Fluoxetine HCL side effects: what 5,342 FDA adverse event reports show
Drug class
Not stated in label
Who reports
5,342 reports · 65% serious · 483 with death outcome · 70% female
Used for
Fluoxetine capsules are indicated for the treatment of: • Acute and maintenance treatment of Major Depressive Disorder [ see Clinical Studies (14.1)]. • Acute and maintenance treatment of obsessions and compulsions in patients with Obsessive Compulsive Disorder (OCD) [ see Clinical Studies (14.2 )].
What it is
Fluoxetine capsules, USP are a selective serotonin reuptake inhibitor for oral administration. It is designated (±)-N-methyl-3-phenyl-3-[(α,α,α-trifluoro-p-tolyl) oxy] propylamine hydrochloride and has the empirical formula of C 17 H 18 F 3 NO•HCl.
Boxed warning
SUICIDAL THOUGHTS AND BEHAVIORS • Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term studies. These studies did not show an increase in the r.
Causality screen of the 40 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Outcome field, not a reaction Death is a report outcome, not a reaction term. It is dominated by the underlying illness; see the seriousness profile and the boxed warning instead.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 350 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Sleep apnoea syndrome | 92 | 19.0 15.5–23.2ROR 19.3 · χ² 1,542 / p <1e-300 | 18.8 EB05 15.8 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 19.3 | no trial data cached |
| Serotonin syndrome | 65 | 13.4 10.5–17.1ROR 13.5 · χ² 731 / p 3e-161 | 13.2 EB05 10.6 · IC025 +3.2 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 11.6 · 90% clinician | no trial data cached |
| Drug exposure during pregnancy | 71 | 8.1 6.4–10.2ROR 8.2 · χ² 434 / p 9e-97 | 7.8 EB05 6.3 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious PRR 7.9 · 92% clinician | no trial data cached |
| Akathisia (inner restlessness) | 27 | 7.8 5.3–11.3ROR 7.8 · χ² 153 / p 2e-35 | 7.0 EB05 5.0 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.7 · ♀ 41% (drug 70%) | no trial data cached |
| Drug toxicity | 26 | 7.4 5.0–10.9ROR 7.4 · χ² 137 / p 5e-32 | 6.7 EB05 4.7 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 6.8 · ♀ 48% (drug 70%) | no trial data cached |
| Economic problem | 29 | 7.4 5.1–10.6ROR 7.4 · χ² 154 / p 1e-35 | 6.7 EB05 4.9 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 6.1 | no trial data cached |
| Bipolar disorder | 20 | 7.2 4.6–11.1ROR 7.2 · χ² 100 / p 7e-24 | 6.3 EB05 4.3 · IC025 +1.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 7.2 | no trial data cached |
| Mania | 29 | 6.9 4.8–10.0ROR 7.0 · χ² 141 / p 7e-33 | 6.3 EB05 4.6 · IC025 +2.0 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 7.3 | no trial data cached |
| Paranoia | 30 | 6.8 4.8–9.7ROR 6.8 · χ² 143 / p 3e-33 | 6.2 EB05 4.5 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 7.0 · ♀ 41% (drug 70%) | no trial data cached |
| Intervertebral disc degeneration | 15 | 6.3 3.8–10.5ROR 6.4 · χ² 62 / p 2e-15 | 5.4 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Suicidal ideation (thoughts of suicide) | 147 | 6.3 5.4–7.4ROR 6.5 · χ² 653 / p 3e-144 | 6.2 EB05 5.4 · IC025 +2.4 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.7 | no trial data cached |
| Back injury | 16 | 5.8 3.6–9.5ROR 5.8 · χ² 59 / p 8e-15 | 5.0 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Suicide attempt | 86 | 5.6 4.5–6.9ROR 5.6 · χ² 318 / p 2e-71 | 5.4 EB05 4.5 · IC025 +2.1 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 4.9 | no trial data cached |
| Completed suicide (death by suicide) | 113 | 5.3 4.4–6.3ROR 5.4 · χ² 389 / p 8e-87 | 5.2 EB05 4.4 · IC025 +2.1 3/3 methods agree | Outcome field, not a reaction | serious PRR 4.6 · 93% clinician | no trial data cached |
| Hallucination, auditory | 21 | 5.2 3.4–8.0ROR 5.2 · χ² 67 / p 2e-16 | 4.7 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Restless legs syndrome | 24 | 5.2 3.5–7.7ROR 5.2 · χ² 77 / p 9e-19 | 4.7 EB05 3.4 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Pulmonary congestion | 17 | 5.0 3.1–8.1ROR 5.1 · χ² 51 / p 4e-13 | 4.5 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.9 | no trial data cached |
| Nightmare | 44 | 5.0 3.7–6.7ROR 5.0 · χ² 136 / p 1e-31 | 4.7 EB05 3.7 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 | no trial data cached |
| Mydriasis | 16 | 4.9 3.0–8.0ROR 4.9 · χ² 46 / p 6e-12 | 4.3 EB05 2.8 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.6 | no trial data cached |
| Micturition urgency | 14 | 4.9 2.9–8.2ROR 4.9 · χ² 39 / p 2e-10 | 4.2 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Therapeutic response unexpected | 55 | 4.8 3.7–6.2ROR 4.8 · χ² 162 / p 2e-37 | 4.6 EB05 3.7 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 6.6 | no trial data cached |
| Activities of daily living impaired | 24 | 4.7 3.1–7.0ROR 4.7 · χ² 66 / p 2e-16 | 4.3 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.0 | no trial data cached |
| Panic attack | 43 | 4.6 3.4–6.2ROR 4.7 · χ² 119 / p 5e-28 | 4.4 EB05 3.4 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.8 | no trial data cached |
| Aggression | 59 | 4.6 3.6–6.0ROR 4.7 · χ² 164 / p 7e-38 | 4.5 EB05 3.6 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.7 | no trial data cached |
| Euphoric mood | 12 | 4.6 2.6–8.1ROR 4.6 · χ² 30 / p 2e-8 | 4.0 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Depression | 262 | 4.5 4.0–5.1ROR 4.7 · χ² 718 / p 2e-158 | 4.5 EB05 4.0 · IC025 +2.0 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 4.1 | no trial data cached |
| Respiratory arrest | 31 | 4.4 3.1–6.2ROR 4.4 · χ² 78 / p 7e-19 | 4.1 EB05 3.1 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.9 · 100% clinician | no trial data cached |
| Intervertebral disc protrusion | 23 | 4.1 2.7–6.2ROR 4.1 · χ² 51 / p 4e-13 | 3.8 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Type 2 diabetes mellitus | 35 | 4.1 2.9–5.7ROR 4.1 · χ² 78 / p 5e-19 | 3.9 EB05 2.9 · IC025 +1.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.7 | no trial data cached |
| Ankle fracture | 16 | 4.1 2.5–6.6ROR 4.1 · χ² 34 / p 3e-9 | 3.7 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Restlessness | 37 | 4.0 2.9–5.5ROR 4.0 · χ² 79 / p 3e-19 | 3.8 EB05 2.9 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.5 | no trial data cached |
| Coordination abnormal | 14 | 3.9 2.3–6.6ROR 3.9 · χ² 28 / p 8e-8 | 3.5 EB05 2.3 · IC025 +0.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.7 | no trial data cached |
| Fibromyalgia | 24 | 3.9 2.6–5.8ROR 3.9 · χ² 49 / p 2e-12 | 3.6 EB05 2.6 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 2.6 · ♀ 100% (drug 70%) | no trial data cached |
| Psychotic disorder | 29 | 3.9 2.7–5.5ROR 3.9 · χ² 59 / p 1e-14 | 3.7 EB05 2.7 · IC025 +1.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.2 | no trial data cached |
| Mood swings | 31 | 3.8 2.7–5.4ROR 3.8 · χ² 62 / p 2e-15 | 3.6 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Anger | 33 | 3.8 2.7–5.4ROR 3.8 · χ² 66 / p 2e-16 | 3.6 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Hepatic steatosis | 18 | 3.8 2.4–6.0ROR 3.8 · χ² 34 / p 2e-9 | 3.5 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 | no trial data cached |
| Emotional disorder | 30 | 3.8 2.7–5.4ROR 3.8 · χ² 59 / p 7e-15 | 3.6 EB05 2.7 · IC025 +1.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.3 | no trial data cached |
| Blood sodium decreased | 18 | 3.8 2.4–6.0ROR 3.8 · χ² 34 / p 3e-9 | 3.5 EB05 2.3 · IC025 +1.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.5 | no trial data cached |
| Poisoning | 12 | 3.7 2.1–6.6ROR 3.7 · χ² 21 / p 2e-6 | 3.3 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Depression | 262 | 4.5 4.0–5.1ROR 4.7 · χ² 718 / p 2e-158 | 4.5 EB05 4.0 · IC025 +2.0 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 4.1 | no trial data cached |
| Anxiety | 229 | 3.2 2.8–3.6ROR 3.3 · χ² 339 / p 5e-76 | 3.1 EB05 2.8 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.2 | no trial data cached |
| Fall | 204 | 2.4 2.1–2.8ROR 2.5 · χ² 170 / p 5e-39 | 2.4 EB05 2.1 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.1 | no trial data cached |
| Insomnia (trouble sleeping) | 157 | 2.3 2.0–2.7ROR 2.4 · χ² 117 / p 1e-27 | 2.3 EB05 2.0 · IC025 +0.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.4 | no trial data cached |
| Suicidal ideation (thoughts of suicide) | 147 | 6.3 5.4–7.4ROR 6.5 · χ² 653 / p 3e-144 | 6.2 EB05 5.4 · IC025 +2.4 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.7 | no trial data cached |
| Feeling abnormal | 142 | 2.3 2.0–2.7ROR 2.4 · χ² 106 / p 3e-25 | 2.3 EB05 2.0 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Somnolence (drowsiness) | 137 | 2.7 2.3–3.2ROR 2.7 · χ² 144 / p 2e-33 | 2.7 EB05 2.3 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.6 | no trial data cached |
| Drug interaction | 127 | 3.1 2.6–3.7ROR 3.2 · χ² 185 / p 2e-42 | 3.1 EB05 2.7 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | serious PRR 2.9 | no trial data cached |
| Weight increased (weight gain) | 116 | 2.0 1.7–2.4ROR 2.1 · χ² 62 / p 2e-15 | 2.0 EB05 1.7 · IC025 +0.7 | Labeled (related wording) related wording | serious PRR 2.4 | no trial data cached |
| Tremor (shaking) | 115 | 2.7 2.3–3.3ROR 2.8 · χ² 124 / p 4e-29 | 2.7 EB05 2.3 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.0 | no trial data cached |
| Completed suicide (death by suicide) | 113 | 5.3 4.4–6.3ROR 5.4 · χ² 389 / p 8e-87 | 5.2 EB05 4.4 · IC025 +2.1 3/3 methods agree | Outcome field, not a reaction | serious PRR 4.6 · 93% clinician | no trial data cached |
| Confusional state (confusion) | 99 | 2.4 2.0–2.9ROR 2.4 · χ² 80 / p 2e-19 | 2.4 EB05 2.0 · IC025 +0.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.3 | no trial data cached |
| Memory impairment | 95 | 2.7 2.2–3.3ROR 2.7 · χ² 102 / p 3e-24 | 2.7 EB05 2.3 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.9 | no trial data cached |
| Sleep apnoea syndrome | 92 | 19.0 15.5–23.2ROR 19.3 · χ² 1,542 / p <1e-300 | 18.8 EB05 15.8 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 19.3 | no trial data cached |
| Muscle spasms | 89 | 1.9 1.5–2.3ROR 1.9 · χ² 38 / p 4e-10 | 1.9 EB05 1.6 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.0 | no trial data cached |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Sleep apnoea syndrome — n=92, PRR 19.0
- Drug toxicity — n=26, PRR 7.4
- Paranoia — n=30, PRR 6.8
- Hallucination, auditory — n=21, PRR 5.2
- Restless legs syndrome — n=24, PRR 5.2
- Nightmare — n=44, PRR 5.0
- Activities of daily living impaired — n=24, PRR 4.7
- Intervertebral disc protrusion — n=23, PRR 4.1
- Fibromyalgia — n=24, PRR 3.9
- Mood swings — n=31, PRR 3.8
✓ A hand-written Bradford Hill causality assessment exists for this drug: Fluoxetine ↔ Serotonin syndrome.
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Fluoxetine?
In FDA FAERS, the most frequently co-reported reaction terms for Fluoxetine are depression, anxiety, fall, insomnia, suicidal ideation, feeling abnormal. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Fluoxetine have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: SUICIDAL THOUGHTS AND BEHAVIORS • Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term studies. These studies did not show an increase in the r.
Do FAERS signals prove that Fluoxetine causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 05b0781b-50e2-4311-bde0-430b96e2ef8e, effective 20240712; matched on
openfda.generic_name.exact:"FLUOXETINE") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 390 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.