What the label lists and what reports show
Fluoxetine side effects
Fluoxetine's FDA label: “Most common adverse reactions (≥5% and at least twice that for placebo) associated with: Major Depressive Disorder, Obsessive Compulsive Disorder, Bulimia, and Panic Disorder: abnormal dreams, abnormal ejaculation, anorexia, anxiety, asthenia, diarrhea, dry …” FAERS holds 131,827 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is nausea (7,747 reports).
- Generic listed
- Boxed warning
Check it at the source: the fluoxetine FDA label on DailyMed (effective January 8, 2026, Dista Products Company); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of PROZAC?PROZAC may cause serious side effects, including: See “What is the most important information I should know about PROZAC?” Problems with blood sugar control. People who have diabetes and take PROZAC may have problems with low blood sugar while taking PROZAC. High blood sugar can happen when PROZAC is stopped. Your healthcare provider may need to change the dose of your diabetes medicines when you start or stop taking PROZAC. […]
Source: FDA drug label, NDA018936 (Eli Lilly And Co), as published by Dista Products Company, effective January 8, 2026 (SPL set c88f33ed-6dfb-4c5e-bc01-d8e36dd97299), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥5% and at least twice that for placebo) associated with: Major Depressive Disorder, Obsessive Compulsive Disorder, Bulimia, and Panic Disorder: abnormal dreams, abnormal ejaculation, anorexia, anxiety, asthenia, diarrhea, dry mouth, dyspepsia, flu syndrome, impotence, insomnia, libido decreased, nausea, nervousness, pharyngitis, rash, sinusitis, somnolence, sweating, tremor, vasodilatation, and yawn […]
Table 3: Treatment-Emergent Adverse Reactions: Incidence in Major Depressive Disorder, OCD, Bulimia and Panic Disorder Placebo-Controlled Clinical Trials Incidence less than 1%. , Includes US data for Major Depressive…
This table is printed in the Fluoxetine hydrochloride label published by Upsher-Smith Laboratories, LLC of October 6, 2023; the label quoted above does not print one.
| Body System/ Adverse Reaction | Fluoxetine (N=2,869) | Placebo (N=1,673) |
|---|---|---|
| Headache | 21 | 19 |
| Asthenia | 11 | 6 |
| Flu syndrome | 5 | 4 |
| Fever | 2 | 1 |
| Vasodilatation | 2 | 1 |
| Nausea | 22 | 9 |
| Diarrhea | 11 | 7 |
| Anorexia | 10 | 3 |
| Dry mouth | 9 | 6 |
| Dyspepsia | 8 | 4 |
| Constipation | 5 | 4 |
| Flatulence | 3 | 2 |
| Vomiting | 3 | 2 |
| Weight loss | 2 | 1 |
| Insomnia | 19 | 10 |
| Nervousness | 13 | 8 |
| Anxiety | 12 | 6 |
| Somnolence | 12 | 5 |
| Dizziness | 9 | 6 |
| Tremor | 9 | 2 |
| Libido decreased | 4 | 1 |
| Thinking abnormal | 2 | 1 |
| Sweating | 7 | 3 |
| Rash | 4 | 3 |
| Pruritus | 3 | 2 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following adverse reactions are discussed in more detail in other sections of the labeling: Suicidal Thoughts and Behaviors in Children, Adolescents, and Young Adults [see Boxed Warning and Warnings and Precautions ( 5.1 )] Serotonin Syndrome [see Warnings and Precautions ( 5.2 )] Allergic Reactions and Rash [see Warnings and Precautions ( 5.3 )] Screening Patients for Bipolar Disorder and Monitoring for Mania/Hypomania [see Warnings and Precautions ( 5.4 )] Seizures [see Warnings and Precautions ( 5.5 )] Altered Appetite and Weight [see Warnings and Precautions ( 5.6 )] Increased Risk of Bleeding [see Warnings and Precautions ( 5.7 )] Angle-Closure Glaucoma [see Warnings and Precautions ( 5.8 )] Hyponatremia [see Warnings and Precautions ( 5.9 )] Anxiety and Insomnia [see Warnings and Precautions ( 5.10 )] QT Prolongation [see Warnings and Precautions ( 5.11 )] Potential for Cognitive and Motor Impairment [see Warnings and Precautions ( 5.13 )] Discontinuation Adverse Reactions [see Warnings and Precautions ( 5.15 )] Sexual Dysfunction [see Warnings and Precautions ( 5.17 )] When using PROZAC and olanzapine in combination, also refer to the Adverse Reactions section of the package insert for Symbyax.
Source: FDA drug label, NDA018936 (Eli Lilly And Co), as published by Dista Products Company, effective January 8, 2026 (SPL set c88f33ed-6dfb-4c5e-bc01-d8e36dd97299), via openFDA; the full label on DailyMed
What do FAERS reports show?
131,827 reports list fluoxetine among the medicines taken, each a report of something that happened, not proof the medicine caused it; 13,381 are coded as a death and 40,996 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 18 reactions below, 11 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Fluoxetine: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions