Comparative Pharmacology
Head-to-head clinical analysis: PAXIL CR versus PROZAC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PAXIL CR versus PROZAC.
PAXIL CR vs PROZAC
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 in the CNS by blocking the reuptake of serotonin into presynaptic neurons.
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.
20 mg orally once daily, initially; may increase to 40 mg once daily after several weeks; maximum 80 mg once daily.
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; norfluoxetine: 4-16 days; extensive accumulation with chronic dosing, steady-state in 4-5 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: ~80% (primarily as metabolites, <10% unchanged); fecal: ~15%
Category C
Category C
SSRI Antidepressant
SSRI Antidepressant