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Fluoxetine Side Effects

The most commonly reported side effects of fluoxetine include fatigue, nausea, and headache, based on 132,763 FDA adverse event reports from 2004 to 2025. 5.1% of reports found the drug to be ineffective.

Fluoxetine side effects

Percentages show how often each reaction appears relative to total reports for fluoxetine.

1
Drug Ineffective5.1%6,815
2
Fatigue4.9%6,440
3
Nausea4.4%5,901
4
Headache4.0%5,286
5
Off Label Use3.8%4,989
6
Anxiety3.4%4,516
7
Diarrhoea3.3%4,374
8
Depression3.3%4,365
9
Toxicity To Various Agents3.2%4,226
10
Dizziness3.1%4,133
11
Drug Interaction3.0%4,044
12
Pain3.0%3,980
13
Vomiting2.8%3,725
14
Dyspnoea2.7%3,646
15
Fall2.7%3,584

These are voluntary reports and do not establish that fluoxetine caused these reactions.

Report severity

71.7%Serious95,220 reports
31.1%Hospitalizations41,301 reports
10.4%Fatal13,795 reports

Seriousness is determined by the reporter, not by OpenClaim.

Fluoxetine drug interactions

Other drugs that appear in adverse event reports alongside fluoxetine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Quetiapine-fumarate4.2%5,574
2
Sodium-oxybate3.5%4,594
3
Adalimumab3.3%4,445
4
Olanzapine3.0%4,044
5
Aripiprazole2.8%3,748
6
Acetaminophen2.5%3,352
7
Bupropion2.3%2,992
8
Omeprazole2.1%2,843
9
Sertraline-hydrochloride2.1%2,835
10
Venlafaxine2.0%2,658
11
Gabapentin1.9%2,562
12
Alprazolam1.9%2,510
13
Pregabalin1.8%2,343
14
Duloxetine-hydrochloride1.7%2,193
15
Lamotrigine1.6%2,161

Taken alongside

1
Acetaminophen11.8%15,686
2
Omeprazole9.6%12,726
3
Levothyroxine-sodium9.6%12,723
4
Ergocalciferol9.0%11,895
5
Aspirin8.7%11,582
6
Gabapentin8.3%11,051
7
Albuterol7.5%9,896
8
Atorvastatin-calcium7.2%9,583
9
Lisinopril6.1%8,058
10
Alprazolam5.9%7,854
11
Metformin5.7%7,561
12
Clonazepam5.7%7,533
13
Furosemide5.6%7,424
14
Amlodipine5.4%7,139
15
Fluticasone5.3%7,057

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports fluoxetine side effects

65.6% of fluoxetine adverse event reports involve female patients and 26.3% involve male patients. The largest age group is adult at 70%. These figures reflect who reports side effects, not underlying risk.

Sex

Female65.6%
Male26.3%
Unknown8.1%

Age group

< 21.3%
2–111.3%
12–176.1%
18–6469.8%
65+21.5%

What is fluoxetine used for

Conditions and purposes for which patients were taking fluoxetine when the adverse event was reported.

Abdominal DiscomfortAbdominal PainAbdominal Pain UpperAbnormal BehaviourAbnormal DreamsAbortion SpontaneousAccidental ExposureAccidental OverdoseAccidental PoisoningAcneActivities Of Daily Living ImpairedAcute Flaccid MyelitisAcute PsychosisAcute Stress DisorderAdjustment Disorder

Showing 15 of 1,004 indications

Fluoxetine brand names and reporting trend

Fluoxetine is sold under the brand name Prozac.

Brand names

Prozac882

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking fluoxetine with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.