Excretion of paroxetine into breast milk.
BACKGROUND
The study was carried out to quantify the excretion of the selective serotonin reuptake inhibitor paroxetine in breast milk.


METHODS
In 6 lactating women, the concentrations of paroxetine in breast milk and serum were studied at the times for assumed minimum (24 hours after dose intake) and maximum (4-7 hours after dose intake) drug levels in milk. Moreover, a seventh subject was studied with frequent and regular sampling throughout a dose interval of 24 hours at 2 different dose levels.


RESULTS
The mean milk/serum concentration ratios in the first 6 subjects ranged from 0.39 to 1.11 (overall mean +/- SD = 0.69 +/- 0.29), and the mean estimated dose to the infants ranged from 0.7% to 2.9% (overall mean +/- SD = 1.4% +/- 0.79%) of the weight-adjusted maternal dose. Based on area-under-the-curve data from the seventh subject, the milk/serum concentration ratio was 0.69 at a dose of 20 mg/day and 0.72 at a dose of 40 mg/day; the estimated relative doses to the infant were 1.0% and 2.0%, respectively. The mean increase in milk paroxetine concentrations from assumed minimum to assumed maximum was 61% (range, 4%-172%; p < .01). The mean paroxetine concentration in hindmilk was 78% higher than in foremilk (range, 16%-169%; p < .01), an increase that was parallel to the increase in milk triglyceride levels (r = 0.83, p = .005). No adverse drug reactions or unusual behaviors were reported in the infants.


CONCLUSIONS
The study indicates that the relative dose to a suckling infant for paroxetine is lower than that reported for fluoxetine and citalopram and higher than that reported for sertraline and fluvoxamine.
Ohman
R
R
Department of Psychiatry, Ostersund Hospital, Sweden.
Hägg
S
S
Carleborg
L
L
Spigset
O
O
D000328:Adult; D001942:Breast Feeding / Q000009:adverse effects*; D015283:Citalopram / Q000493:pharmacokinetics; D003866:Depressive Disorder / Q000188:drug therapy* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005473:Fluoxetine / Q000493:pharmacokinetics; D016666:Fluvoxamine / Q000493:pharmacokinetics; D006801:Humans; D007774:Lactation / Q000097:blood / Q000187:drug effects / Q000378:metabolism; D008895:Milk, Human / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D016584:Panic Disorder / Q000188:drug therapy / Q000378:metabolism; D017374:Paroxetine / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D017367:Selective Serotonin Reuptake Inhibitors / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D020280:Sertraline / Q000493:pharmacokinetics; D014280:Triglycerides / Q000032:analysis / Q000097:blood
D015283:Citalopram; D005473:Fluoxetine; D016666:Fluvoxamine; D017374:Paroxetine; D017367:Selective Serotonin Reuptake Inhibitors; D020280:Sertraline; D014280:Triglycerides