Medication Safety Review: Zolpidem (Ambien)

Learn about the safety of using zolpidem during pregnancy & delivery, its long-term consequences, & breast-feeding considerations

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 zolpidem (brand name: Ambien)

What is it and what is it used for?

Zolpidem is a medication used to help with sleep, a sedative that comes both in immediate and extended release forms. Sleep is essential, particularly during pregnancy, as poor sleep can lead to worse obstetrical outcomes. Poor sleep may also be a marker of depression or anxiety in pregnancy (see my articles on Sleep Disturbance in Pregnancy, Depression During Pregnancy, & Anxiety Disorder During Pregnancy). Therefore, in this article we will look at the safety of one of the most commonly used for insomnia.

How safe is it in early pregnancy?

As with many other medications in pregnancy, there are few studies looking at safety because there is a dearth of research of pregnant women. It is known, however, that zolpidem crosses the placenta.

One study published in 2009 found no increased risk of birth defects in babies whose mothers took zolpidem during pregnancy compared with those who did not. This was similar to a smaller, earlier study that took place in England and a much larger study that took place in Taiwan from 2010.

How safe is it in later pregnancy and delivery?

The study I noted above, from 2009, found a trend towards higher rates of preterm delivery and lower birth weight infants in those exposed to zolpidem, but the trends were not statistically significant. This may be because it was a relatively small investigation. The strength of this study is that both groups of women (those taking and those not taking zolpidem) were also diagnosed with depression and taking medication for depression. This is important because the illness of depression itself and the medication used to treat it can affect obstetrical outcomes. The study also notes that women who reported longer use of zolpidem (more than 10 weeks) did not have any higher rates of complications.

In contrast, the Taiwan study did find an increase in those two complications – preterm birth and low birth weight – as well as an increase in small for gestational age infants and in the rates of c-sections. Notable, however, is that while this study did make sure to control for complications of pregnancy like hypertension and diabetes, it did not take into account mothers’ depression or emotional health during pregnancy. It did exclude women who had a history of mental disorders. Because this study was also based on a large registry, there were limitation to the information accessible to the researchers. For example, they were unable to confirm whether the woman were actually taking the medication (just that it was prescribed to them).

The take-home point is that the decision to take zolpidem is not an easy one and involves carefully weighing risks and benefits of the medication as well as the risks of untreated insomnia (discussed elsewhere). Perhaps that means taking a lower effective dose or taking the medication less frequently. At the same time, the consequences of prolonged sleep deprivation can be significant and are important to factor into this decision.

Are there long-term consequences of using this medication?

There are, unfortunately, no available studies that have compared the long-term cognitive and developmental functioning of infants who were exposed to zolpidem in utero.

Is it safe in breastfeeding?

Zolpidem is metabolized by the body very quickly. It passes into the breastmilk in very low amounts, less than 0.02%. The drug is undetectable in milk more than 13 hours after it is ingested. Based on these two factors, it is relatively safe to take during breastfeeding.

However, it is important to also consider the impact on your ability as a mom to wake up for the baby’s needs. Zolpidem is a sedating medication, and women can respond in different ways, so I often recommend that the first night a woman is trying this medication to ensure there is another responsible adult available to care for the infant.

It is also essential that if taking this medication, to ensure that your infant is in a safe place – a crib, bassinet or co-sleeper – rather than in bed with parents.

Want to learn more about zolpidem and related topics?
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Selected References:
Juric, S. et. al. Zolpidem (Ambien) in pregnancy: Placental passage and outcome. Arch Womens Ment Health (2009) 12: 441-446.

Wang, L.H. et. al. Increased risk of adverse pregnancy outcomes in women receiving zolpidem during pregnancy. Clinical Pharmacology & Therapeutics (2010) 88(3): 369.