Without access to personalized care, depression can feel frustrating and overwhelming. Taking medication can be a significant step towards improving someone’s mental health.

One common medication often used to treat Major Depressive Disorder is mirtazapine, which is often known by the brand name Remeron. This page outlines some important information about mirtazapine.

What is mirtazapine?

What is mirtazapine? How does it work?

Mirtazapine is an antidepressant medication approved to treat conditions such as Major Depressive Disorder. Mirtazapine may sometimes be used off-label to treat insomnia, Panic DIsorder, PTSD, OCD, Generalized Anxiety Disorder, Social Anxiety Disorder, headaches, or migraines.

Mirtazapine belongs to a class of medications called SNRIs, or Serotonin-Norepinephrine Reuptake Inhibitors. SNRIs such as mirtazapine help increase the levels of the neurotransmitters serotonin and norepinephrine in the brain. Serotonin and norepinephrine are chemical messengers which regulate mood, emotions and sense of well being. Increased levels of these neurotransmitters can help improve how we feel. 

How is mirtazapine typically used?

A common regimen of mirtazapine for adults is 15mg or 30mg per day, usually taken at bedtime. However, your prescription might differ depending on your medical history and the particular condition for which you are receiving treatment. Often, doctors will start their patients off on a lower dose and gradually increase the dosage every 1-2 weeks or so, until reaching an appropriate therapeutic daily dosage. This gradual increase helps avoid unpleasant or adverse responses. As a result, it might take some time to begin seeing the full benefits of mirtazapine, but it is still important to consistently take your medication and follow your doctor’s recommendations. 

Do not stop taking mirtazapine without talking to your doctor, as this may cause a negative reaction. If your doctor feels that you are ready to stop taking mirtazapine, they will gradually reduce your dose over several weeks until it is safe to stop taking the medication altogether. 

What are some possible side effects?

Some common side effects(also known as adverse effects) of mirtazapine include:

• Constipation
• Increased appetite
• Dry mouth
• Drowsiness
• Dizziness 

Some serious(but uncommon) side effects include:

• Flu-like symptoms, fever, chills, sore throat, mouth sores, or other signs of infection
• Chest pain
• Rapid heartbeat
• Seizures 

Call 911 or seek emergency care if you notice any severe side effects. You can find a more comprehensive list of mirtazapine side effects here. 

Why do these side effects occur? 

Any medication can potentially lead to side effects. A person’s likelihood of having side effects depends on many factors, including genetics, age, lifestyle, and the type of medication itself. Side effects may occur because drugs often have broad or poorly targeted effects, or the drug target itself may have many downstream effects on the body. For example, though mirtazapine targets serotonin and norepinephrine to help improve mood, there are other systems which are affected by these neurotransmitters, and unusual changes in serotonin and norepinephrine levels can lead to side effects. 

Many non-serious side effects of mental health medications such as mirtazapine go away after a few weeks as your body gets used to the medication. However, if a side effect persists, is intolerable, or severely hinders your ability to go about your daily life, talk to your doctor because this might be a sign that the medication is not a good fit. Your doctor may then recommend a dose adjustment or a change of medication.

How do your genes relate to mirtazapine? 

Genetics can affect your body’s response to medication. Your genes contain the blueprints and instructions to create enzymes that break down medications. The CYP2D6, CYP1A2, and CYP3A4 genes produce enzymes which are responsible for the metabolism of mirtazapine. 

Some people with certain variations of these genes might be slow metabolizers for mirtazapine. Being a slow metabolizer means that your body breaks down mirtazapine more slowly than other people do which means that the drug sticks around longer which may lead to side effects. For slow metabolizers, a doctor might opt to prescribe a different medication or prescribe a lower dosage.

One way to predict whether you will have a positive outcome while taking mirtazapine is by taking a DNA test to determine what genetic variations you have and how they might affect medication metabolism. Your genetic(DNA) test results can help your doctor avoid less suitable medications and make more informed decisions so that you can get better, faster.

Special Precautions

• Mirtazapine should not be taken alongside monoamine oxidase inhibitors(MAOs)
• Avoid alcohol when taking mirtazapine as the combination can impair cognitive and motor skills.
• Notify your doctor if you are pregnant or are planning to become pregnant before taking mirtazapine. 
• Notify your doctor if you experience a sore throat, fever, or any signs of infection while taking mirtazapine. This might be an indicator of a low white blood cell(WBC) count, and you may need to stop taking the medication. 

If you show signs of an allergic reaction to mirtazapine(hives, difficulty breathing, rash, swelling), call 911 or go to the nearest emergency department.

Some medications, vitamins, and herbs may interfere with how mirtazapine works. Make sure to tell your doctor about all other medications you are taking before starting mirtazapine to avoid negative drug interactions. For full details, see the FDA’s full list of precautions.

Looking to find the right medication for your mental health? Join Prairie today to connect to expert providers and affordable medication options.