Skip Ribbon Commands
Skip to main content


Drug Class: Commonly Known As: Category:
Serotonin and Noradrenaline Reuptake Inhibitors (SNRI) remeron Adult

Mirtazapine - Side Effects, Precautions, and Contraindications

What side effects can Mirtazapine cause?

Common side effects that generally affect up to 10% of patients include:

  • Tiredness, drowsiness
    • Avoid driving or taking part in activities that requires concentration.
    • Discuss with your doctor if you can take your medication at a different time of the day if it affects you.
  • Increase in appetite, weight gain
    • Monitor your weight, exercise regularly and eat a healthy, balanced diet.
  • Dry mouth
    • Chew sugar-free gum, suck on sugar-free hard candies or ice chips, sip water regularly.
  • Constipation
    • Drink more water (if you do not have any fluid restriction), eat more high-fibre foods, and exercise regularly.
    • Consult a doctor or pharmacist if you think you need medication to relieve your condition.
  • Dizziness
    • Get up slowly from sitting or lying down position.
  • Headache
    • Speak with your doctor if it affects your daily life.

Most of the side effects listed here will improve with time. Speak with your doctor or pharmacist if they continue, get worse or are affecting your daily life.

Very rarely (affects less than 1% of patients) this medication may cause:

  • Swelling in hands, ankles or feet
  • Flu-like symptoms (fever, chills, sore throat); mouth sores / ulcers
  • Severe vomiting or diarrhoea, loss of appetite, stomach pain 
  • Unexplained fever, confusion, fast heartbeat, severe weakness, uncontrolled movements or twitching of muscles (signs and symptoms of Serotonin syndrome)
  • Feelings of irritability, intense agitation or anxiety, restlessness
  • Unusual thoughts; talking, feeling, and acting with excitement that you cannot control
  • Fits (seizures)

The symptoms of a drug allergy include one or more of the following:

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and consult your healthcare professional immediately.

Before taking Mirtazapine , what precautions must I follow?

Inform your healthcare professional if:

  • You are allergic to this medication or any of the other ingredients of this medication.
  • You are pregnant, planning to become pregnant, or breastfeeding. If you are pregnant or breastfeeding, your doctor would have discussed the potential benefits and side-effects with you and should you have further questions or concerns, do consult your doctor.
  • You are unable to take artificial sweeteners. Mirtazapine orodispersible tablets contain aspartame, a type of artificial sweetener.
  • You have or have ever had:
    • Other drug allergies
    • An increase in the level of phenylalanine in the blood (also known as phenylketonuria, a genetic disorder)
    • Heart, kidney or liver disease
    • Medical conditions such as fits (seizures), urinary problems, diabetes, high cholesterol, low blood pressure
    • Other mental health conditions such as bipolar disorder, abnormally high or excited mood (mania)


In some cases, particularly in young people below the age of 25 years, this medication may cause the following changes to a person's mental condition, especially in the first few weeks of treatment or during dose changes:

  • New or worsening thoughts of harming yourself or ending your life
  • Worsening agitation, restlessness, violent behaviour, or
  • Other changes in mood or behaviour

Please inform your doctor as soon as possible, or for your family or caregiver to inform your doctor if you are unable to seek treatment on your own.

Do not stop taking this medication on your own without discussing with your doctor.

It is important to note that your doctor has prescribed this medication as he/she feels you will benefit more from taking this medication over the possible risks that it may cause, which have a low chance of occurring, and most people take this medication without any of such problems.

What food or medicine must I avoid when I take Mirtazapine ?

Avoid drinking alcohol while taking Mirtazapine as it can worsen the symptoms of your depression, increase anxiety, and cause excessive drowsiness. This medication may interact with other medications. If you intend to take any over the counter medication, supplements, herbal remedy or traditional Chinese medicine, consult your doctor or healthcare professional first to confirm that it is safe to take with Mirtazapine.

Mirtazapine - Additional Information

  • Updated on 5/31/2021 12:00:00 AM
  • Article contributed by PSS National Medication Information Workgroup PSS National Medication Information Workgroup
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

Find Your Medicines