Paroxetine
JFDA label: Unirox
- Suicidality and antidepressant drugs:
Mechanism of Action
Paroxetine is a selective serotonin reuptake inhibitor, chemically unrelated to tricyclic, tetracyclic, or other antidepressants; presumably, the inhibition of serotonin reuptake from brain synapse stimulated serotonin activity in the brain
Indications
Approved
- Generalized anxiety disorder (immediate release)
- Major depressive disorder (immediate and controlled release)
- Obsessive-compulsive disorder (immediate release)
- Panic disorder (immediate and controlled release)
- Post-traumatic stress disorder (immediate release)
- Premenstrual dysphoric disorder (controlled release)
- Social anxiety disorder (immediate and controlled release)
- Vasomotor symptoms of menopause (Brisdelle only)
Off-label
- Obsessive-compulsive disorder (children and adolescents)
- Social anxiety disorder (children and adolescents)
Contraindications
Source: Lexicomp
- Concurrent use with or within 14 days of MAOIs intended to treat psychiatric disorders Absolute
- concomitant use with pimozide or thioridazine Absolute
- hypersensitivity to paroxetine or any of its inactive ingredients Absolute
- initiation in patients being treated with linezolid or methylene blue IV Absolute
- pregnancy (Brisdelle only) Absolute
Adverse Reactions
Cardiac disorders (5)
Common chest pain · hypertension · palpitations · tachycardia · Vasodilatation
Nervous system disorders (22)
Very Common Discontinuation syndrome (high risk) · dizziness · Drowsiness · headache · insomnia · Somnolence
Common abnormal dreams · agitation · amnesia · anxiety · chills · confusion · depersonalization · emotional lability · fatigue · lack of concentration · myasthenia · myoclonus · Nervousness · paresthesia · vertigo · yawning
Renal and urinary disorders (8)
Very Common Ejaculatory disorder
Common dysmenorrhea · female genital tract disease · impotence · Male genital disease · orgasm disturbance · urinary frequency · urinary tract infection
Metabolism and nutrition disorders (4)
Very Common Decreased libido
Common Weight gain · Weight gain
Rare Hyponatraemia (SIADH)
Gastrointestinal disorders (15)
Very Common Constipation · constipation · diarrhea · Dry mouth · Nausea · Nausea · xerostomia
Common abdominal pain · Decreased appetite · dysgeusia · dyspepsia · flatulence · increased appetite · nausea and vomiting · vomiting
Skin and subcutaneous tissue disorders (3)
Very Common Diaphoresis
Common pruritus · Skin rash
Musculoskeletal and connective tissue disorders (6)
Very Common tremor · Weakness
Common arthralgia · back pain · Myalgia · myopathy
Eye disorders (2)
Common Blurred vision · visual disturbance
Ear and labyrinth disorders (1)
Common Tinnitus
Reproductive system and breast disorders (1)
Very Common Sexual dysfunction
Infections and infestations (1)
Common Infection
Respiratory, thoracic and mediastinal disorders (4)
Common Dyspnea · pharyngitis · rhinitis · sinusitis
Dosing
Source: Lexicomp
Warnings & Precautions
Source: Lexicomp
Suicidal thinking/behavior
Antidepressants increase the risk of suicidal thinking and behavior in children, adolescents, and young adults (18 to 24 years of age) with major depressive disorder (MDD) and other psychiatric disorders; consider risk prior to prescribing. Short-term studies did not show an increased risk in patients >24 years of age and showed a decreased risk in patients ≥65 years. Closely monitor patients for clinical worsening, suicidality, or unusual changes in behavior, particularly during the initial 1 to 2 months of therapy or during periods of dosage adjustments (increases or decreases); the patient's family or caregiver should be instructed to closely observe the patient and communicate condition with healthcare provider. A medication guide concerning the use of antidepressants should be dispensed with each prescription. Paroxetine is not FDA approved for use in children.
Akathisia
Inability to remain still due to feelings of agitation or restlessness has been observed with paroxetine and other SSRIs. Usually occurs within the first few weeks of therapy.
Anticholinergic effects
Has low potential for sedation and anticholinergic effects relative to cyclic antidepressants; however among the SSRI class these effects are relatively higher.
Bleeding risk
May impair platelet aggregation resulting in increased risk of bleeding events, particularly if used concomitantly with aspirin, NSAIDs, warfarin or other anticoagulants. Bleeding related to SSRI use has been reported to range from relatively minor bruising and epistaxis to life-threatening hemorrhage.
CNS depression
May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving).
Fractures
Bone fractures have been associated with antidepressant treatment. Consider the possibility of a fragility fracture if an antidepressant-treated patient presents with unexplained bone pain, point tenderness, swelling, or bruising (Rabenda 2013; Rizzoli, 2012).
Ocular effects
May cause mild pupillary dilation, which can lead to an episode of narrow-angle glaucoma in susceptible individuals. Consider evaluating patients who have not had an iridectomy for narrow-angle glaucoma risk factors.
Serotonin syndrome
Potentially life-threatening serotonin syndrome (SS) has occurred with serotonergic agents (eg, SSRIs, SNRIs), particularly when used in combination with other serotonergic agents (eg, triptans, TCAs, fentanyl, lithium, tramadol, buspirone, St John's wort, tryptophan) or agents that impair metabolism of serotonin (eg, MAO inhibitors intended to treat psychiatric disorders, other MAO inhibitors [ie, linezolid and intravenous methylene blue]). Monitor patients closely for signs of SS such as mental status changes (eg, agitation, hallucinations, delirium, coma); autonomic instability (eg, tachycardia, labile blood pressure, diaphoresis); neuromuscular changes (eg, tremor, rigidity, myoclonus); GI symptoms (eg, nausea, vomiting, diarrhea); and/or seizures. Discontinue treatment (and any concomitant serotonergic agent) immediately if signs/symptoms arise.
Sexual dysfunction
May cause or exacerbate sexual dysfunction.
SIADH and hyponatremia
SSRIs and SNRIs have been associated with the development of SIADH; hyponatremia has been reported rarely (including severe cases with serum sodium Disease-related concerns:
Cardiovascular disease
Use with caution in patients with cardiovascular disease; paroxetine has not been systemically evaluated in patients with a recent history of MI or unstable heart disease.
Hepatic impairment
Use with caution in patients with hepatic impairment; clearance is decreased and plasma concentrations are increased; a lower dosage may be needed.
Mania/hypomania
May worsen psychosis in some patients or precipitate a shift to mania or hypomania in patients with bipolar disorder. Monotherapy in patients with bipolar disorder should be avoided. Patients presenting with depressive symptoms should be screened for bipolar disorder. Paroxetine is not FDA approved for the treatment of bipolar depression.
Renal impairment
Use with caution in patients with renal impairment; clearance is decreased and plasma concentrations are increased; a lower dosage may be needed.
Seizure disorder
Use with caution in patients with a previous seizure disorder or condition predisposing to seizures such as brain damage or alcoholism. Concurrent drug therapy issues:
Drug-drug interactions
Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Dosage form specific issues:
Brisdelle
Brisdelle contains a lower dose than what is required for the treatment of psychiatric conditions. Patients who require paroxetine for the treatment of psychiatric conditions should discontinue Brisdelle and begin treatment with a paroxetine-containing medication which provides an adequate dosage.
Polysorbate 80
Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson 2002; Lucente 2000; Shelley, 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade 1986; CDC 1984). See manufacturer's labeling. Other warnings/precautions:
Discontinuation syndrome
Abrupt discontinuation or interruption of antidepressant therapy has been associated with a discontinuation syndrome. Symptoms arising may vary with antidepressant however commonly include nausea, vomiting, diarrhea, headaches, lightheadedness, dizziness, diminished appetite, sweating, chills, tremors, paresthesias, fatigue, somnolence, and sleep disturbances (eg, vivid dreams, insomnia). Less common symptoms include electric shock-like sensations, cardiac arrhythmias (more common with tricyclic antidepressants), myalgias, parkinsonism, arthralgias, and balance difficulties. Psychological symptoms may also emerge such as agitation, anxiety, akathisia, panic attacks, irritability, aggressiveness, worsening of mood, dysphoria, mood lability, hyperactivity, mania/hypomania, depersonalization, decreased concentration, slowed thinking, confusion, and memory or concentration difficulties. Greater risks for developing a discontinuation syndrome have been associated with antidepressants with shorter half-lives, longer durations of treatment, and abrupt discontinuation. For antidepressants of short or intermediate half-lives, symptoms may emerge within 2 to 5 days after treatment discontinuation and last 7 to 14 days (APA 2010; Fava 2006; Haddod 2001; Shelton 2001; Warner 2006).
Electroconvulsive therapy
May increase the risks associated with electroconvulsive therapy; consider discontinuing, when possible, prior to ECT treatment.
Pregnancy & Lactation
Pregnancy
Avoid
Only SSRI classified D. Switch to sertraline preconception if possible. If already pregnant and stable, discussion with prescriber is essential — abrupt discontinuation may be more harmful
Lactation
Paroxetine is present in breast milk. The relative infant dose (RID) of paroxetine is 5.6% when calculated using the highest breast milk concentration located and compared to a weight-adjusted maternal dose of 50 mg/day. In general, breastfeeding is considered acceptable when the RID is The RID of paroxetine was calculated using a milk concentration of 255.3 ng/mL, providing an estimated daily infant dose via breast milk of 0.04 mg/kg/day. This milk concentration was obtained following mater
LactMed: monitor the infant.
Monitoring
| Clinical pearl | Serum sodium in at-risk populations (as clinically indicated); mental status for depression, suicide ideation (especially at the beginning of therapy or when doses are increased or decreased), anxiety, social functioning, mania, panic attacks; signs/symptoms of serotonin syndrome; akathisia |
|---|
Chemistry & Properties
| Formula | C19H20FNO3 |
|---|---|
| Molecular weight | 329.37 g/mol |
| IUPAC name | (3S,4R)-3-(1,3-benzodioxol-5-yloxymethyl)-4-(4-fluorophenyl)piperidine |
| CAS | 61869-08-7 |
| PubChem CID | 43815 |
| InChIKey | AHOUBRCZNHFOSL-YOEHRIQHSA-N |
| logP | 3.33 (XLogP 3.5) |
| Polar surface area | 39.72 Ų |
| H-bond acceptors / donors | 4 / 1 |
| Drug-likeness (QED) | 0.93 |
| Lipinski violations | 0 |
SMILES
Fc1ccc([C@@H]2CCNC[C@H]2COc2ccc3c(c2)OCO3)cc1Biology & Pharmacokinetics
Pharmacokinetics
| BBB penetrant | Yes |
|---|
Enzyme interactions
| Enzyme | Role | Detail |
|---|---|---|
| CYP1A2 | Inhibitor | — |
| CYP1A2 | Substrate | — |
| CYP2B6 | Inhibitor | — |
| CYP2C19 | Substrate | — |
| CYP2D6 | Inhibitor | Ki 4.849999999999998 µM |
| CYP2D6 | Substrate | — |
| CYP3A4 | Inhibitor | IC₅₀ 20.000000000000004 µM |
| CYP3A4 | Substrate | — |
Receptor binding (top 14)
| Target | Action | Affinity |
|---|---|---|
| SERT (SLC6A4) | Inhibitor | pKd 10.1 |
| 5-HT Transporter (SLC6A4) | Binding | pKi 9.7 |
| SERT (SLC6A4) | Inhibitor | pKi 9.6 |
| Cholinergic, muscarinic M3 (CHRM3) | Binding | pKi 7.1 |
| Norepinephrine transporter | Binding | pKi 7.0 |
| Cholinergic, muscarinic | Binding | pKi 7.0 |
| Cholinergic, muscarinic M1 (CHRM1) | Binding | pKi 6.8 |
| Cholinergic, muscarinic M4 (CHRM4) | Binding | pKi 6.5 |
| Cholinergic, muscarinic M2 (CHRM2) | Binding | pKi 6.5 |
| Dopamine Transporter (SLC6A3) | Binding | pKi 6.3 |
| Cholinergic, muscarinic M5 (CHRM5) | Binding | pKi 6.2 |
| adrenergic Alpha1A (ADRA1A) | Binding | pKi 6.0 |
| adrenergic Alpha1 | Binding | pKi 5.6 |
| adrenergic Alpha2 | Binding | pKi 5.4 |
Transporters
BCRP (Inhibitor)BSEP (Inhibitor)BSEP (Inhibitor)MDR1 (Inhibitor)MRP1 (Inhibitor)MRP2 (Inhibitor)MRP3 (Inhibitor)MRP4 (Inhibitor)OATP1B1 (Inhibitor)OATP1B1 (Inhibitor)OATP1B3 (Inhibitor)OATP1B3 (Inhibitor)OATP2B1 (Inhibitor)OCT1 (Inhibitor)P-gp (Inhibitor)MDR1 (Substrate)P-gp (Substrate)
Drug–drug interactions (100+, DDInter)
| Interacting drug | Severity | Management |
|---|---|---|
| Astemizole | major | |
| Bupropion | major | |
| Dexfenfluramine | major | |
| Dextromethorphan | major | |
| Diethylpropion | major | |
| Dolasetron | major | |
| Doxepin | major | |
| Doxepin (topical) | major | |
| Eliglustat | major | |
| Fenfluramine | major | |
| Granisetron | major | |
| Iohexol | major | |
| Iopamidol | major | |
| Lorcaserin | major | |
| Mazindol | major | |
| Methylene blue | major | |
| Ondansetron | major | |
| Palonosetron | major | |
| Panobinostat | major | |
| Phentermine | major | |
| Phenylpropanolamine | major | |
| Procarbazine | major | |
| Sibutramine | major | |
| Tamoxifen | major | |
| Abciximab | moderate | |
| Abiraterone | moderate | |
| Acalabrutinib | moderate | |
| Acetohexamide | moderate | |
| Acetylsalicylic acid | moderate | |
| Aldesleukin | moderate | |
| Alimemazine | moderate | |
| Alteplase | moderate | |
| Anagrelide | moderate | |
| Anistreplase | moderate | |
| Antithrombin III human | moderate | |
| Apixaban | moderate | |
| Argatroban | moderate | |
| Azatadine | moderate | |
| Betrixaban | moderate | |
| Bivalirudin | moderate |
Showing 40 of 100+.
Registered Products (9)
| Brand | Form / strength | Pack | Agent | Citizen (JOD) |
|---|---|---|---|---|
| Paroxat | Tablet 20 mg | 20 tab | The Jordan Drugstore Co | 3.380 |
| Paxitab | Tablet 20 mg | 30 tab | Sukhtian Group | 5.170 |
| Unirox | Tablet 20 mg | 30 tab | UNITED PHARM.MFG.CO.LTD(UPM)/JORDAN | 6.330 |
| Paroxat | Tablet 40 mg | 20 tab | The Jordan Drugstore Co | 6.360 |
| Seroxat Tab | Tablet 20 mg | 30 tab | Suleiman Tannous & Sons Co. Ltd | 7.060 |
| Xalexa | Tablet 20 mg | 30 tab | AL Rahma Drug Store | 7.370 |
| Paxitab | Tablet 40 mg | 30 tab | Sukhtian Group | 8.480 |
| Seroxat CR | Tablet 12.5 mg | 30 tab | Suleiman Tannous & Sons Co. Ltd | 9.180 |
| Xalexa | Tablet 30 mg | 30 tab | AL Rahma Drug Store | 11.060 |