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Counseling pregnant women who are treated with paroxetine

Adrienne Einarson RN and Gideon Koren MD

November 2005 - Special Supplement

ABSTRACT

QUESTION

I have always reassured my patients that taking an SSRI in pregnancy would not increase their risk for having a child with a major malformation. However, I recently read the warning from Health Canada regarding the release of a study from GSK, stating that infants exposed to paroxetine may be at a higher risk of congenital malformations, specifically cardiovascular defects. Some of my pregnant patients who are taking paroxetine (Paxil) heard about this information in the media and called me to ask if they should stop taking it. What should I tell them?

ANSWER

The new warning is based on small non peer review, unpublished studies. It ignored 2 published studies that failed to show such association, and no such association has been shown for SSRI?s as a class. The data suggested that even if there is a risk, it is small. The warning does not disclose the details of the cardiovascular malformations in these studies. Many cases of ventricular septal defect, the most common cardiac malformation, resolve spontaneously. Concerned mothers to be should know that beyond the first trimester a drug cannot cause cardiac malformation. Failure to treat depression during pregnancy can have significant negative ramifications for both mother and child, and it is the strongest predictor of postpartum depression.


To date, none of the SSRI's have been associated with an increased risk for major malformations, including cardiovascular anomalies.1 Recently, GlaxoSmithKline (GSK) released an advisory2 which subsequently was incorporated in a Health Canada Advisory,3 indicating that infants exposed to paroxetine at the time of organogenesis were at a higher risk of congenital malformations, particularly cardiovascular (ventricular septal) defects. This information was based on an unpublished, retrospective, epidemiologic study, conducted by GSK, as well as 3 abstracts presented at scientific conferences.

The GSK study claimed a prevalence of major malformations as a whole was 4% and for cardiovascular malformations it was 2%.2 Alwan et al, presented a case control study that showed an increased risk of major malformations in general, but no association with cardiovascular defects.4 Wogleus et al, claimed a small increase in cardiovascular malformations based on a prescription database study where it was not known whether pregnant women actually took the medication.5 Finally, Diav-Citrin et al, presented a prospective comparative study, that also showed a small increase in the rates of cardiovascular defects (1.9%).6 At the present time, these data are based on unpublished, non peer-reviewed studies. Therefore, one needs to be extremely careful in accepting them as scientific facts. It should be noted that cardiovascular malformations are common in the general population, occurring in approximately 1% of all births. In addition, we do not know the details of the cardiovascular malformations and some could be, in any of these preliminary reports, minor. For example, a large proportion of ventricular septal defects (of the muscular type) resolve spontaneously. The data suggest that even if there is a malformation risk it is of marginal magnitude. Of importance, this association has not been found with other SSRI drugs. To date there has been no evidence that in a class of drugs, only one agent is associated with an increased risk for birth defects while the others are not.

This suggested association has not been found in previous published studies on paroxetine. Ericson et al published a study which included 122 cases of embryonal exposure to paroxetine and there was no difference in the rates of cardiovascular defects between paroxetine and controls.7 Similarly, Motherisk published a study of 267 women exposed to SSRIs where 2 cardiovascular defects were described. One of these occurred among 97 fetuses exposed to paroxetine, a similar rate to the other SSRIs (1/169).8 Further, we have re-analyzed our recent meta-analysis of congenital anomalies with SSRIs as compared to controls1 and could not detect an increased risk of cardiac malformation for SSRIs as a class. Last, a large case control study from Sweden has failed to show an association between cardiac malformations and SSRI (OR 0.95, 95% CI 0.62-1.44).9 Taken together, there are 3 peer reviewed published studies showing no increased rates of cardiovascular malformations with paroxetine. One of the 4 recent unpublished reports also could not find increased risk of cardiovascular malformations whereas 3 had an apparent small risk.

Failure to treat depression during pregnancy can have significant negative ramifications for both mother and child, most notably, it is the strongest predictor of postpartum depression, which can sometimes have tragic consequences.10

As expected from such unbalanced reports, many women regrettably discontinued their Paxil even after the first trimester, when cardiac malformation cannot be produced.

Women and their physicians should discuss this information and make an informed decision, whether or not to continue on this medication during pregnancy. As shown in the Table, concerned patients can be offered ultrasound and echocardiogram which can rule out fetal cardiac problems in early pregnancy. Antidepressants should never be stopped abruptly as this can have serious ramifications for the mother.11 If a woman does decide following a discussion with her physician, that she wants to discontinue paroxetine, the drug should be slowly tapered off over a number of weeks.

Motherisk Guidelines for Managing Pregnant Women on Paroxetine and other SSRIs

  • Ensure that diagnosis and symptoms warrant an antidepressant.
  • Ensure that the woman is on an appropriate dose that controls her symptom. In late pregnancy many women need more of the medication.
  • An ultrasound or fetal echocardiogram may detect cardiovascular malformations.
  • Never discontinue the drug 'cold turkey' rather, taper it off.

References

  1. Einarson TR, Einarson A. Newer antidepressants in pregnancy and rates of major malformations: a meta-analysis of prospective comparative studies. Pharmacoepidemiol Drug Saf. 2005 Mar 1; [Epub ahead of print]
  2. GSK Advisory October 2005. http://ctr.gsk.co.uk/welcome.asp
  3. Health Canada Advisory October 2005. http://hc-sc.gc.ca/dhp-mps/medeff/advisories-avis/prof/index e.html
  4. Alwan S, Reefhuis J, Rasmussen S, et al. (Abstract) Maternal use of selective serotonin re-uptake inhibitors and risk for birth defects. Birth Defects Research (Part A): Clinical and Molecular Teratology 731: 291, 2005
  5. Wogleus P, Norgaard M, Muff Munk E, et al. (Abstract) Maternal use of selective serotonin reuptake inhibitors and risk of adverse pregnancy outcomes. Pharmacoepidemiology and Drug Safety 14: 143S, 2005
  6. Diav-Citrin et al, Pregnancy outcome after gestation exposure to paroxetine: (Abstract) A prospective controlled cohort study. Teratology meeting St. Petersburg, Florida, USA. June 2005
  7. Ericson A, Kallen B, Wilholm BE. Delivery outcome after the use of antidepressants in early pregnancy. European Journal of Clinical Pharmacology 55: 503-508, 1999
  8. Kulin NA, Pastuszak A, Sage S, et al. Pregnancy outcome following maternal use of the new selective serotonin reuptake inhibitors- A prospective controlled multicenter study. JAMA 279: 609-610, 1998
  9. Kallen BA, Otterblad Olausson P. Maternal drug use in early pregnancy and infant cardiovascular defect. Reprod Toxicol 2003; 17: 255-61
  10. Beck CT. Postpartum depression predictors inventory ? revised. Adv Neonatal care. 2003 Feb;3(1):47-8
  11. Einarson A, Selby P, Koren G. Abrupt discontinuation of psychotropic drugs during pregnancy: fear of teratogenic risk and impact of counseling. J Psychiatry Neurosci 2001; (1): 44-8

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