Intro
Brand name: Paxil, Paxil CR, Brisdelle
Class: SSRI
MOA: Selective Serotonin Receptor Inhibitor
Indications
FDA Indications: MDD, OCD, Panic Disorder, Social Anxiety Disorder, GAD, PTSD
Off-label uses: Vasomotor symptoms of menopause, PMDD, Premature ejaculation (SSRI of choice for this)
Dosing
Forms:
->Instant Release: Tablet: 10 (scored), 20 (scored), 30, 40
->Extended/Controlled Release: Tablet: 12.5, 25, 37.5
->Liquid 10mg/5mL
Starting: 20mg qAM
Maintenance: 20-60 depending on use
Max: 50mg (MDD, PTSD, SAD, GAD), 60mg (OCD, Panic Disorder). Can go higher for OCD if needed.
Pharmacokinetics
Half-life: 21 hr
Inhibits: CYP2D6
Side Effects
Serious: Serotonin Syndrome, SIADH, increased risk of SI in children, Risk of birth defects
Notable: More likely to cause withdrawal relative to other SSRIs (short half life), Many CYP interactions, Sexual dysfunction (delayed ejaculation, ED, anorgasmia), GI (n/v dec appetite), Sedation, Bruising, anticholinergic effects (constipation)
Gems
-Strong CYP2D6 Inhibitor
-Risk of birth defects. Paroxetine is “Category D” antidepressant
-While paroxetine does have indications for anxiety conditions, there is not much evidence pointing to its superiority over other SSRIs
-Given side effects and drug-drug interactions, it is reasonable to consider other SSRI options before paroxetine
-Anticholinergic effects, watch for constipation
-SSRI of choice for premature ejaculation
-Given short half life, missed doses can precipitate withdrawal
-Paxil CR (extended release form) is less likely to cause nausea, however even with IR form nausea will likely dissipate after 1-2 weeks
-Brisdelle is 7.5mg paroxetine capsule FDA indicated for tx of moderate to severe vasomotor symptoms associated with menopause. However not really a first line choice.
Special populations
Renal Impairment: Initial 10mg qDay (for IR), max 40mg qDay
Hepatic Impairment: Initial 10mg qDay (for IR), max 40mg qDay
Elderly (60y/o+): Initial 10mg qDay (for IR), max 40mg qDay
Pregnancy: Not generally recommended in pregnant women. Use in late pregnancy associated w/ higher risk of neonatal complications
References
Prescriber’s Guide: Stahl’s Essential Psychopharmacology