paroxetine PAXIL

Class: SSRI
FDA Indications: MDD, Panic Disorder, OCD, GAD, PTSD
Off-Label Use: Vasomotor Symptoms Of Menopause, Diabetic Neuropathy, Neurocardiogenic Syncope, IBS
Prescribing
Forms: 10, 20, 30, 40mg tablet
Dose Range: 10-60 mg/day
Starting: start at 10-20 mg qd, wait and reassess in a few weeks, then ↑ by 10mg increments weekly, max 50 mg qd
Stopping: ↓ 10 mg per day Q5-7 days with a final dose of 5-10 mg per day before discontinuation

NAMI drug fact sheet

Precautions
Contraindications: Concomitant use of MAOIs
Serious Side Effects: Serotonin syndrome; ↑ risk of SI in children and young adults; may impair platelet aggregation; SIADH
Side Effects: headache, sedation/somnolence, dizziness, weakness, decreased libido, constipation, weight gain, anorgasmia, xerostomia, increased sweating, diarrhea, nausea, insomnia, akathisia
Pharmacodynamics
1° MOA: Selective serotonin reuptake inhibitor
2° MOA: Weak NET inhibition
Target: SERT, NET
Pharmacokinetics
t½: 21 (3-65)° TMAX: 5-6°
Substrate of: 2D6
Inhibits: 2D6 (strong, dose-dependent); Induces:
Active Metabolites:
DDIs
  • - DO NOT CO-PRESCRIBE WITH MAOIs (need a 5 t½ washout perioid)
  • - 2D6 inhibitors (in addition to itself) can ↑ serum levels; as a 2D6 inhibitor itself it can increase levels of co-prescribed 2D6 substrates
Misc
  • - most serotonergic SSRI → most weight gain among SSRIs
  • - most anticholinergic SSRI → most sedation among SSRIs
  • - NOS inhibition → most sexual dysfunction among SSRIs
  • - NRI activity may confer more anxiolysis compared to other SSRIs
  • - significant withdrawal if not gradually tapered
  • - nonlinear pharmacokinetics; inhibits its own metabolism i.e. t½ ↑s with dose ↑s, so a 50% dose ↑ can ↑ serum levels by 100%
  • - has not been implicated in QTc prolongation
Special Populations

Category C—May be less safe than than other SSRIs. Associated with cardiac malformations with high-dose, first-trimester use (other studies failed to replicate)

RID 0.5-2.8%; ∅AE's have been reported for majority of paroxetine-exposed infants

↓ clearance in the elderly; lower starting dose is recommended

Significantly affected by severe renal disease (CrCl?< 30 ml/min), 4-fold ↑'s in plasma concentrations have been reported

Initial dosage should be reduced in patients with severe hepatic impairment

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Last updated January 20 2018 15:32:06. Disclaimer: This website does not provide medical advice, nor is it a substitute for clinical judgment.