Paxil (paroxetine), like other SSRIs (selective serotonin reuptake inhibitors), has the potential to influence fetal development in humans. Such influence has resulted in congenital malformations in newborns, persistent withdrawal symptoms lasting for days to weeks after birth, and as research slowly progresses, is indicating long-term motor skill and other developmental problems in affected children. The US FDA and Health Canada, among other governmental organizations worldwide, continue to add more warnings with regard to Paxil, as well as other SSRI class antidepressants.
The latest FDA warning requires GlaxoSmithKline, Paxil’s manufacturer, to relabel it’s product with a new warning reflecting the change in the FDA’s outlook regarding Paxil, which includes a change from a Category C use to Category D use for pregnant women. Specifically, in the release dated Dec. 8, 2005, the FDA says “ Category D means that studies in pregnant women (controlled or observational) have demonstrated a risk to the fetus. ”
Congenital Malformations
All members of the SSRI drug class have been shown to cross the placenta. As shown in Table 1, paroxetine has the greatest outcome of reported malformations in newborn infants when compared to first trimester maternal use of other antidepressants.
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*Categories of specific antidepressants are mutually exclusive. Data were taken from a GlaxoSmithKline report (available at http://ctr.gsk.co.uk/summary/paroxetine/epip083.pdf [accessed 2005 Oct 26]). Because no major congenital malformations were observed among the offspring of participants exposed clomipramine, desipramine, doxepin, fluvoxamine, imipramine, mitrazapine, nortriptyline, data for these antidepressants are not shown. +Adjusted for age and sex of infant, calendar year of delivery and a maternal diagnosis of pre-eclampsia or eclampsia. The comparator group is the rate malformations among infants of users of any other antidepresant in the first trimester. CI = confidence interval |
Long-term motor skill and other developmental problems
Bercovici’s research also reported that a well-controlled study showed a different trend (to those previously reported) after SSRI exposure [Casper et al. (2003)]. The children of depressed mothers exposed to SSRI or unexposed depressed mothers were followed up to age of 40 months. Their findings indicate that children prenatally exposed to SSRIs scored lower on psychomotor (Bayley Scales of Infant Development test) and lower on the motor quality factors (Bayley Behavioral Rating Scale). The authors suggest one of the side effects of prenatal SSRI exposure may be subtle motor developmental delays.
A recent study, by Zeskind and Stephens (2004), using a systematic prospective study to investigate the prenatal effects of SSRIs on neurobehaviour of newborns found that prenatally exposed infants were hyperactive, tremulous and had behavioural state abnormalities.
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References:
“Paroxetine (Paxil) and congenital malformations” CMAJ • November 22, 2005; 173 (11).
First published November 4, 2005; doi:10.1503/cmaj.051421
Megan Williams* and Eric Wooltorton* Resident, Department of Family Medicine, University of Ottawa; CMAJ
http://www.cmaj.ca/cgi/content/full/173/11/1320#T113
Eduard Bercovici, Prenatal and Perinatal Effects of Psychotropic Drugs on Neuro-cognitive Development in the Fetus JOURNAL ON DEVELOPMENTAL DISABILITIES,
VOLUME 11 NUMBER 2 IN PRESS
http://www.oadd.org/publications/journal/issues/vol11no2/download/bercovici.pdf
Casper, R. C., Fleisher, B. E., Lee-Ancalas, J. C., Gilles, A., Gaylor, E., DeBattista, A., & Hoyme, H. E. (2003). Follow-up of children of depressed mothers exposed or not exposed to antidepressant drugs during pregnancy.
Journal of Pediatrics, 142, 402-408.
Costei, A. M., Kozer, E., Ho T, Ito S., & Koren, G. (2002). Perinatal outcome following third trimester exposure to paroxetine.
Archives of Pediatrics & Adolescent Medicine, 156,
1129-1132.
Ward, R. K., & Zamorski, M. A. (2002). Benefits and risks of psychiatric medications during pregnancy.
American Family Physician, 66, 629-636.
Zeskind, P. S., & Stephens, L. E. (2004). Maternal selective serotonin reuptake inhibitor use
during pregnancy and newborn neurobehavior.
Pediatrics, Feb 2004 113, 368-375.
http://www.pediatrics.org/cgi/content/full/113/2/368