It is important to complete an individual risk assessment for your patient and to apply the principles of prescribing in breastfeeding when looking at the available information and making treatment decisions.
This article includes some commonly prescribed antidepressants which are not classed as selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs). Many other antidepressant medicines are also available, and may need to be added in various combinations for more specialist situations. Contact our specialist service for further advice.
Published evidence shows that milk levels with duloxetine, mirtazapine, trazodone, and venlafaxine are generally very small to negligible. However, there have been a few case reports of higher milk levels with venlafaxine.
These antidepressants, or their active metabolites, have relatively long half-lives, which could result in accumulation and increased risk of side effects in the infant due to their underdeveloped clearance capacity, particularly in the neonatal period. However, in the majority of cases, no infant side effects were reported.
The National Institute for Healthcare Excellence (NICE) advises avoiding sharing a bed with the infant when sedating medication has been used, due to the increased risk of sudden unexpected death in infancy.
Some of these medicines are used for other therapeutic indications. Recommendations apply to any indication the medicine is being used for.
Untreated or inadequately treated depression can have adverse effects on the mother and infant and it is important that the mother receives effective treatment and does not stop taking the antidepressant suddenly.
Treatment choice should primarily focus on controlling symptoms with suitability in breastfeeding a secondary consideration.
If duloxetine, mirtazapine, trazodone or venlafaxine have been used successfully during pregnancy, there is no need to switch to a preferred choice in breastfeeding, as long as the infant has been born full term and healthy.
These antidepressants can cause discontinuation symptoms if stopped abruptly, particularly venlafaxine and duloxetine. This may make it more difficult to stop treatment, and should be considered when making medicine choices.
Neonatal withdrawal syndrome
Infants exposed to duloxetine, mirtazapine, trazodone or venlafaxine during pregnancy should be monitored for withdrawal symptoms. Symptoms may be more severe when exposed to more than one centrally acting medicine.
Symptoms may vary but could include poor adaptation, jitteriness, irritability, poor gaze, agitation, hypotonia, hypoglycaemia, gastro-intestinal disturbances, respiratory problems and convulsions. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry. Symptoms typically last for a few days (although symptoms could be delayed or prolonged with mirtazapine due to its extended half-life), but usually resolve without intervention. Continuing breastfeeding may help relieve withdrawal effects.
It may be difficult to distinguish between neonatal withdrawal symptoms and potential side effects from antidepressant exposure through breast milk. If symptoms do not resolve a few days after birth (or longer for mirtazapine), consider that side effects from exposure through breast milk may be a potential cause.
Effect on breastfeeding
Those taking an antidepressant may have more difficulty breastfeeding, particularly with establishing breastfeeding. The underlying condition may contribute to this and additional breastfeeding support may be required.
Use with caution
Monitor infants for irritability, restlessness, drowsiness, gastrointestinal symptoms, poor feeding or not waking to feed and appropriate weight gain.
Published evidence with doses of up to 90mg daily, shows that duloxetine passes into breast milk in negligible amounts (0.1% to 0.8% of the weight adjusted maternal dose). Infant exposure is likely to be reduced as duloxetine is unstable in acid conditions, and is likely to be degraded in the infant’s gastro-intestinal tract.
Infant serum levels, when measured, were low or undetectable.
No side effects have been reported in breastfed infants.
Use with caution
Monitor infants for irritability, drowsiness, gastrointestinal symptoms, changes in feeding or not waking to feed, and appropriate weight gain.
Limited published evidence with doses up to 120mg daily, shows that mirtazapine passes into breast milk in very small amounts (in most cases less than 5% of the weight adjusted maternal dose).
Infant serum levels, when measured, were mainly low or undetectable, although higher levels were found in one case report.
Although mirtazapine has a long half-life, which theoretically could result in accumulation and an increased risk of infant side effects, no problems have been reported in breastfed infants. Short-term follow-up showed that infants had normal development for their age.
Use with caution
Monitor infants for irritability, drowsiness, gastrointestinal symptoms, poor feeding or not waking to feed and adequate weight gain.
Limited published evidence with doses up to 200mg daily, shows that trazodone passes into breast milk in negligible amounts (approximately 0.6% of the weight adjusted maternal dose).
There are no data looking at infant serum levels.
No side effects have been reported in breastfed infants. Normal growth, development and behaviour was observed in a few infants followed for up to 12 months, whose mothers were taking 50mg to 200mg daily.
Use with caution
Monitor infants for irritability, agitation, colic, drowsiness, gastrointestinal symptoms, poor feeding or not waking to feed and appropriate weight gain.
A moderate amount of published evidence of use during breastfeeding indicates that venlafaxine and its active metabolite desvenlafaxine, pass into breast milk in variable quantities, ranging from very small to moderate amounts (2.7% to 13.3% of the weight adjusted maternal dose). One single-case report found some higher milk levels (9 to 23% of the weight adjusted maternal dose), however infant serum levels were low and no side effects were reported.
Infant serum levels of venlafaxine and desmethylvenlafaxine have been detectable in variable amounts in most infants studied. In the majority of infants, serum levels were low. However, a few had serum levels of 10% or 37% of the maternal serum level. No side effects were observed in these infants.
No side effects were noted in the majority of infants exposed to venlafaxine in breast milk, and normal development was seen in infants followed for up to 18 months. Minor side effects reported in a small number of breastfed infants, include drowsiness, fatigue, poor feeding, colic, an increased startle response, jitteriness and sleeplessness. Two infants had decreased weight gain at 6 months of age.
The NHS website provides advice for patients on the use of specific medicines in breastfeeding.
Get in touch with the UK Drugs In Lactation Advisory Service (UKDILAS), our specialist breastfeeding medicines advice service if you need support in the following situations:
- you need further advice
- the medicine in question is not included in our advice
- the infant is unwell or premature
- multiple medicines are being taken
About our recommendations
Recommendations are based on published evidence where available. However, evidence is generally very poor and limited, and can require professional interpretation. Assessments are often based on reviewing case reports which can be conflicting and lack detail.
If there is no published clinical evidence, assessments are based on: pharmacodynamic and pharmacokinetic principles, extrapolation from similar drugs, risk assessment of normal clinical use, expert advice, and unpublished data. Simulated data are now increasingly being used due to the ethical difficulties around gathering good quality evidence in this area.
Full referencing is available on request.
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