasionally used off-label. This means that the medication is being used for a non-FDA-approved condition. Prescribers will use a medication off-label because, in their professional judgment, they believe it may still offer a benefit to someone.

Off-label uses of mirtazapine include:^3,4

• Panic disorder
• Generalized anxiety disorder
• Posttraumatic stress disorder (PTSD)
• Insomnia
• Chronic tension-type headache
• Social anxiety disorder
• Fibromyalgia

Mirtazapine Warnings & Precautions

When considering mirtazapine, it is important to be aware of the associated warnings and precautions. It is important to inform your health provider of all current medical conditions, such as if you have a history of heart problems, liver problems, or seizures.

During treatment with mirtazapine, it is essential to monitor for any sudden changes in mood or behavior, as antidepressants like mirtazapine may increase the risk of suicidal thoughts.¹ If you are experiencing worsening depression or unusual changes in behavior, you should seek medical attention immediately.

Precautions for taking mirtazapine include:^1,2

• Suicidal thoughts and behaviors: Antidepressants are associated with a risk of increased suicidal thoughts/behaviors, particularly in adolescents and young adults.
• Low white blood count: Mirtazapine may decrease white blood cells in the body, increasing the risk for infection. If you develop signs of infection with a low white blood cell count, mirtazapine may need to be discontinued.
• Serotonin syndrome: Taking mirtazapine with other medications that increase serotonin can cause serotonin syndrome. Symptoms may include mental status changes, rapid heart rate, changes in blood pressure, seizures, and nausea/vomiting.
• Glaucoma: Mirtazapine may worsen glaucoma in patients at risk for angle-closure glaucoma.
• Heart conditions: Mirtazapine can increase the risk of dangerous heart rhythms in those with a history of QT prolongation or a family history of QT prolongation.
• Increased appetite and weight gain: Mirtazapine can cause an increase in appetite leading to excessive weight gain.
• Drowsiness: Mirtazapine can cause drowsiness, especially when starting the medication. Because of this, caution should be taken when operating heavy machinery or motor vehicles.
• Mania: Patients with bipolar disorder may be at an increased risk of manic episodes when taking antidepressants such as mirtazapine.
• Seizures: Mirtazapine would be prescribed with caution in those with a seizure disorder.
• Elevated cholesterol and triglycerides: Mirtazapine may increase cholesterol and triglycerides.
• Low blood sodium: Mirtazapine may cause low blood sodium levels leading to headaches, difficulty concentrating, weakness, and unsteadiness.
• Liver injury: Mirtazapine may lead to elevated liver proteins in the blood (AST and ALT). This can resolve with continued use of mirtazapine, but others may need to stop the medication.
• Discontinuation syndrome: Some individuals may experience antidepressant discontinuation syndrome when stopping treatment with mirtazapine. This can cause a variety of symptoms, including dizziness, anxiety, fatigue, and nausea.
• Use during pregnancy: Mirtazapine during pregnancy has not been reliably studied, but no risks have been identified. Continuing mirtazapine during pregnancy should be discussed with an individual’s healthcare team.
• Use when breastfeeding: Mirtazapine is excreted in breastmilk at low levels. No adverse effects have been reported on breastfed infants of mothers taking mirtazapine. Continuing mirtazapine while breastfeeding should be discussed with an individual’s healthcare team.

Interactions With Mirtazapine

It is important to be aware of the potential interactions between mirtazapine and other medications, substances, and herbs. Some medications, such as monoamine oxidase inhibitors (MAOIs), can increase the risk of severe side effects and serotonin syndrome. Other substances can affect the concentration of mirtazapine in the blood, impacting the effectiveness of treatment.

Nine substances you should avoid while taking mirtazapine include:¹

• Monoamine oxidase inhibitors (MAOIs): Taking mirtazapine with MAOIs can increase the risk of serotonin syndrome and severe side effects. MAOIs include selegiline, tranylcypromine, and isocarboxazid.
• Other drugs that increase serotonin: Taking other medications that increase serotonin can increase the risk of serotonin syndrome and severe side effects. Examples of these medications and herbs include selective serotonin reuptake inhibitors (SSRIs), selective norepinephrine reuptake inhibitors (SNRIs), and St. John’s Wort.
• Strong CYP3A inducers: Some drugs can increase the removal of mirtazapine from the body, decreasing its effect. Examples of these medications include phenytoin, carbamazepine, and rifampin.
• Strong CYP3A inhibitors: Some drugs can decrease the removal of mirtazapine from the body, increasing the risk of side effects. Examples of these medications include itraconazole, ritonavir, and nefazodone.
• Cimetidine: Cimetidine is a medication used to decrease acidity in the stomach. Taking this medication with mirtazapine can increase the concentration of mirtazapine in the body and increase the risk of side effects.
• Benzodiazepines: Benzodiazepines can increase the risk of drowsiness when taking mirtazapine.
• Alcohol: Alcohol can increase the risk of drowsiness when taking mirtazapine.
• Drugs that prolong the QTc interval: Prolongation of the QTc interval can increase the risk of serious heart rhythm problems. Taking medications that prolong the QTc interval with mirtazapine can increase this risk.
• Warfarin: Mirtazapine can enhance the effect of warfarin, leading to an increased risk of bleeding.

Side Effects of Mirtazapine

Mirtazapine can cause a variety of different side effects. While not everyone will experience side effects, it is important to be aware of the possibilities. Most side effects are mild and resolve over time. Other side effects, however, can be more severe or persistent and may require immediate medical attention.

Common Side Effects of Mirtazapine

The most common side effects of mirtazapine are mild and resolve over time. These side effects include drowsiness, increased appetite, weight gain, and dizziness. It is important to remember that individual reactions vary, and discussing side effects with your healthcare provider will help ensure the best course of action for your well-being.

Common side effects of mirtazapine include:¹

• Drowsiness
• Increased appetite
• Weight gain
• Dizziness
• Flu-like symptoms
• Dry mouth
• Constipation
• Dizziness
• Increased sex drive

Serious Side Effects of Mirtazapine

While mirtazapine is typically well tolerated, there is a risk of developing serious side effects. If you are experiencing serious side effects, it is important to notify your healthcare provider immediately. Other side effects may require immediate medical evaluation in the emergency department.

Serious side effects of mirtazapine may include:^1,2

• Allergic reactions
• Serotonin syndrome
• Seizures
• Suicidal thoughts
• Abnormal heart rhythm

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

Antidepressant Discontinuation

Stopping mirtazapine can lead to antidepressant discontinuation syndrome, also known as antidepressant withdrawal.¹ The symptoms of discontinuation syndrome include dizziness, abnormal dreams, anxiety, fatigue, and confusion. These symptoms are typically mild, but if severe symptoms occur, immediate medical care may be needed.

The risk for discontinuation syndrome increases when stopping the medication abruptly. A gradual tapering of the mediation under the guidance of a healthcare provider can minimize the risk of developing these symptoms.

Allergic Reactions to Mirtazapine

Allergic reactions to mirtazapine are possible, though they are rare. Individuals with a history of allergies to mirtazapine itself or to other antidepressants should exercise caution when taking this medication. It is important to discuss any known allergies with your healthcare provider before starting mirtazapine.

Allergic reactions to mirtazapine may include:¹

• Hives
• Itching
• Swelling of the face, mouth, or throat
• Difficulty breathing
• Rapid heart rate
• Dizziness
• Drop in blood pressure
• Nausea and vomiting

If you are experiencing an allergic reaction when taking mirtazapine, seek immediate medical attention immediately. Allergic reactions can lead to serious complications and even death if not treated. If confirmed as an allergic reaction, mirtazapine would need to be discontinued. In this case, your healthcare provider will be able to provide alternative options, including other antidepressant medications.

Mirtazapine Dosages for FDA-Approved Treatment

Mirtazapine is FDA-approved for the treatment of major depressive disorder in adults. FDA-approved medications are medications that have undergone rigorous testing and meet the safety and effectiveness requirements of the U.S. Food and Drug Administration.

The dosage of mirtazapine can vary depending on an individual’s response to the medication, the severity of the condition, and medical history. The typical starting dose of mirtazapine is 15 mg. This dose can be increased every 1-2 weeks to a maximum of 45 mg.

Mirtazapine Forms & Strengths

Mirtazapine is available in different forms and strengths to meet an individual’s treatment needs. These forms include tablets and orally disintegrating tablets, with dosages ranging from 15 mg to 45 mg. The choice of form and strength is determined by factors such as the disorder being treated, the age of the patient, the severity of symptoms, and the individual’s medical history.

After a thorough evaluation, a healthcare provider will be able to determine the best form and starting dosage for each individual. Some individuals, such as the elderly or those taking other medications, may require a lower starting dose. When starting the medication, improvements in sleep and anxiety may be noticed within 1-2 weeks.³ The improvement of depressive symptoms, however, typically takes 2-4 weeks and may take as long as 6-8 weeks.³

Mirtazapine is available in the following forms and strengths:²

• 15 mg tablet
• 30 mg tablet
• 15 mg orally disintegrating tablet
• 30 mg orally disintegrating tablet
• 45 mg orally disintegrating tablet

It is important to remember to take mirtazapine as prescribed by your healthcare provider. Regular tablets should be swallowed whole. Orally disintegrating tablets should be placed on the tongue and be allowed to fully disintegrate without chewing or crushing. Once disintegrated, it can be swallowed.²

How Should I Take Mirtazapine?

It is usually recommended that mirtazapine be taken at night, as it may cause drowsiness. It can be taken with or without food. The regular tablets should be swallowed whole. The orally disintegrating tablets should be placed on the tongue and allowed to fully disintegrate before swallowing. Following your healthcare provider’s instructions on how best to take the medication is essential.

What Happens If I Miss a Dose of Mirtazapine?

If you forget to take a dose of mirtazapine, take the missed dose as soon as you remember it. However, if it is close to the time of your next dose, skip the missed dose and take the medication on your regular dosing schedule. Do not take two doses to make up for a missed dose.

Can You Overdose on Mirtazapine?

It is possible to overdose on mirtazapine if taken at higher doses than recommended. Symptoms of overdose include disorientation, drowsiness, memory problems, and rapid heart rate.²

What Should You Do If You Take Too Much Mirtazapine?

If you or someone you know has taken too much mirtazapine, call the poison control helpline at 1-800-222-1222. If more severe symptoms occur, such as seizures, trouble breathing, or coma, immediately seek emergency services by calling 911.

Questions to Ask Your Healthcare Provider About Remeron (Mirtazapine)

If you are considering mirtazapine for treatment, it is important to discuss this with your doctor, psychiatrist, and therapist. Your healthcare team will be able to determine if mirtazapine is a suitable option for you. You may want to inquire about the potential benefits, risks, and side effects of mirtazapine. If you are looking for a new prescriber, online psychiatry services are a great option. These services offer the opportunity to connect with qualified professionals from the comfort of your home.

Questions to ask your care team about mirtazapine include:

• How long will it take for me to adjust to taking mirtazapine?
• 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?
• Are there any lifestyle changes to consider when taking this medication?
• Do I need to change my diet when taking mirtazapine?
• What signs should I watch out for that may indicate a dosage change is necessary?
• How will I know if mirtazapine is helping with my depressive symptoms?
• What can I do to manage potential side effects?
• How can I reduce my risk of experiencing mirtazapine withdrawal?

In My Experience

In my experience, mirtazapine is a great option for the treatment of major depressive disorder. Mirtazapine is not commonly the first antidepressant prescribed when treating depression. Still, it is a great option to consider, especially for those who have failed treatment with other antidepressants. It is important to remember that treatment for depression can take time, and there are many medications available for treatment.

For Further Reading

• How to Get Antidepressants: Everything You Need to Know – Choosing Therapy
• How Do Antidepressants Make You Feel? Possible Side Effects & Changes
• Mental Health Conditions: Depression and Anxiety
• Mirtazapine for Anxiety: All You Need to Know