Medically reviewed by Jessica Swirble, PharmD
Last updated on 6/18/2024

Drug Information | Side Effects | Use & Dosage | Request a Prescription

The use of mirtazapine can lead to various side effects in some individuals.

Common mild side effects of mirtazapine use include:

• Dry mouth
  
• Increased appetite
  
• Weight gain
  
• Constipation
  
• Drowsiness
  
• Dizziness
  
• Weakness
  
  

More severe side effects include:

• Chest pain
  
• Fast or pounding heartbeat
  
• Seizures
  
• Increased cholesterol
  
• Flu symptoms (like fever, chills, sore throat, sores in the mouth)
  
• Severe changes in mood
  
  

If you experience any severe or concerning side effects while taking mirtazapine, contact your healthcare provider right away.

Inform your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with mirtazapine. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with mirtazapine.

Tell your provider if you are taking these medications or supplements:

• Alpha-2 agonists (clonidine, guanfacine, tizanidine)
  
• Anticoagulants (blood thinners)
  
• Antidepressants
  
• Antifungals
  
• Anxiolytics
  
• Anticonvulsants
  
• Histamine H2-receptor antagonists
  
• Benzodiazepines
  
• Macrolide antibiotics
  
• Opioids
  
• Mood stabilizers
  
• Migraine medications
  
• Antiretrovirals
  
• Parkinson’s medications
  
• Sedatives
  
• Selective serotonin reuptake inhibitors (SSRIs)
  
• Serotonin-norepinephrine reuptake inhibitors (SNRIs)
  
• Sleeping pills
  
• Tranquilizers
  
• St. John’s wort
  
  

You should also mention medical conditions such as:

• Heart attack
  
• Low blood pressure
  
• High cholesterol
  
• Glaucoma
  
• Mental health conditions
  
• Heart disease
  
• Liver disease
  
• Kidney disease
  
• Seizures
  
• Diabetes
  
  

If you are pregnant, planning to become pregnant, or breastfeeding, discuss the potential risks and benefits of using mirtazapine with your healthcare provider.

Take mirtazapine exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment.

Your provider may direct you to avoid alcohol while taking mirtazapine, as it can increase the risk of side effects.

Mirtazapine can cause drowsiness. Do not drive or operate machinery until you know how this medication affects you.

Complete the full course of treatment, even if you feel better, to ensure the medication's effectiveness in managing your symptoms.

In case of a mirtazapine overdose, seek medical attention immediately. Symptoms of overdose may include severe drowsiness, confusion, rapid heartbeat, or fainting. If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.