Comparative Pharmacology
Head-to-head clinical analysis: CELEXA versus PAXIL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CELEXA versus PAXIL.
CELEXA vs PAXIL
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) 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.
20 mg orally once daily initially, may increase to 40 mg once daily after at least 1 week; maximum 40 mg/day.
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.
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.
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).
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: 64% (2% unchanged, 62% as metabolites); Fecal: 36% via bile; urinary excretion of unchanged paroxetine <2%.
Category C
Category C
SSRI Antidepressant
SSRI Antidepressant