Fluoxetine chemical structure (SSRI), 2D skeletal formula, C17H18F3NO

Fluoxetine Chemical Structure

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1. Identification

Summary

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) indicated for major depressive disorder, obsessive–compulsive disorder, bulimia nervosa, panic disorder, and premenstrual dysphoric disorder; pediatric indications include MDD and OCD.

Brand Names

Prozac, Sarafem; multiple generics

Name

Fluoxetine

Background

Racemic SSRI introduced in the late 1980s; marketed commonly as the hydrochloride salt for oral capsules/tablets/solutions; active metabolite norfluoxetine contributes to prolonged effect.

Modality

Small molecule

Groups

Approved; prescription

Structure

Fluoxetine chemical structure (SSRI), 2D skeletal formula, C17H18F3NO
Fluoxetine chemical structure (SSRI), 2D skeletal formula, C17H18F3NO

Weight

~309.33 g/mol (base)

Chemical Formula

C₁₇H₁₈F₃NO (base)

Synonyms

N-methyl-3-phenyl-3-[4-(trifluoromethyl)phenoxy]propan-1-amine; fluoxetine free base; fluoxetine hydrochloride (salt)

External IDs

CAS (base): 54910-89-3; CAS (HCl): 56296-78-7
PubChem CID (base): 3386
UNII (base): 01K63SUP8D; UNII (HCl): I9W7N6B1KJ
ATC: N06AB03

2. Pharmacology

Indication

MDD, OCD, bulimia nervosa, panic disorder, PMDD; pediatric MDD/OCD per labeling.

Associated Conditions

Anxiety disorders, treatment-resistant depression when used in fixed combination with olanzapine (region-specific).

Associated Therapies

Monotherapy; fixed-dose olanzapine/fluoxetine for bipolar depression or TRD (jurisdiction-dependent).

Contraindications & Blackbox Warnings

Boxed warning: antidepressants ↑ risk of suicidal thoughts/behaviors in children, adolescents, young adults.
Contraindicated with MAOIs (including linezolid and IV methylene blue), pimozide, thioridazine. Allow adequate washout intervals.

Pharmacodynamics

Potent SERT inhibition → ↑ synaptic serotonin; minimal direct NET/DAT inhibition at therapeutic exposure; active norfluoxetine maintains SERT blockade.

Mechanism of action

Reversible blockade of presynaptic serotonin transporter; downstream receptor adaptations drive clinical response.

Absorption

Oral bioavailability ~60–80%; tₘₐₓ ~6–8 h; food effect not clinically significant.

Volume of distribution

Extensive tissue distribution; crosses placenta and appears in breast milk.

Protein binding

~94–95% (albumin, α₁-acid glycoprotein).

Metabolism

Hepatic CYP2D6 (major) → norfluoxetine (active); both inhibit CYP2D6.

Route of elimination

Primarily urinary (~80%) and fecal (~15%) as metabolites/parent.

Half-life

Fluoxetine: ~1–3 days (acute), ~4–6 days (chronic).
Norfluoxetine: ~8–10 days on average; longer ranges reported.

Clearance

Hepatic clearance with auto-inhibition over time; renal function has limited effect on total exposure.

Adverse Effects

Nausea, insomnia, anxiety, headache, sexual dysfunction; hyponatremia/SIADH (elderly risk), QT prolongation (caution with risk factors), bleeding with anticoagulants/antiplatelets/NSAIDs, mania/hypomania in bipolar disorder.

Toxicity

Overdose usually benign to moderate; monitor for serotonin toxicity, QT effects, and seizures.

Pathways

SERT inhibition; CYP2D6 biotransformation; biliary/renal handling of metabolites.

Pharmacogenomic Effects/ADRs

CYP2D6 poor metabolizers: ↑ exposure and longer persistence; consider interaction-driven phenoconversion (CYP2D6 inhibition of co-meds).

3. Interactions

Drug Interactions

Absolute: MAOIs (including linezolid/IV methylene blue), pimozide, thioridazine.
Major: other serotonergic agents (risk of serotonin syndrome); CYP2D6 substrates with narrow TI (e.g., thioridazine, pimozide, TCAs); tamoxifen (↓ endoxifen due to CYP2D6 inhibition); warfarin/antiplatelets/NSAIDs (↑ bleeding risk); QT-prolonging drugs.

Food Interactions

No clinically meaningful food effect; dose consistently.

4. Categories

ATC Codes

N06AB03 (SSRIs)

Drug Categories

Antidepressant; SSRI; Small molecule

Chemical Taxonomy

Diphenylpropylamine aryl ether with para-trifluoromethyl substituent; tertiary amine

Affected organisms

Humans (therapeutic use)

5. Chemical Identifiers

UNII

01K63SUP8D (fluoxetine, base)

CAS number

54910-89-3 (base); 56296-78-7 (hydrochloride)

InChI Key

RTHCYVBBDHJXIQ-UHFFFAOYSA-N (base)

InChI

InChI=1S/C17H18F3NO/c1-21-12-11-16(13-5-3-2-4-6-13)22-15-9-7-14(8-10-15)17(18,19)20/h2-10,16,21H,11-12H2,1H3

IUPAC Name

N-methyl-3-phenyl-3-[4-(trifluoromethyl)phenoxy]propan-1-amine

SMILES

CNCCC(c1ccccc1)Oc2ccc(cc2)C(F)(F)F

6. References

PubChem — formula C₁₇H₁₈F₃NO, MW 309.33 g/mol, identifiers (CID 3386); IUPAC/SMILES. PubChem
NIST WebBook — Standard InChI for fluoxetine base; formula and mass. NIST WebBook
FDA GSRS/UNII — fluoxetine base 01K63SUP8D; fluoxetine HCl I9W7N6B1KJ, salt InChIKey GIYXAJPCNFJEHY-UHFFFAOYSA-N. gsrs.ncats.nih.gov+1
ATC/DDD Index — N06AB03 classification and DDD. atcddd.fhi.no
DailyMed — long half-lives of fluoxetine and norfluoxetine; persistence after discontinuation; PK ranges. DailyMed+2DailyMed+2
DrugBank/clinical PK summaries — half-life ranges (parent 1–3/4–6 days; norfluoxetine 4–16 days); interaction framework. DrugBank
Wikipedia (consolidated pharmacokinetic table with primary citations) — bioavailability 60–80%, protein binding 94–95%, urine 80%/feces 15%. Wikipedia

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