Adverse effects by incidence[2][3][4][5]
Legend
† serious—either life-threatening in the short-term (matter of days or less) or are usually irreversible
‡ potentially (though not usually) irreversible
# most often transient
* may indicate, or lead to, life-threatening or irreversible conditions if persisting into the long-term
Very common (>10% incidence) adverse effects include:
Headache#
Nausea#
Insomnia# (sleeplessness)
appetite loss. This may be a desirable effect in obese patients but in children, the underweight, the pregnant and in those affected by the eating disorder, anorexia nervosa, this may be an undesirable effect.
Anxiety#
Asthenia# (weakness)
Diarrhea#
Nervousness#
Somnolence# (drowsiness)
Common (1-10% incidence) adverse effects include:
Dizziness#
Dry mouth* (can lead to dental caries if left uncontrolled)
Dyspepsia (indigestion)
Tremor#
Decreased libido‡
Dysgeusia (abnormal taste)
Agitation#
QTc interval prolongation†
Chest pain
Chills#
Confusion
Ear pain
Hypertension* (high blood pressure)
Increased appetite
Restlessness#
Tension#
Abnormal/blurred vision#
Flushing#
Yawning
Rash
Urticaria (hives)
Pruritus (itchiness)
Hyperhidrosis (excess sweating)
Abnormal dreams (including nightmares)
Palpitation
Sleep disorder
Tinnitus (hearing ringing in the ears)
Urinary frequency
Vomiting#
Weight gain or loss
Arthralgia (joint pain)
Gynaecological bleeding
Erectile dysfunction‡ (impotence)
Ejaculation disorder‡
Feeling jittery#
Twitching#
Epistaxis (nose bleed; only common in children and adolescents treated with fluoxetine)
Uncommon (0.1-1% incidence) adverse effects include:
Depersonalization
Elevated mood
Euphoric mood
Abnormal thoughts
Abnormality in or difficulty achieving an orgasm‡ (anorgasmia)
Bruxism* (teeth grinding)
Dyskinesia (a movement disorder characterized by either a lack of voluntary movement or the presence of involuntary movements)
Ataxia
Balance disorder
Akathisia/psychomotor restlessness[36][37][note 2]
Mania† (a dangerously elated/irritable mood)
Buccoglossal syndrome[note 3]
Seizures†
Myoclonus (spasmodic, jerky movement of muscle groups)
Mydriasis (dilation of the pupils)
Hypotension (low blood pressure)
Dyspnea (air hunger)
Dysphagia (difficulty/discomfort from swallowing)
Alopecia (hair loss)
Increased tendency to bruise/ecchymosis
Cold sweat
Malaise
Feeling abnormal
Feeling hot or cold
Dysuria (painful or difficult urination)
Rare (0.01-0.1% incidence) adverse effects include:
Anaphylactic reaction†
Serum sickness
Hyponatremia† (low blood sodium)
Hallucinations†
Agitation
Panic attacks
Vasculitis
Pharyngitis
Esophageal pain
Angioedema
Photosensitivity reaction
Purpura
Urinary retention† (being unable to pass urine)
Galactorrhea (lactation that is unrelated to pregnancy or breastfeeding)
Priapism† (a persistent and painful erection)
Very rare (<0.01% incidence) adverse effects include:
Thrombocytopaenia† (a drop in platelet count leading to an increased risk of bleeds)
Serotonin syndrome†
Orthostatic hypotension (a drop in blood pressure that occurs when one stands up)
Unknown frequency adverse effects include:
Syndrome of inappropriate secretion of antidiuretic hormone† (SIADH)
Suicidal thoughts and/or behavior†
Dysphemia (stuttering)
Memory impairment
Pulmonary events
Gastrointestinal hemorrhage† (bleeding into the digestive tract)
Hepatitis† (inflammation [swelling] of the liver)
Erythema multiforme† (a potentially fatal skin reaction)
Myalgia (muscle ache)
Micturition disorder (problems with urination)
Mucosal hemorrhage†
Dystonia[37][40][41]
Tardive dyskinesia†[37][40][41] (an often irreversible movement disorder)
Abnormal liver function tests