Comparative Pharmacology
Head-to-head clinical analysis: PAXIL versus SARAFEM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PAXIL versus SARAFEM.
PAXIL vs SARAFEM
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.
SARAFEM (fluoxetine) 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, enhancing serotonin effects in the synaptic cleft.
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.
10-20 mg orally once daily initially, may increase to 40 mg/day after 3 weeks if needed; maximum 80 mg/day
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, 4-16 days after chronic dosing; norfluoxetine: 4-16 days after single dose, up to 16-20 days after chronic dosing. The long half-life minimizes withdrawal symptoms and allows for once-weekly dosing.
Renal: 64% (2% unchanged, 62% as metabolites); Fecal: 36% via bile; urinary excretion of unchanged paroxetine <2%.
Primarily renal excretion of fluoxetine (10%) and its active metabolite norfluoxetine (7.5%) as unchanged drug; the remainder is excreted as conjugates and other metabolites. Approximately 2.5% is excreted in feces.
Category C
Category C
SSRI Antidepressant
SSRI Antidepressant