Summary

Commonly reported side effects of mirtazapine include: severe sedation, constipation, drowsiness, increased serum cholesterol, weight gain, fatigue, insomnia, increased appetite, xerostomia, and decreased appetite. Other side effects include: dizziness, increased serum triglycerides, tremor, dyspepsia, hot flash, palpitations, vertigo, abnormal dreams, bitter taste, decreased libido, and diaphoresis. Continue reading for a comprehensive list of adverse effects.

Applies to mirtazapine: oral tablets and orally disintegrating tablets.

Side effects include:

Somnolence, increased appetite, weight gain, dizziness.

For Healthcare Professionals

Applies to mirtazapine: oral tablet, oral tablet disintegrating.

Nervous system

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]