Medication Safety Review Series: Wellbutrin (Bupropion)
This series will review a medication (commonly used in mental health treatment) weekly to describe its safety profile and answer five important questions. Today we focus on bupropion (brand name: wellbutrin)
What is wellbutrin and what is it used for?
This medication is a commonly prescribed antidepressant. It is often used as a first-line treatment option because it is well tolerated and avoids some of the side effects of other medications (for example, no sexual side effects and no weight gain). It has also been prescribed to help with smoking cessation. I have had many women who continue to take this medication during pregnancy and postpartum.
How safe is wellbutrin in early pregnancy?
In early pregnancy, we are most concerned with organ formation, which happens during the first trimester. Interestingly, one study found no significant increased risk of any cardiac defects in the first trimester, but when another research group re-analyzed the data and used different definitions, they did find a slight difference.
The second study suggested that using this medication in the first trimester increases the risk of a particular type of heart defect (related to the flow of blood from the left ventricle) compared to other antidepressants and compared to using this medication outside the first trimester. This is a testament to the fact that research and statistics are imperfect.
Another study also found a slight increase (from 0.82/1000 to 2.1/1000) in a particular type of cardiac defect, but did not factor in several issues that could be alternative explanations for this difference. For example, in this study the investigators did not factor in the illness of depression and did not distinguish between women taking the medication for depression compared to smoking cessation. We do know that depression and certainly smoking come with their own risks during pregnancy.
However, overall the research suggests that the rate of general malformations in infants exposed to bupropion is about 2-3%, which is in the range of the general population (2-4%) for birth defects. A large study from 2007 noted that the specific rate of cardiac defects was about 10.7/1000 (a number that did not differ from comparison groups and which is in line with national averages).
How safe is wellbutrin in later pregnancy and delivery? Are there any long-term consequences to this medication?
Unfortunately, there is no research currently available that answers these two important questions clearly. It is often much easier to answer the first safety question (about birth defects) than to answer questions about more long-term outcomes – it takes much less time and the answers are more clear cut.
Another difficulty is that much of the research on bupropion relates to its function as a medication to help with smoking cessation, rather than as an antidepressant. Smoking and depression have very different risks during pregnancy and postpartum. Similarly, bupropion has been prescribed to help with concentration and attention problems. Some preliminary studies have found an association with exposure to bupropion during pregnancy and the development of ADHD in children later on. However, there could be confounding factors – for example, women who choose to take bupropion may themselves have attention problems. We also know that children are more vulnerable to ADHD if a parent has a history of depression or ADHD.
Is it safe in breastfeeding?
The data to answer this question is limited, relying only on a few case reports. However, it is believed that bupropion crosses into breast milk at a low rate. In most cases levels of the medication were undetectable in the infants or up to about 2% of the maternal levels. There has been a report of an infant who had a seizure, though levels were never measured and causation could not be established.
References:
Cole, J.A. et. al. Bupropion during pregnancy and the prevalence of congenital malformations. 2007. Pharmacoepidemiology and Drug Safety, 16: 474-484.
Alwan, S. et. al. Maternal use of bupropion and risk for congenital heart defects. 2010 American Journal of Obstetrics & Gynecology, 203(52).
Figueroa R. et. al. Use of antidepressants during pregnancy and risk of attention-deficit/hyperactivity disorder in the offspring. 2010. J Dev Behav Pediatr. 31(8):641-648.
Freeman, M.P. ADHD and pregnancy. 2014. Am J Psychiatry 171(7):723-8