Prozac Side Effects

Generic Name: fluoxetine

Note: This page contains side effects data for the generic drug fluoxetine. It is possible that some of the dosage forms included below may not apply to the brand name Prozac.

It is possible that some side effects of Prozac may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to fluoxetine: oral capsule, oral capsule delayed release, oral solution, oral syrup, oral tablet

As well as its needed effects, fluoxetine (the active ingredient contained in Prozac) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking fluoxetine, check with your doctor immediately:

More common
  • Hives
  • inability to sit still
  • itching
  • restlessness
  • skin rash
Less common
  • Chills or fever
  • joint or muscle pain
  • Anxiety
  • cold sweats
  • confusion
  • convulsions (seizures)
  • cool pale skin
  • diarrhea
  • difficulty with concentration
  • drowsiness
  • dryness of the mouth
  • excessive hunger
  • fast or irregular heartbeat
  • headache
  • increased sweating
  • increased thirst
  • lack of energy
  • mood or behavior changes
  • overactive reflexes
  • purple or red spots on the skin
  • racing heartbeat
  • shakiness or unsteady walk
  • shivering or shaking
  • talking, feeling, and acting with excitement and activity you cannot control
  • trouble with breathing
  • unusual or incomplete body or facial movements
  • unusual tiredness or weakness
Incidence not known
  • Abdominal or stomach pain
  • agitation
  • back or leg pains
  • bleeding gums
  • blindness
  • blistering, peeling, or loosening of the skin
  • bloating
  • blood in the urine or stools
  • bloody, black, or tarry stools
  • blue-yellow color blindness
  • blurred vision
  • chest pain or discomfort
  • clay-colored stools
  • constipation
  • continuing vomiting
  • cough or dry cough
  • dark urine
  • decreased urine output
  • decreased vision
  • depression
  • difficulty with breathing
  • difficulty with swallowing
  • dizziness or lightheadedness
  • eye pain
  • fainting
  • fast, pounding, or irregular heartbeat or pulse
  • general body swelling
  • high fever
  • hives, itching, puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • hostility
  • indigestion
  • irregular or slow heart rate
  • irritability
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • loss of appetite
  • loss of bladder control
  • muscle twitching
  • nausea
  • nightmares
  • noisy breathing
  • nosebleeds
  • pain in the ankles or knees
  • painful, red lumps under the skin, mostly on the legs
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pinpoint red spots on the skin
  • rapid weight gain
  • red or irritated eyes
  • red skin lesions, often with a purple center
  • redness, tenderness, itching, burning, or peeling of the skin
  • severe muscle stiffness
  • severe sleepiness
  • slurred speech
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • stopping of heart
  • sudden shortness of breath or troubled breathing
  • sudden weakness in the arms or legs
  • sudden, severe chest pain
  • swelling of the face, ankles, or hands
  • swollen or painful glands
  • thoughts of killing oneself
  • tightness in the chest
  • tiredness
  • twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
  • unconsciousness
  • unpleasant breath odor
  • unusual bleeding or bruising
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  • unusually pale skin
  • use of extreme physical or emotional force
  • vomiting of blood
  • yellow eyes or skin

Some fluoxetine side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Decreased appetite
Less common or rare
  • Abnormal dreams
  • breast enlargement or pain
  • change in sense of taste
  • changes in vision
  • feeling of warmth or heat
  • flushing or redness of the skin, especially on face and neck
  • frequent urination
  • hair loss
  • increased appetite
  • increased sensitivity of the skin to sunlight
  • menstrual pain
  • stomach cramps, gas, or pain
  • unusual secretion of milk, in females
  • weight loss
  • yawning
Incidence not known
  • Cracks in the skin
  • loss of heat from the body
  • painful or prolonged erections of the penis
  • scaly skin
  • swelling of the breasts or breast soreness in both females and males
  • unusual milk production

For Healthcare Professionals

Applies to fluoxetine: compounding powder, oral capsule, oral delayed release capsule, oral solution, oral tablet


The most common side effects that have been associated with the discontinuation of placebo-controlled clinical trials were anxiety, nervousness, nausea, rash, pruritus, insomnia, asthenia, and headache.

The side effect profile appears generally similar between adults, children, and adolescents. Treatment-emergent side effects reported in pediatric patients that were reported at an incidence of at least 2% or more for fluoxetine (the active ingredient contained in Prozac) and greater than placebo included thirst, hyperkinesia, agitation, personality disorder, epistaxis, urinary frequency, and menorrhagia. The most common side effect associated with treatment discontinuation in children and adolescents was mania/hypomania.


Antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. An increased risk of suicidal thinking and behavior in children, adolescents, and young adults (aged 18 to 24 years) with major depressive disorder (MDD) and other psychiatric disorders has been reported with short-term use of antidepressant drugs.

Adult and pediatric patients receiving antidepressants for MDD, as well as for psychiatric and nonpsychiatric indications, have reported symptoms that may be precursors to emerging suicidality, including anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia, hypomania, and mania. Causality has not been established.

Very common (10% or more): Anxiety, insomnia, nervousness, somnolence
Common (1% to 10%): Abnormal dreams, disturbance in attention, emotional lability, feeling abnormal, restlessness, sleep disorder, tension, thinking abnormal
Uncommon (0.1% to 1%): Akathisia, apathy, depersonalization, elevated mood, euphoria, hostility, intentional overdose, manic reaction, neurosis, paranoid reaction, personality disorder, psychomotor hyperactivity, psychosis, suicide attempt
Rare (less than 0.1%): Agitation, antisocial reaction, delusions, dysarthria, hallucinations, hypomania, intentional injury, mania, panic attacks, stupor
Frequency not reported: Dysphemia, suicidal thoughts and behavior
Postmarketing reports: Confusion, violent behaviors

Nervous system

Very common (10% or more): Dizziness, headache, tremor
Common (1% to 10%): Amnesia, paresthesia
Uncommon (0.1% to 1%): Abnormal gait, acute brain syndrome, ataxia, balance disorder, CNS depression, CNS stimulation, dyskinesia, hyperkinesia, hypesthesia, hypertonia, incoordination, migraine, myoclonus, neuralgia, neuropathy, seizures, syncope, vascular headache, vertigo
Rare (less than 0.1%): Abnormal EEG, cerebral embolism, cerebral ischemia, circumoral paresthesia, convulsion, decreased reflexes, dystonia, extrapyramidal syndrome, foot drop, hyperesthesia, neuritis, paralysis
Postmarketing reports: Cerebrovascular accident, memory impairment, movement disorders, oculogyric crisis, tardive dyskinesia

One retrospective study of 23 outpatients with Parkinson's disease treated with 40 mg of fluoxetine a day reported that three patients experienced worsening of parkinsonism, two patients experienced improvement of parkinsonism, and 18 patients experienced no change. Another small study reported a series of four patients who experienced worsening of parkinsonism during treatment with fluoxetine.

A number of case reports have implicated fluoxetine in causing seizures. Twelve of 6000 patients experienced convulsions during pre-marketing testing.

A case of dose-dependent exacerbation of preexisting, mild restless legs syndrome (which ultimately required discontinuation of fluoxetine) has been reported.


One placebo-controlled study has suggested that fluoxetine (the active ingredient contained in Prozac) has no effects on intraventricular conduction. Other case reports have suggested that fluoxetine may rarely provoke dysrhythmias. Other conflicting case reports have suggested that fluoxetine may have a propensity to provoke and alleviate vasoconstriction. Several cases of unexpected death occurring shortly after initiation of fluoxetine therapy have been reported in elderly patients with multiple medical problems.

In one case report, QTc prolongation and torsades de pointes developed in an elderly woman 6 months after starting therapy with fluoxetine 20 mg daily. The QTc interval returned to normal following discontinuation of fluoxetine. Four additional cases suggesting fluoxetine associated QTc prolongation or torsades de pointes have been reported.

Common (1% to 10%): Chest pain, flushing, hypertension, palpitations, vasodilatation
Uncommon (0.1% to 1%): Angina pectoris, arrhythmia, congestive heart failure, generalized edema, hypotension, myocardial infarct, peripheral edema, postural hypotension
Rare (less than 0.1%): Bradycardia, extrasystoles, heart block, pallor, peripheral vascular disorder, phlebitis, shock, thrombophlebitis, thrombosis, vasculitis, vasospasm, ventricular extrasystoles, ventricular fibrillation
Postmarketing reports: Atrial fibrillation, heart arrest, QT-interval prolongation and ventricular arrhythmia including torsades de pointes


A study of 26,005 antidepressant users has reported 3.6 times more upper GI bleeding episodes with the use of SSRIs relative to the population who did not receive antidepressant medications. Upper gastrointestinal tract bleeding was observed in 3.9 times more frequently in patients receiving fluoxetine (the active ingredient contained in Prozac)

Very common (10% or more): Anorexia, diarrhea, dry mouth, nausea
Common (1% to 10%): Abdominal pain, constipation, dyspepsia, flatulence, increased appetite, taste perversion, vomiting
Uncommon (0.1% to 1%): Aphthous stomatitis, bruxism, buccoglossal syndrome, cholelithiasis, colitis, dysphagia, eructation, esophagitis, gastritis, gastroenteritis, glossitis, gum hemorrhage, hyperchlorhydria, increased salivation, melena, mouth ulcerations, stomach ulcer, stomatitis, thirst
Rare (less than 0.1%): Acute abdominal syndrome, biliary pain, Bloody diarrhea, cholecystitis, duodenal ulcer, enteritis, esophageal pain, esophageal ulcer, fecal incontinence, gastrointestinal hemorrhage, hematemesis, intestinal obstruction, pancreatitis, peptic ulcer, salivary gland enlargement, stomach ulcer hemorrhage, taste loss, tongue edema
Postmarketing reports: Gastrointestinal bleeding


Numerous cases of hyponatremia have been reported following treatment with an SSRI. Risk factors for the development of SSRI associated hyponatremia including advanced age, female gender, concomitant use of diuretics, low body weight, and lower baseline serum sodium levels have been identified. Hyponatremia tends to develop within the first few weeks of treatment (range 3 to 120 days) and typically resolves within 2 weeks (range 48 hours to 6 weeks) after therapy has been discontinued with some patients requiring treatment. The proposed mechanism for the development of hyponatremia involves the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) via release of antidiuretic hormone.

Decreased weight gain has been observed in association with the use of fluoxetine (the active ingredient contained in Prozac) in children and adolescent patients.

Common (1% to 10%): Weight loss
Uncommon (0.1% to 1%): Decreased appetite, dehydration, gout, hypocholesteremia, hyperlipemia, hypokalemia
Rare (less than 0.1%): Alcohol intolerance, creatine phosphokinase increased, diabetes mellitus, hyperkalemia, hyperuricemia, hypocalcemia, hyponatremia
Postmarketing reports: Hypoglycemia, inappropriate secretion of antidiuretic hormone


Very common (10% or more): Fatigue (including asthenia)
Common (1% to 10%): Accidental injury, chills, ear pain, feeling jittery, fever, infection, pain, tinnitus
Uncommon (0.1% to 1%): Feeling hot/cold, malaise
Rare (less than 0.1%): Deafness, hyperacusis, hypothermia
Very rare (less than 0.01%): Serotonin syndrome (neuroleptic malignant syndrome-like effects)
Frequency not reported: Mucosal hemorrhage
Postmarketing reports: Malignant hyperthermia

Potentially life-threatening serotonin syndrome has been reported with SSRIs and SNRIs as monotherapy, but particularly with concomitant use of other serotonergic drugs and drugs that impair the metabolism of serotonin.


Common (1% to 10%): Decreased libido, ejaculation disorder, erectile dysfunction, gynecological bleeding, impotence, urinary frequency
Uncommon (0.1% to 1%): Abortion, albuminuria, amenorrhea, anorgasmia, breast enlargement, breast pain, cystitis, dysuria, female lactation, fibrocystic breast, hematuria, impaired urination, Increased libido, leukorrhea, menorrhagia, metrorrhagia, nocturia, pelvic pain, polyuria, sexual dysfunction (occasionally persisting after treatment discontinuation), urinary incontinence, urinary retention, urinary urgency, vaginal hemorrhage
Rare (less than 0.1%): Breast engorgement, galactorrhea, glycosuria, hyperprolactinemia, hypomenorrhea, priapism, uterine fibroids, uterine hemorrhage
Postmarketing reports: Enlarged clitoris, gynecomastia, vaginal bleeding

Urinary retention and galactorrhea have been reported with other SSRIs.

The estimates of the incidence of untoward sexual experience and performance may underestimate their actual incidence, partly because patients and physicians may be reluctant to discuss this issue. In placebo-controlled clinical trials ejaculation disorder (primarily ejaculation delay) was reported as a treatment-emergent side effect at an incidence of 6% and at least twice the incidence in placebo-treated male patients.


Common (1% to 10%): Pruritus, rash, sweating, urticaria
Uncommon (0.1% to 1%): Acne, alopecia, cold sweat, contact dermatitis, ecchymosis, eczema, increased tendency to bruise, maculopapular rash, skin discoloration, skin ulcer
Rare (less than 0.1%): Furunculosis, hirsutism, petechia, photosensitivity reaction, psoriasis, purpura, purpuric rash, seborrhea
Postmarketing reports: Epidermal necrolysis, erythema multiforme, erythema nodosum, exfoliative dermatitis, Stevens Johnson syndrome, thrombocytopenic purpura

Approximately 3% of treated patients have been reported to develop a skin reaction.


Uncommon (0.1% to 1%): Hypothyroidism
Rare (less than 0.1%): Diabetic acidosis, hyperprolactinemia


Uncommon (0.1% to 1%): Anemia
Rare (less than 0.1%): Blood dyscrasia, hypochromic anemia, leukopenia, lymphedema, lymphocytosis, thrombocythemia, iron deficiency anemia
Very rare (less than 0.01%): Thrombocytopenia
Postmarketing reports: Aplastic anemia, immune-related hemolytic anemia, pancytopenia, eosinophilia


Uncommon (0.1% to 1%): Abnormal liver function tests
Rare (less than 0.1%): Alkaline phosphatase increased, hepatitis, liver fatty deposit, SGPT increased
Postmarketing reports: Aggravation of hepatic damage, cholestatic jaundice, hepatic failure/necrosis, idiosyncratic hepatitis


Common (1% to 10%): Allergic reaction
Uncommon (0.1% to 1%): Face edema
Rare (less than 0.1%): Anaphylactoid reaction, angioedema, serum sickness


Common (1% to 10%): Flu syndrome
Uncommon (0.1% to 1%): Herpes zoster


Epidemiological studies, primarily in patients aged 50 years or older, have shown an increased risk of bone fractures in patients receiving SSRIs or TCAs.

Common (1% to 10%): Arthralgia, twitching
Uncommon (0.1% to 1%): Arthritis, bone pain, bursitis, leg cramps, tenosynovitis
Rare (less than 0.1%): Arthrosis, chondrodystrophy, myasthenia, myopathy, myositis, osteomyelitis, osteoporosis, rheumatoid arthritis
Frequency not reported: Myalgia


Common (1% to 10%): Abnormal vision, vision blurred
Uncommon (0.1% to 1%): Conjunctivitis, dry eyes, mydriasis, photophobia
Rare (less than 0.1%): Blepharitis, diplopia, exophthalmos, glaucoma, iritis, scleritis, strabismus, visual field defect
Postmarketing reports: Cataract, optic neuritis


Rare (less than 0.1%): BUN increased, kidney pain, oliguria
Postmarketing reports: Kidney failure


Very common (10% or more): Pharyngitis, rhinitis
Common (1% to 10%): Epistaxis, yawn
Uncommon (0.1% to 1%): Asthma, dyspnea, hiccup, hyperventilation
Rare (less than 0.1%): Apnea, atelectasis, decreased cough, emphysema, hemoptysis, hypoventilation, hypoxia, larynx edema, lung edema, parosmia, pneumothorax, stridor,
Frequency not reported: pulmonary events (inflammatory processes of varying histopathology and/or fibrosis)
Postmarketing reports: Eosinophilic pneumonia, pulmonary embolism, pulmonary hypertension

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