Comparative Pharmacology
Head-to-head clinical analysis: PAXIL versus PROZAC WEEKLY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PAXIL versus PROZAC WEEKLY.
PAXIL vs PROZAC WEEKLY
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Paroxetine is a selective serotonin reuptake inhibitor (SSRI) that potentiates serotonergic activity in the central nervous system by inhibiting the reuptake of serotonin (5-HT) from the synaptic cleft, leading to increased serotonin levels.
Selective serotonin reuptake inhibitor (SSRI); potentiates serotonergic activity by blocking reuptake of serotonin at the presynaptic neuronal membrane.
20 mg orally once daily, typically in the morning; may be increased in 10 mg/day increments at intervals of at least 1 week to a maximum of 50 mg/day.
90 mg orally once weekly
None Documented
None Documented
Mean terminal half-life 21 hours (range 3–65 hours); steady-state achieved within 7–14 days; nonlinear kinetics with dose increase leading to disproportionate increases in half-life due to saturable hepatic metabolism (CYP2D6).
Fluoxetine: 4-6 days after single dose, 4-6 days (extended to 7-9 days with chronic dosing due to autoinhibition of CYP2D6); norfluoxetine: 9-31 days. Steady state achieved after 2-4 weeks.
Renal: 64% (2% unchanged, 62% as metabolites); Fecal: 36% via bile; urinary excretion of unchanged paroxetine <2%.
Renal excretion of metabolites (primarily fluoxetine glucuronide and norfluoxetine glucuronide) accounts for approximately 80% of elimination; fecal excretion accounts for approximately 15%.
Category C
Category C
SSRI Antidepressant
SSRI Antidepressant