Comparative Pharmacology
Head-to-head clinical analysis: CELEXA versus PAXIL CR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CELEXA versus PAXIL CR.
CELEXA vs PAXIL CR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Selective serotonin reuptake inhibitor (SSRI); potentiates serotonergic activity in the CNS by blocking reuptake of serotonin into presynaptic neurons.
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.
20 mg orally once daily initially, may increase to 40 mg once daily after at least 1 week; maximum 40 mg/day.
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.
None Documented
None Documented
Terminal elimination half-life is approximately 35 hours (range 23–45 h) in healthy adults. This long half-life allows once-daily dosing; steady state is reached in about 1 week. In elderly patients, half-life may extend to 45–90 hours.
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.
Primarily renal: 75% as metabolites (10% as parent citalopram, 65% as desmethylcitalopram, didesmethylcitalopram, and citalopram-N-oxide). Fecal excretion accounts for approximately 20% of the dose. Biliary excretion minimal.
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.
Category C
Category C
SSRI Antidepressant
SSRI Antidepressant