Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

1. Remeron
2. Remeron Soltab

Canadian Brand Name

1. Remeron RD

Descriptions

Mirtazapine is used to treat depression. Mirtazapine belongs to a group of medicines called tetracyclic antidepressants. These medicines work in the central nervous system (CNS) to make certain chemicals in the brain stronger.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

• Tablet, Disintegrating
• Tablet

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of mirtazapine in the pediatric population. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of mirtazapine in the elderly. However, elderly patients are more likely to have confusion or unusual drowsiness and age-related liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving mirtazapine.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Bepridil
• Bromopride
• Cisapride
• Dronedarone
• Fluconazole
• Furazolidone
• Iproniazid
• Isocarboxazid
• Linezolid
• Mesoridazine
• Methylene Blue
• Moclobemide
• Nialamide
• Phenelzine
• Pimozide
• Piperaquine
• Posaconazole
• Procarbazine
• Rasagiline
• Safinamide
• Selegiline
• Sparfloxacin
• Terfenadine
• Thioridazine
• Tranylcypromine
• Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Alfentanil
• Alfuzosin
• Almotriptan
• Alprazolam
• Amineptine
• Amiodarone
• Amisulpride
• Amitriptyline
• Amitriptylinoxide
• Amoxapine
• Amphetamine
• Anagrelide
• Anileridine
• Apalutamide
• Apomorphine
• Aripiprazole
• Aripiprazole Lauroxil
• Arsenic Trioxide
• Asenapine
• Astemizole
• Atazanavir
• Azithromycin
• Bedaquiline
• Bentazepam
• Benzhydrocodone
• Benzphetamine
• Boceprevir
• Bromazepam
• Brompheniramine
• Buprenorphine
• Bupropion
• Buserelin
• Buspirone
• Butorphanol
• Carbamazepine
• Ceritinib
• Chlordiazepoxide
• Chloroquine
• Chlorpheniramine
• Chlorpromazine
• Ciprofloxacin
• Citalopram
• Clarithromycin
• Clobazam
• Clofazimine
• Clomipramine
• Clonazepam
• Clonidine
• Clorazepate
• Cloxazolam
• Clozapine
• Cobicistat
• Cocaine
• Codeine
• Conivaptan
• Crizotinib
• Cyclobenzaprine
• Dabrafenib
• Dasatinib
• Degarelix
• Delamanid
• Delorazepam
• Desipramine
• Deslorelin
• Desvenlafaxine
• Deutetrabenazine
• Dextroamphetamine
• Dextromethorphan
• Diazepam
• Dibenzepin
• Difenoxin
• Dihydrocodeine
• Diphenoxylate
• Disopyramide
• Dofetilide
• Dolasetron
• Domperidone
• Donepezil
• Doxepin
• Droperidol
• Duloxetine
• Ebastine
• Efavirenz
• Eletriptan
• Encorafenib
• Entrectinib
• Enzalutamide
• Eribulin
• Erythromycin
• Escitalopram
• Estazolam
• Ethylmorphine
• Famotidine
• Felbamate
• Fenfluramine
• Fentanyl
• Fingolimod
• Flecainide
• Flunitrazepam
• Fluoxetine
• Flurazepam
• Fluvoxamine
• Formoterol
• Foscarnet
• Fosphenytoin
• Frovatriptan
• Galantamine
• Gatifloxacin
• Gemifloxacin
• Gepirone
• Glasdegib
• Gonadorelin
• Goserelin
• Granisetron
• Halazepam
• Halofantrine
• Haloperidol
• Histrelin
• Hydrocodone
• Hydromorphone
• Hydroquinidine
• Hydroxyamphetamine
• Hydroxychloroquine
• Hydroxytryptophan
• Hydroxyzine
• Ibutilide
• Idelalisib
• Iloperidone
• Imipramine
• Indinavir
• Inotuzumab Ozogamicin
• Itraconazole
• Ivabradine
• Ivosidenib
• Ketazolam
• Ketobemidone
• Ketoconazole
• Lapatinib
• Lasmiditan
• Lenvatinib
• Leuprolide
• Levofloxacin
• Levomilnacipran
• Levorphanol
• Lisdexamfetamine
• Lithium
• Lofepramine
• Lofexidine
• Lopinavir
• Loprazolam
• Lorazepam
• Lorcaserin
• Lormetazepam
• Lumacaftor
• Lumefantrine
• Macimorelin
• Medazepam
• Mefloquine
• Melitracen
• Meperidine
• Metaclazepam
• Metaxalone
• Methadone
• Methamphetamine
• Methotrimeprazine
• Metronidazole
• Midazolam
• Mifepristone
• Milnacipran
• Mitotane
• Mizolastine
• Moricizine
• Morphine
• Morphine Sulfate Liposome
• Moxifloxacin
• Nafarelin
• Nalbuphine
• Naratriptan
• Nefazodone
• Nelfinavir
• Nicomorphine
• Nilotinib
• Nitrazepam
• Nordazepam
• Norfloxacin
• Nortriptyline
• Octreotide
• Ofloxacin
• Olanzapine
• Oliceridine
• Ondansetron
• Opipramol
• Opium
• Opium Alkaloids
• Osilodrostat
• Osimertinib
• Oxaliplatin
• Oxazepam
• Oxycodone
• Oxymorphone
• Paliperidone
• Palonosetron
• Panobinostat
• Papaveretum
• Papaverine
• Paregoric
• Paroxetine
• Pasireotide
• Pazopanib
• Pentamidine
• Pentazocine
• Perphenazine
• Phenytoin
• Pimavanserin
• Pinazepam
• Pipamperone
• Piritramide
• Pitolisant
• Prazepam
• Probucol
• Procainamide
• Prochlorperazine
• Promethazine
• Propafenone
• Protriptyline
• Quazepam
• Quetiapine
• Quinidine
• Quinine
• Ranolazine
• Remifentanil
• Remimazolam
• Ribociclib
• Rifampin
• Risperidone
• Ritonavir
• Rizatriptan
• Saquinavir
• Selpercatinib
• Sertindole
• Sertraline
• Sevoflurane
• Sibutramine
• Siponimod
• Sodium Phosphate
• Sodium Phosphate, Dibasic
• Sodium Phosphate, Monobasic
• Solifenacin
• Sorafenib
• Sotalol
• St John's Wort
• Sufentanil
• Sulpiride
• Sultopride
• Sumatriptan
• Sunitinib
• Tacrolimus
• Tamoxifen
• Tapentadol
• Telaprevir
• Telavancin
• Telithromycin
• Temazepam
• Tetrazepam
• Tianeptine
• Tilidine
• Tolterodine
• Toremifene
• Tramadol
• Trazodone
• Triazolam
• Triclabendazole
• Trimipramine
• Triptorelin
• Tryptophan
• Vandetanib
• Vardenafil
• Vemurafenib
• Venlafaxine
• Vilanterol
• Vilazodone
• Vinflunine
• Voriconazole
• Vorinostat
• Vortioxetine
• Warfarin
• Zolmitriptan
• Zotepine
• Zuclopenthixol

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Cimetidine

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Tobacco

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Ethanol

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Angina (severe chest pain), history of or
• Blood vessel disease or circulation problems or
• Dehydration or
• Heart attack, history of or
• Heart disease or
• Hypotension (low blood pressure) or
• Hypovolemia (low blood volume) or
• Stroke, history of—May cause side effects to become worse.

• Bipolar disorder (mood disorder with mania and depression) or
• Glaucoma, angle-closure or
• Heart rhythm problems (eg, QT prolongation) or
• Hypercholesterolemia (high cholesterol in the blood) or
• Hyponatremia (low sodium in the blood) or
• Mania or hypomania, history of or
• Seizures, history of—Use with caution. May make these conditions worse.

• Kidney disease, moderate or severe or
• Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

• Phenylketonuria (a metabolic disorder)—The orally disintegrating tablet contains aspartame, which can make this condition worse.

Proper Use

Take this medicine exactly as directed by your doctor in order to improve your condition as much as possible. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine should come with a Medication Guide. Read and follow these instructions carefully. Ask your doctor if you have any questions.

To use the orally disintegrating tablet:

• Make sure your hands are dry before you handle the tablet.
• Do not open the blister pack that contains the tablet until you are ready to take it.
• Do not push the tablet through the foil backing of the package. Instead, gently peel back the foil backing and remove the tablet.
• Immediately place the tablet on top of the tongue. Do not break or split the tablet.
• The tablet will dissolve in seconds, and you may swallow it with your saliva. You do not need to drink water or other liquids to swallow the tablet.

Dosing

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.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep the orally disintegrating tablet in the original package until you are ready to take it.

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.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

1. Decreased or increased movement
2. mood or mental changes, including abnormal thinking, agitation, anxiety, confusion, and feelings of not caring
3. skin rash
4. swelling
5. trouble breathing

Rare

1. Change in menstrual cycle (periods)
2. chills
3. decreased sexual ability
4. fever
5. menstrual pain
6. mood or mental changes, including anger, feelings of being outside the body, mood swings, and unusual excitement
7. mouth sores
8. seeing, hearing, or feeling things that are not there
9. seizures
10. sore throat

Incidence not known

1. Black, tarry stools
2. blistering, peeling, loosening of skin
3. chest pain
4. fainting
5. hives, itching, skin rash
6. irregular or slow heart rate
7. joint or muscle pain
8. painful or difficult urination
9. red, irritated eyes
10. red skin lesions, often with a purple center
11. sore throat
12. sores, ulcers, or white spots on the lips or in the mouth
13. swollen glands
14. unusual bleeding or bruising
15. unusual tiredness or weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

1. Constipation
2. dizziness
3. drowsiness
4. dry mouth
5. increased appetite
6. weight gain

Less common

1. Abnormal dreams
2. back pain
3. dizziness or fainting when getting up suddenly from a lying or sitting position
4. increased need to urinate
5. increased sensitivity to touch
6. increased thirst
7. low blood pressure
8. muscle pain
9. nausea
10. sense of constant movement of self or surroundings
11. stomach pain
12. trembling or shaking
13. vomiting

Incidence not known

1. Painful or prolonged erection of the penis
2. swelling of the breasts or unusual milk production

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Portions of this document last updated: April 01, 2024

Original article: https://www.mayoclinic.org/drugs-supplements/mirtazapine-oral-route/side-effects/drg-20067334