Comparative Pharmacology
Head-to-head clinical analysis: PAXIL CR versus PROZAC WEEKLY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PAXIL CR versus PROZAC WEEKLY.
PAXIL CR 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). It potentiates serotonergic activity in the CNS by inhibiting the reuptake of serotonin at the presynaptic neuronal membrane, resulting in increased serotonin concentrations in the synaptic cleft.
Selective serotonin reuptake inhibitor (SSRI); potentiates serotonergic activity by blocking reuptake of serotonin at the presynaptic neuronal membrane.
12.5-37.5 mg orally once daily in the morning; initial dose 12.5 mg/day, titrate by 12.5 mg/day at intervals of at least 1 week to maximum 50 mg/day.
90 mg orally once weekly
None Documented
None Documented
The terminal elimination half-life of paroxetine (PAXIL CR) is approximately 15-20 hours. This supports once-daily dosing and requires about 5-7 days to reach steady-state concentration.
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 excretion accounts for approximately 64% of the administered dose, with 2% as unchanged parent drug and the remainder as metabolites. Fecal excretion accounts for about 36%, mostly as metabolites. Less than 1% is excreted in bile.
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