Remeron Side Effects

Generic name: mirtazapine

Medically reviewed by Drugs.com. Last updated on Apr 21, 2025.

Note: This document provides detailed information about Remeron Side Effects associated with mirtazapine. Some dosage forms listed on this page may not apply specifically to the brand name Remeron.

Applies to mirtazapine: oral tablet, oral tablet disintegrating.

Important warnings This medicine can cause some serious health issues

Oral route (tablet; tablet, disintegrating)

Suicidal Thoughts and Behaviors. Increased risk of suicidal thoughts and behavior in pediatric and young adult patients taking antidepressants.

Closely monitor all antidepressant-treated patients for clinical worsening and emergence of suicidal thoughts and behaviors.

Mirtazapine is not approved for use in pediatric patients.

Common side effects of Remeron

Some side effects of mirtazapine 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 side effects

• constipation
• dizziness
• drowsiness
• dry mouth
• increased appetite
• weight gain

Less common side effects

• abnormal dreams
• back pain
• dizziness or fainting when getting up suddenly from a lying or sitting position
• increased need to urinate
• increased sensitivity to touch
• increased thirst
• low blood pressure
• muscle pain
• nausea
• sense of constant movement of self or surroundings
• stomach pain
• trembling or shaking
• vomiting

Incidence not known

• painful or prolonged erection of the penis
• swelling of the breasts or unusual milk production

Serious side effects of Remeron

Along with its needed effects, mirtazapine (the active ingredient contained in Remeron) 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 while taking mirtazapine:

Less common side effects

• decreased or increased movement
• mood or mental changes, including abnormal thinking, agitation, anxiety, confusion, and feelings of not caring
• skin rash
• swelling
• trouble breathing

Rare side effects

• change in menstrual cycle (periods)
• chills
• decreased sexual ability
• fever
• menstrual pain
• mood or mental changes, including anger, feelings of being outside the body, mood swings, and unusual excitement
• mouth sores
• seeing, hearing, or feeling things that are not there
• seizures
• sore throat

Incidence not known

• black, tarry stools
• blistering, peeling, loosening of skin
• chest pain
• fainting
• hives, itching, skin rash
• irregular or slow heart rate
• joint or muscle pain
• painful or difficult urination
• red, irritated eyes
• red skin lesions, often with a purple center
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swollen glands
• unusual bleeding or bruising
• unusual tiredness or weakness

For healthcare professionals

Applies to mirtazapine: oral tablet, oral tablet disintegrating.

Nervous system adverse events

• Very common (10% or more): Somnolence (up to 54%)
• Common (1% to 10%): Dizziness, tremor, headache, sedation/drowsiness
• Uncommon (0.1% to 1%): Hypesthesia, hypokinesia, vertigo, amnesia, hyperkinesia, paresthesia, lethargy
• Rare (0.01% to 0.1%): Syncope, migraine, ataxia, dyskinesia, extrapyramidal syndrome, coordination abnormal, dysarthria, dystonia, reflexes increased, restless legs, akathisia (psychomotor restlessness)
• Very rare (less than 0.01%): Vascular headache, cerebral ischemia, aphasia, nystagmus, stupor, dementia, paralysis, grand mal convulsion, hypotonia, taste loss, myoclonus, parosmia
• Frequency not reported: Hypertonia, taste perversion, convulsions (insults)
• Postmarketing reports: Impaired concentration, cerebrovascular disorder, movement disorders^[Ref]

Gastrointestinal

• Very common (10% or more): Dry mouth (up to 25%), constipation (up to 13%)
• Common (1% to 10%): Nausea
• Uncommon (0.1% to 1%): Abdominal pain, abdominal syndrome acute, vomiting, diarrhea
• Rare (0.01% to 0.1%): Abdomen enlarged, eructation, glossitis, nausea and vomiting, gum hemorrhage, stomatitis, colitis, oral hypoesthesia
• Very rare (less than 0.01%): Tongue discoloration, ulcerative stomatitis, salivary gland enlargement, increased salivation, intestinal obstruction, pancreatitis, aphthous stomatitis, gastritis, gastroenteritis, oral moniliasis, tongue edema
• Frequency not reported: Dyspepsia, flatulence, oral paresthesia, mouth edema^[Ref]

Metabolic

• Very common (10% or more): Increased appetite (up to 17%), weight gain (up to 12%)
• Uncommon (0.1% to 1%): Anorexia
• Rare (0.01% to 0.1%): Dehydration, weight loss
• Very rare (less than 0.01%): Gout, acid phosphatase increased, diabetes mellitus, hyponatremia
• Frequency not reported: Hypertriglyceridemia
• Postmarketing reports: Hypercholesterolemia, hyperlipidemia^[Ref]

Psychiatric

• Common (1% to 10%): Abnormal dreams, thinking abnormal, confusion
• Uncommon (0.1% to 1%): Apathy, depression, agitation, anxiety, insomnia
• Rare (0.01% to 0.1%): Delirium, delusions, depersonalization, increased libido, hallucinations, manic reaction/mania, neurosis, hostility, emotional lability, euphoria, paranoid reaction, nightmares/vivid dreams
• Very rare (less than 0.01%): Drug dependence, psychotic depression, withdrawal syndrome, serotonin syndrome, aggression
• Frequency not reported: Nervousness, decreased libido, suicidal ideation, suicidal behavior, somnambulism
• Postmarketing reports: Psychomotor restlessness, drug withdrawal symptoms, paroniria^[Ref]

Cardiovascular

• Common (1% to 10%): Peripheral edema, edema
• Uncommon (0.1% to 1%): Hypertension, vasodilation, orthostatic hypotension
• Rare (0.01% to 0.1%): Angina pectoris, myocardial infarction, bradycardia, ventricular extrasystoles, hypotension
• Very rare (less than 0.01%): Chest pain substernal, atrial arrhythmia, bigeminy, cardiomegaly, phlebitis, left heart failure
• Frequency not reported: Chest pain, palpitation, tachycardia, postural hypotension, ECG changes
• Postmarketing reports: Ventricular arrhythmia, Torsades de pointes, generalized edema, localized edema^[Ref]

There was a mean increase in heart rate observed in patients given this drug compared to placebo (3.4 bpm versus 0.8 bpm, respectively); however, the clinical significance of this difference is unknown.^[Ref]

Musculoskeletal

• Common (1% to 10%): Back pain, myalgia
• Uncommon (0.1% to 1%): Myasthenia, arthralgia, twitching
• Rare (0.01% to 0.1%): Neck rigidity, neck pain, arthritis, tenosynovitis
• Very rare (less than 0.01%): Pathologic fracture, osteoporosis fracture, bone pain, myositis, tendon rupture, arthrosis, bursitis
• Postmarketing reports: Increased creatine kinase blood levels, rhabdomyolysis^[Ref]

Respiratory

• Common (1% to 10%): Dyspnea
• Uncommon (0.1% to 1%): Cough increased, sinusitis
• Rare (0.01% to 0.1%): Epistaxis, bronchitis, asthma, pneumonia
• Very rare (less than 0.01%): Respiratory/pulmonary embolus, asphyxia, laryngitis, pneumothorax, hiccup
• Frequency not reported: Pharyngitis, rhinitis
• Postmarketing reports: Pulmonary embolism^[Ref]

Genitourinary

• Common (1% to 10%): Urinary frequency
• Uncommon (0.1% to 1%): Urinary tract infection
• Rare (0.01% to 0.1%): Dysuria, urinary incontinence, urinary retention, vaginitis, hematuria, breast pain, amenorrhea, dysmenorrhea, leukorrhea, impotence
• Very rare (less than 0.01%): Polyuria, urethritis, metrorrhagia, abnormal ejaculation, breast engorgement, breast enlargement, urinary urgency, menorrhagia^[Ref]

Other

• Common (1% to 10%): Asthenia
• Uncommon (0.1% to 1%): Malaise, thirst, fatigue
• Rare (0.01% to 0.1%): Chills, fever, face edema, ulcer, ear pain, deafness, hyperacusis
• Very rare (less than 0.01%): Healing abnormal, partial transitory deafness, otitis media
• Frequency not reported: Pain, tinnitus^[Ref]

Immunologic

• Common (1% to 10%): Influenza/flu syndrome
• Frequency not reported: Infection^[Ref]

Dermatologic

• Uncommon (0.1% to 1%): Pruritus, rash, exanthema
• Rare (0.01% to 0.1%): Photosensitivity reaction, acne, exfoliative dermatitis, dry skin, herpes simplex, alopecia
• Very rare (less than 0.01%): Cellulitis, petechia, urticaria, herpes zoster, skin hypertrophy, skin ulcer, seborrhea
• Frequency not reported: Sweating
• Postmarketing reports: Stevens-Johnson Syndrome, bullous dermatitis, erythema multiforme, toxic epidermal necrolysis, rash (including erythematous and maculopapular)^[Ref]

Ocular

• Rare (0.01% to 0.1%): Eye pain, abnormality of accommodation, conjunctivitis, keratoconjunctivitis, lacrimation disorder, angle-closure glaucoma
• Very rare (less than 0.01%): Diplopia, blepharitis
• Frequency not reported: Amblyopia
• Postmarketing reports: Glaucoma^[Ref]

Hepatic

• Rare (0.01% to 0.1%): Cholecystitis, liver function tests abnormal
• Very rare (less than 0.01%): Cirrhosis of the liver, AST increased, ALT increased
• Postmarketing reports: Jaundice, hepatitis^[Ref]

Renal

• Rare (0.01% to 0.1%): Kidney calculus, cystitis^[Ref]

Hematologic

• Very rare (less than 0.01%): Lymphadenopathy, leukopenia, anemia, thrombocytopenia, lymphocytosis, pancytopenia
• Frequency not reported: Bone marrow depression (granulocytopenia, agranulocytosis, aplastic anemia, thrombocytopenia), eosinophilia
• Postmarketing reports: Thromboembolic disorder, coagulation disorder^[Ref]

Endocrine

• Very rare (less than 0.01%): Goiter, hypothyroidism
• Frequency not reported: Inappropriate antidiuretic hormone secretion^[Ref]

Frequently asked questions

• Does Remeron help with sleep?

Further information

Remeron side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer