Drug Monograph
Paroxetine (Paxil)
paroxetine hydrochloride
Pharmacokinetic Profile
Half-Life
~21 h (steady state)
Metabolism
CYP2D6 (saturable); hepatic oxidation & conjugation
Protein Binding
~95%
Bioavailability
~50% (saturable first-pass)
Volume of Distribution
3.1–28 L/kg (extensive)
Clinical Information
Drug Class
SSRI
Available Doses
10, 20, 30, 40 mg tablets
Route
Oral
Renal Adjustment
Yes — severe impairment
Hepatic Adjustment
Yes — severe impairment
Pregnancy
Risk of cardiac malformations (1st trimester); PPHN (3rd trimester)
Lactation
Present in breast milk; monitor infant
Schedule / Legal Status
Prescription only (not scheduled)
Generic Available
Yes
Black Box Warning
Suicidal thoughts & behaviors in young adults
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Major Depressive Disorder (MDD) | Adults | Monotherapy | FDA Approved |
| Obsessive Compulsive Disorder (OCD) | Adults | Monotherapy | FDA Approved |
| Panic Disorder (PD) | Adults | Monotherapy (with or without agoraphobia) | FDA Approved |
| Social Anxiety Disorder (SAD) | Adults | Monotherapy | FDA Approved |
| Generalized Anxiety Disorder (GAD) | Adults | Monotherapy | FDA Approved |
| Posttraumatic Stress Disorder (PTSD) | Adults | Monotherapy | FDA Approved |
Paroxetine is one of the most broadly indicated SSRIs, with FDA approval spanning six distinct psychiatric conditions in adults. It was the first SSRI approved for panic disorder and social anxiety disorder. Paroxetine is not approved for use in paediatric patients for any indication.
Off-Label Uses
Premature ejaculation: Paroxetine’s potent serotonin reuptake inhibition and high rate of ejaculatory delay make it the most frequently studied SSRI for this condition. Evidence quality: Moderate (multiple RCTs).
Vasomotor symptoms (menopause): A separate branded formulation (Brisdelle, 7.5 mg) is FDA-approved for this indication, but standard paroxetine is sometimes used off-label at higher doses. Evidence quality: High (RCTs).
Premenstrual Dysphoric Disorder (PMDD): The controlled-release formulation (Paxil CR) is approved for PMDD; immediate-release paroxetine is used off-label. Evidence quality: High.
Pruritus (chronic): Used in chronic pruritus associated with dermatological or systemic conditions. Evidence quality: Low (open-label studies, case series).
Dosing
Adult Dosing by Clinical Scenario
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Major depression — initial treatment | 20 mg once daily | 20–50 mg/day | 50 mg/day | Administer in the morning. Increase by 10 mg/day at intervals ≥1 week Screen for bipolar disorder before starting |
| OCD — moderate to severe | 20 mg once daily | 40–60 mg/day | 60 mg/day | Higher doses (40–60 mg) showed greater benefit than 20 mg in fixed-dose trials Allow 4–6 weeks for full response |
| Panic disorder — with or without agoraphobia | 10 mg once daily | 40 mg/day | 60 mg/day | Low starting dose to avoid initial worsening of panic symptoms Increase by 10 mg/day at ≥1 week intervals |
| Social anxiety disorder | 20 mg once daily | 20 mg/day | 60 mg/day | 20 mg/day is the recommended effective dose; no clear additional benefit above this in trials Can increase if needed at ≥1 week intervals |
| Generalized anxiety disorder | 20 mg once daily | 20 mg/day | 50 mg/day | Flat dose-response in trials; 20 mg/day usually sufficient Studied at 20–50 mg/day range |
| PTSD — adult | 20 mg once daily | 20–50 mg/day | 50 mg/day | Fixed-dose studies showed no clear benefit of 40 mg over 20 mg Increase by 10 mg/day at ≥1 week intervals |
Special Population Dosing
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Elderly patients (≥65 years) | 10 mg once daily | 10–40 mg/day | 40 mg/day | Reduced clearance; Cmin ~70–80% higher than younger adults Higher risk of hyponatraemia in this group |
| Severe renal impairment (CrCl <30 mL/min) | 10 mg once daily | 10–40 mg/day | 40 mg/day | Plasma concentrations ~4× higher than normal volunteers Titrate at extended intervals |
| Severe hepatic impairment | 10 mg once daily | 10–40 mg/day | 40 mg/day | ~2-fold increase in AUC and Cmax Titrate at extended intervals |
Clinical Pearl: Discontinuation Taper
Paroxetine has the highest discontinuation syndrome risk among SSRIs due to its short half-life and potent serotonin reuptake inhibition. Reduce dose gradually by 10 mg/day at weekly intervals. In GAD and PTSD trials, a taper schedule of 10 mg/day reductions per week followed by one week at 20 mg/day before stopping was used. If symptoms emerge on taper, consider reinstating the previous dose and tapering more slowly. Switching to fluoxetine (longer half-life) is sometimes used to facilitate discontinuation.
Pharmacology
Mechanism of Action
Paroxetine exerts its therapeutic effect by potently and selectively blocking the serotonin reuptake transporter (SERT) at presynaptic nerve terminals, increasing serotonergic neurotransmission in the central nervous system. Among the SSRIs, paroxetine has the highest binding affinity for SERT and is considered the most potent serotonin reuptake inhibitor in its class. It also exhibits weak affinity for muscarinic acetylcholine receptors, which contributes to its slightly higher rate of anticholinergic-type effects (dry mouth, constipation) compared with other SSRIs. Paroxetine has negligible activity at noradrenergic, dopaminergic, histaminergic, and other monoamine receptors at therapeutic concentrations. Notably, paroxetine is an irreversible inhibitor of CYP2D6, which has significant implications for drug interactions and for tamoxifen efficacy.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Complete oral absorption; bioavailability ~50% due to saturable first-pass metabolism; Tmax ~5.2 h at steady state; food increases Cmax by 29% but does not meaningfully alter overall exposure | Can be taken with or without food; once-daily dosing in the morning is recommended |
| Distribution | Vd 3.1–28 L/kg; ~95% protein-bound; only 1% remains in systemic circulation; distributes extensively into CNS | Highly lipophilic; extensive tissue distribution means plasma levels do not reflect tissue exposure |
| Metabolism | Hepatic via CYP2D6 (primary, saturable) and other CYP enzymes; metabolites are polar conjugates (glucuronide, sulphate) with ≤1/50 parent potency; nonlinear PK with increasing doses | CYP2D6 saturation causes disproportionate accumulation at higher doses; steady-state AUC ~8× single-dose prediction; potent CYP2D6 inhibitor (drug interaction risk) |
| Elimination | t½ ~21 h at steady state (CV 32%); 64% excreted renally (2% parent), 36% in faeces; steady state achieved in 7–14 days | Shorter half-life than fluoxetine or sertraline — contributes to higher discontinuation syndrome risk; dose-reduce in severe renal/hepatic impairment |
Side Effects
≥10%
Very Common
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Nausea | 26% | Most common GI effect; dose-dependent (14.7% at 10 mg rising to 36.3% at 40 mg in MDD trials); usually improves within 1–2 weeks |
| Somnolence | 23% | Dose-related; morning dosing helps; advise caution with driving until tolerance established |
| Dry mouth | 18% | Related to weak muscarinic activity; higher than most other SSRIs; dose-dependent |
| Headache | 18% | Similar to placebo rate (17%) in MDD trials; usually transient |
| Asthenia | 15% | Dose-dependent (2.9% at 10 mg, 12.7% at 40 mg); more prominent in SAD/OCD trials (22%) |
| Constipation | 14% | Dose-related; driven by anticholinergic properties |
| Dizziness | 13% | Dose-related; usually resolves; higher in panic disorder trials (14%) |
| Insomnia | 13% | Morning dosing recommended; may paradoxically improve as depression lifts |
| Ejaculatory disturbance (males) | 13–28% | Highest rate among SSRIs; dose-dependent; includes delayed ejaculation and anorgasmia; rate varies by indication (28% in SAD) |
| Diarrhoea | 12% | Serotonergic effect on GI tract; generally mild |
| Sweating | 11% | Dose-dependent; may persist long-term in some patients |
| Other male genital disorders | 10% | Includes erectile dysfunction, anorgasmia; dose-dependent |
1–10%
Common
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Tremor | 8% | Dose-dependent (0% at 10 mg, 14.7% at 40 mg); fine postural tremor; usually self-limiting |
| Decreased appetite | 6% | May lead to weight loss initially; some patients gain weight with chronic use |
| Nervousness | 5% | More common early in treatment; distinguish from initial jitteriness/akathisia |
| Anxiety | 5% | Dose-dependent; may indicate underlying activation |
| Blurred vision | 4% | Anticholinergic effect; dose-dependent (2.9% at 10 mg, 7.8% at 40 mg) |
| Paresthesia | 4% | Dose-dependent; also a prominent discontinuation symptom |
| Yawn | 4% | Serotonergic effect; benign |
| Palpitations | 3% | Generally benign; no clinically significant cardiac effects at therapeutic doses |
| Vasodilation (flushing) | 3% | More common in OCD trials (4%) |
| Urinary frequency | 3% | Generally self-limiting |
| Libido decreased (males) | 6–15% | Significant and may persist; important to discuss proactively |
| Libido decreased (females) | 0–9% | Often underreported; varies by indication |
| Female genital disorders | 2–9% | Includes anorgasmia, difficulty reaching climax; highest in PTSD and PD trials |
| Impotence (males) | 2–9% | Dose-dependent; highest in OCD trials (8%) |
| Rash | 2% | Typically mild; discontinue if severe or with systemic symptoms |
| Taste perversion | 2% | Usually self-limiting |
| Weight gain | Frequent | More prevalent with chronic use; among the SSRIs most associated with long-term weight gain |
Serious
Serious Adverse Effects (Regardless of Frequency)
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Suicidal thoughts/behaviours | 14 additional cases per 1,000 treated (<18 y); 5 per 1,000 (18–24 y) | First weeks to months | Close monitoring at initiation and dose changes; weekly visits initially; consider treatment change if persistent |
| Serotonin syndrome | Rare | Hours to days after initiation or dose increase, especially with co-serotonergic drugs | Immediate discontinuation of all serotonergic agents; supportive care; cyproheptadine may be used; hospital admission |
| Hyponatraemia (SIADH) | Uncommon; Na <110 mmol/L reported | Days to weeks; higher risk in elderly and those on diuretics | Check sodium if symptoms (confusion, falls, seizure); discontinue paroxetine; medical management of hyponatraemia |
| Seizures | 0.1% | Any time during treatment | Discontinue paroxetine; neurological evaluation |
| Mania/hypomania activation | ~1% (unipolar patients) | Days to weeks | Discontinue antidepressant; psychiatric reassessment; consider mood stabilizer |
| Abnormal bleeding (GI haemorrhage, ecchymoses) | Uncommon | Any time; risk increased with anticoagulants/NSAIDs | Assess bleeding source; consider discontinuation; monitor INR if on warfarin |
| Angle-closure glaucoma | Rare | Any time | Emergency ophthalmological referral; discontinue paroxetine |
| Stevens-Johnson syndrome / toxic epidermal necrolysis | Very rare (postmarketing) | Days to weeks | Immediate discontinuation; dermatology/burns unit referral |
| QT prolongation (in overdose or with pimozide/thioridazine) | Very rare at therapeutic doses | With concomitant QT-prolonging agents or overdose | Avoid contraindicated combinations; ECG monitoring in overdose |
| Hepatotoxicity (severe liver necrosis) | Very rare (postmarketing) | Variable | LFTs if symptoms; discontinue if transaminases markedly elevated |
Discontinuation
Discontinuation Rates
MDD Trials
20.0% discontinued due to adverse events
Top reasons: Nausea (3.2%), asthenia (1.6%), abnormal ejaculation (1.6%), somnolence (2.3%), sweating (1.0%), dry mouth (1.0%)
Anxiety Disorder Trials (range)
9.4–16.1% varied by indication
Highest: SAD (16.1%); Lowest: PD (9.4%). Top reasons: nausea, somnolence, asthenia, insomnia, abnormal ejaculation
| Reason for Discontinuation | Incidence (MDD) | Context |
|---|---|---|
| Nausea | 3.2% vs 1.1% placebo | Most frequent reason across all indications |
| Somnolence | 2.3% vs 0.7% placebo | Also a top reason in SAD (3.4%) and PTSD (2.8%) trials |
| Asthenia | 1.6% vs 0.4% placebo | Dose-related; prominent across anxiety disorder trials |
| Abnormal ejaculation | 1.6% vs 0% placebo | Highest in PD trials (4.9%); gender-corrected rates |
| Dizziness | — | Prominent in PD (1.5%) and SAD (1.9%) trials |
| Insomnia | — | Prominent in OCD (1.7%) and GAD (3.1%) trials |
Managing Sexual Dysfunction
Paroxetine carries the highest rate of sexual adverse effects among the SSRIs. Clinicians should proactively enquire about sexual function before initiation and at every follow-up, as patients rarely volunteer these complaints. Management options include dose reduction (if clinically feasible), switching to an SSRI with a lower rate of sexual side effects (e.g., bupropion augmentation or switching to bupropion, mirtazapine, or vortioxetine), or scheduling drug holidays (weekend breaks — though not recommended with paroxetine due to discontinuation risk). If sexual dysfunction persists and is distressing, a drug switch is generally the most effective strategy.
Drug Interactions
Paroxetine is a potent irreversible inhibitor of CYP2D6 and is itself metabolised primarily by CYP2D6 (saturable). This enzyme inhibition is the primary driver of clinically significant interactions. It has negligible effect on CYP3A4. Paroxetine is ~95% protein-bound, creating a theoretical displacement interaction risk with other highly protein-bound drugs.
Major
MAOIs (e.g., phenelzine, tranylcypromine, linezolid, IV methylene blue)
MechanismDual serotonergic enhancement
EffectRisk of serotonin syndrome (potentially fatal)
ManagementContraindicated. Allow ≥14 days washout between MAOI and paroxetine in either direction
FDA PI
Major
Thioridazine
MechanismCYP2D6 inhibition raises thioridazine levels
EffectQTc prolongation, risk of torsades de pointes and ventricular arrhythmias
ManagementContraindicated. Do not co-prescribe
FDA PI
Major
Pimozide
MechanismCYP2D6 inhibition raises pimozide levels
EffectQTc prolongation and cardiac arrhythmia risk
ManagementContraindicated. Do not co-prescribe
FDA PI
Major
Tamoxifen
MechanismIrreversible CYP2D6 inhibition blocks conversion of tamoxifen to active metabolite endoxifen
EffectReduced tamoxifen efficacy; may increase risk of breast cancer relapse
ManagementUse an alternative antidepressant with minimal CYP2D6 inhibition (e.g., venlafaxine, citalopram, escitalopram)
FDA PI
Moderate
Tricyclic Antidepressants (e.g., desipramine, nortriptyline)
MechanismCYP2D6 inhibition; desipramine AUC increased ~5-fold with paroxetine 20 mg/day
EffectTCA toxicity risk (QT prolongation, seizures, anticholinergic crisis)
ManagementReduce TCA dose substantially if combination is necessary; monitor TCA levels and ECG
FDA PI
Moderate
Warfarin
MechanismProtein-binding displacement and SSRI-mediated platelet dysfunction
EffectIncreased bleeding risk
ManagementMonitor INR closely; counsel patient on signs of bleeding
FDA PI
Moderate
Risperidone
MechanismCYP2D6 inhibition raises risperidone plasma levels ~4-fold
EffectIncreased risperidone exposure; risk of EPS and other dose-related side effects
ManagementReduce risperidone dose when adding paroxetine; monitor for adverse effects
FDA PI
Moderate
Metoprolol / Propranolol
MechanismCYP2D6 inhibition; these beta-blockers are CYP2D6 substrates
EffectIncreased beta-blocker levels; risk of bradycardia and hypotension (severe hypotension reported with metoprolol)
ManagementMonitor heart rate and blood pressure; consider dose adjustment of beta-blocker
FDA PI / Case report
Moderate
NSAIDs / Aspirin / Antiplatelet agents
MechanismSSRI-mediated serotonin depletion in platelets combined with antiplatelet effects
EffectIncreased risk of GI and other bleeding events
ManagementCounsel patients on bleeding signs; consider gastroprotection with PPI if ongoing NSAID needed
FDA PI
Moderate
Fosamprenavir / Ritonavir
MechanismReduced paroxetine plasma levels by mechanism not fully characterized
EffectPotential loss of antidepressant efficacy
ManagementAdjust paroxetine dose based on clinical response
FDA PI
Minor
Theophylline
MechanismElevated theophylline levels reported (not formally studied)
EffectPotential theophylline toxicity
ManagementMonitor theophylline levels during concurrent use
FDA PI
Minor
Digoxin
MechanismParoxetine showed no significant effect on digoxin PK in formal study
EffectNo clinically significant interaction expected
ManagementNo dose adjustment required; standard monitoring
FDA PIMonitoring
-
Mood & Suicidality
Weekly for first 4 weeks, then biweekly for 8 weeks, then at clinical discretion
Routine Assess for clinical worsening, suicidal ideation, unusual behavioural changes, especially in patients under 25. Use validated tools (PHQ-9, GAD-7, PCL-5 as appropriate) -
Sexual Function
Baseline, then each visit
Routine Enquire proactively about libido changes, ejaculatory/orgasmic function, and erectile function. Use ASEX or Arizona Sexual Experience Scale if available -
Weight
Baseline, then every 3 months
Routine Paroxetine is associated with more weight gain than most SSRIs with chronic use; monitor BMI and address early if trending upward -
Sodium (Na+)
Baseline in at-risk patients; recheck within 2–4 weeks
Trigger-based At-risk groups: elderly, patients on diuretics, volume-depleted. Check if confusion, falls, weakness, or seizures develop -
Hepatic Function
If symptoms arise (jaundice, dark urine, fatigue)
Trigger-based Severe hepatotoxicity is very rare but fatal cases reported; baseline LFTs reasonable in patients with hepatic disease -
Bleeding Signs
Each visit if on anticoagulants/NSAIDs
Trigger-based Ask about bruising, epistaxis, GI bleeding. Monitor INR if on warfarin -
Bone Health
Consider DEXA in long-term users with risk factors
Trigger-based Epidemiological data link SSRI use to increased fracture risk; ensure adequate calcium and vitamin D in elderly -
Discontinuation Symptoms
During and after any dose reduction
Routine Ask about dizziness, paresthesias, irritability, nausea, electric shock sensations (brain zaps), insomnia, and vivid dreams during taper
Contraindications & Cautions
Absolute Contraindications
- Concurrent MAOI use or use within 14 days of stopping an MAOI (including linezolid and intravenous methylene blue) — risk of serotonin syndrome
- Concurrent thioridazine — risk of QTc prolongation and ventricular arrhythmias
- Concurrent pimozide — risk of QTc prolongation
- Known hypersensitivity to paroxetine or any excipient (anaphylaxis, angioedema, Stevens-Johnson syndrome reported)
Relative Contraindications (Specialist Input Recommended)
- First trimester of pregnancy — less than 2-fold increase in cardiovascular malformations; initiate only after considering alternative treatments; shared decision-making with obstetrics
- Concurrent tamoxifen therapy for breast cancer treatment/prevention — paroxetine may reduce tamoxifen efficacy via CYP2D6 inhibition; use an alternative antidepressant
- Unstable bipolar disorder — risk of mania/hypomania activation; screen for bipolar features before initiation
- Active bleeding disorder or concurrent full-dose anticoagulation without adequate monitoring — increased bleeding risk
Use with Caution
- Seizure disorders — seizures occurred in 0.1% of treated patients; prescribe cautiously
- Anatomically narrow angles (untreated) — risk of angle-closure glaucoma; obtain ophthalmological assessment before starting
- Elderly patients — reduced clearance, higher risk of hyponatraemia and falls; start at 10 mg, maximum 40 mg
- Severe renal impairment (CrCl <30 mL/min) — plasma levels ~4× higher; start 10 mg, maximum 40 mg
- Severe hepatic impairment — ~2-fold increase in exposure; start 10 mg, maximum 40 mg
- Late pregnancy (third trimester) — risk of neonatal poor adaptation syndrome (respiratory distress, feeding difficulties, irritability) and possible PPHN
- Breastfeeding — present in breast milk; monitor infant for agitation, irritability, poor feeding
- Volume-depleted or diuretic-treated patients — increased risk of SIADH-related hyponatraemia
FDA Boxed Warning
Suicidal Thoughts and Behaviours
Antidepressants increased the risk of suicidal thinking and behaviour in paediatric and young adult patients in short-term studies. The risk is highest in those under 18 (14 additional cases per 1,000 treated) and in the 18–24 age group (5 additional cases per 1,000). Paroxetine is not approved for paediatric use. All patients started on antidepressant therapy should be closely monitored for clinical worsening and emergence of suicidal thoughts, especially during the initial months of treatment and at dose changes. Families and caregivers should be advised to observe for behavioural changes and to report concerns immediately.
Patient Counselling
Purpose of Therapy
Paroxetine works by increasing serotonin activity in the brain to improve symptoms of depression, anxiety, or the specific condition being treated. Full benefit typically takes 2–6 weeks, and it is important to continue taking it even after feeling better, unless your prescriber advises otherwise.
How to Take
Take paroxetine once daily in the morning with or without food. Swallow the tablet whole. If using the oral suspension, shake well before measuring a dose. Do not stop suddenly — always discuss tapering with your prescriber.
Nausea & Appetite Changes
Tell patientNausea is the most common early side effect and usually improves within 1–2 weeks. Taking the tablet with food may help. Some patients notice decreased appetite initially but may gain weight over time.
Call prescriberIf nausea is severe, persistent beyond 2 weeks, or accompanied by vomiting that prevents keeping fluids down.
Drowsiness & Dizziness
Tell patientDrowsiness affects about 1 in 4 patients and tends to improve over 2–4 weeks. Avoid driving or operating machinery until you know how paroxetine affects you.
Call prescriberIf drowsiness does not improve after 4 weeks or significantly interferes with daily functioning.
Sexual Side Effects
Tell patientChanges in sex drive, difficulty reaching orgasm, or (in men) delayed ejaculation are common with paroxetine and affect a substantial proportion of patients. These effects can begin early in treatment and may persist. Please discuss any concerns openly — strategies are available.
Call prescriberIf sexual side effects are distressing or affect your relationship — dose adjustments or alternative medications can be considered.
Never Stop Suddenly
Tell patientParoxetine must be tapered gradually under medical supervision. Stopping abruptly can cause withdrawal symptoms including dizziness, electric shock feelings, nausea, irritability, anxiety, insomnia, and vivid dreams. These are temporary but can be uncomfortable.
Call prescriberIf you accidentally miss several doses or run out of medication, or if withdrawal symptoms develop during a planned taper.
Mood Changes & Suicidality
Tell patientRarely, antidepressants may cause new or worsening thoughts of self-harm, particularly in the early weeks. Have a trusted person watch for mood changes, agitation, or unusual behaviour.
Call prescriberImmediately if new or worsening suicidal thoughts, agitation, irritability, or unusual behavioural changes occur. Go to the emergency department if there is immediate danger.
Pregnancy & Contraception
Tell patientParoxetine may increase the risk of heart defects in a developing baby if taken in the first trimester. If you are planning pregnancy, discuss alternatives with your prescriber before conception. Do not stop paroxetine abruptly if you discover you are pregnant.
Call prescriberAs soon as possible if you become pregnant or are planning pregnancy so treatment can be reviewed.
Bleeding Risk
Tell patientParoxetine may increase the tendency to bleed or bruise, especially if you also take aspirin, ibuprofen, or blood-thinning medications.
Call prescriberIf you notice unusual bruising, blood in stools, or prolonged bleeding from cuts.
Sources
Regulatory (PI / SmPC)
- PAXIL (paroxetine) tablets and oral suspension. Full Prescribing Information. Apotex Corp. Revised November 2024. FDA Label Primary regulatory source for all dosing, indications, adverse reaction incidence rates, contraindications, and pharmacokinetic data used in this monograph.
- DailyMed. PAXIL — paroxetine hydrochloride tablet, film coated. National Library of Medicine. Updated October 2024. DailyMed Structured product label with current NDC codes and packaging information.
- PAXIL CR (paroxetine hydrochloride) controlled-release tablets. Full Prescribing Information. Revised 2017. FDA Label (CR) Controlled-release formulation PI; used for cross-referencing PK differences and PMDD indication data.
Key Clinical Trials
- Dunner DL, Dunbar GC. Optimal dose regimen for paroxetine. J Clin Psychiatry. 1992;53 Suppl:21–26. Fixed-dose MDD trial establishing dose-response relationship and demonstrating dose-dependent adverse reactions at 10, 20, 30, and 40 mg.
- Wheadon DE, Bushnell WD, Steiner M. A fixed-dose comparison of 20, 40, and 60 mg paroxetine to placebo in the treatment of obsessive-compulsive disorder. Int Clin Psychopharmacol. 1993;8(4):237. Pivotal fixed-dose OCD study showing 40 mg and 60 mg superiority over 20 mg and placebo.
- Ballenger JC, Wheadon DE, Steiner M, Bushnell W, Gergel IP. Double-blind, fixed-dose, placebo-controlled study of paroxetine in the treatment of panic disorder. Am J Psychiatry. 1998;155(1):36–42. DOI Fixed-dose PD trial demonstrating paroxetine 40 mg efficacy; informed FDA approval for panic disorder.
- Stein MB, Liebowitz MR, Lydiard RB, et al. Paroxetine treatment of generalized social phobia (social anxiety disorder): a randomized controlled trial. JAMA. 1998;280(8):708–713. DOI Landmark RCT establishing paroxetine efficacy for social anxiety disorder.
Guidelines
- American Psychiatric Association. Practice Guideline for the Treatment of Patients with Major Depressive Disorder. 3rd ed. Washington, DC: APA; 2010. APA APA guideline positioning SSRIs including paroxetine as first-line treatment for MDD.
- National Institute for Health and Care Excellence (NICE). Depression in adults: treatment and management. NICE guideline NG222. 2022. NICE UK guideline on SSRI prescribing, monitoring, and discontinuation strategies.
- Bandelow B, Allgulander C, Baldwin DS, et al. World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for treatment of anxiety, obsessive-compulsive, and posttraumatic stress disorders — Version 3. Part I: Anxiety disorders. World J Biol Psychiatry. 2023;24(2):79–117. DOI International guideline recommending paroxetine for GAD, SAD, PD, and PTSD with evidence-level ratings.
Mechanistic / Basic Science
- Davis BA, Nagarajan A, Forrest LR, Singh SK. Mechanism of paroxetine (Paxil) inhibition of the serotonin transporter. Sci Rep. 2016;6:23789. DOI Elucidates the structural basis for paroxetine’s potent and selective SERT inhibition.
- Bourin M, Chue P, Guillon Y. Paroxetine: a review. CNS Drug Rev. 2001;7(1):25–47. DOI Comprehensive overview of paroxetine pharmacology including receptor binding profile and CYP2D6 inhibition.
Pharmacokinetics / Special Populations
- Kaye CM, Haddock RE, Langley PF, et al. A review of the metabolism and pharmacokinetics of paroxetine in man. Acta Psychiatr Scand. 1989;80(Suppl 350):60–75. DOI Foundational PK review establishing nonlinear kinetics, saturable first-pass metabolism, and steady-state parameters.
- Sindrup SH, Brøsen K, Gram LF. Pharmacokinetics of the selective serotonin reuptake inhibitor paroxetine: nonlinearity and relation to the sparteine oxidation polymorphism. Clin Pharmacol Ther. 1992;51(3):288–295. DOI Demonstrates CYP2D6 polymorphism impact on paroxetine pharmacokinetics and the basis for nonlinear dose-exposure relationships.
- Germann D, Ma G, Han F, Tikhomirova A. Paroxetine hydrochloride. Profiles of Drug Substances, Excipients and Related Methodology. 2013;38:367–406. DOI Detailed physicochemical characterisation and PK data review including volume of distribution and bioavailability across populations.