PFPC Daily - December 8, 2004

Laine K, Kytola J, Bertilsson L - "Severe Adverse Effects in a
Newborn with Two Defective CYP2D6 Alleles After Exposure to
Paroxetine During Late Pregnancy" Ther Drug Monit 26(6):685-687 (2004)

ABSTRACT:

Paroxetine, like other SSRIs, is reported not to increase the
number of malformations in infants exposed to these drugs in utero.
However, late pregnancy exposure to SSRIs sometimes leads to
perinatal complications resembling the symptoms seen in serotonergic
overstimulation. We report here a case of third trimester paroxetine
exposure with adverse birth outcome in a newborn. The clinical
symptoms in the infant included severe tremor and rigidity
as well as loose stools during the first 4 days of life. Plasma
paroxetine concentrations in infant plasma were quite low after
birth, but she was genotyped to be a poor metabolizer of CYP2D6, the
enzyme catalyzing the metabolism of paroxetine. In accordance with an
earlier report, we suggest that even low plasma concentrations of
paroxetine may be related to perinatal complications in infants
exposed to paroxetine during late pregnancy and that the poor
metabolizer genotype of CYP2D6 may be a risk factor for these
complications.