Case-based learning: sedating medicines, breastfeeding and safe sleeping advice

Pharmacists across sectors are ideally placed to give informed advice about taking medicines while breastfeeding. Medicines may be taken during pregnancy or newly started by someone who is already breastfeeding, and sometimes there is a need to restart a medicine post-partum that was stopped during pregnancy. The aim should be to ensure adequate treatment, while reducing risks to the infant and protecting the breastfeeding relationship^​1​.

It is important to consider the benefits of breastfeeding to make a balanced risk assessment when making decisions about medicines use in breastfeeding. Breastfeeding provides nutrition tailored to the infant’s needs, and there is also evidence that it has both short-and long-term health benefits for both infants and mothers^​2,3​. Breastfed infants have a reduced risk of acute and chronic illnesses compared to formula-fed infants, including: infection, diabetes, asthma, heart disease, certain allergic conditions and inflammatory bowel disease.

Evidence also suggests that breastfeeding confers benefits to the mother, including lowering their risk of breast and ovarian cancer, type 2 diabetes mellitus and cardiovascular disease^​3​. Breastfeeding also has a reduced environmental impact compared with infant formula feeding^​4​. As a result, breastfeeding should be viewed as a public health priority. 

The World Health Organization and NHS recommend exclusive breastfeeding for the first six months of life, followed by continued breastfeeding alongside complementary foods for up to two years or beyond^​5,6​. Advising to stop breastfeeding is therefore not a “no-risk” option for either the mother or the infant as they would lose the benefits of breastfeeding. However, results of a 2025 systematic review revealed that up to 58% of women with chronic or severe acute conditions stopped breastfeeding earlier than intended owing to medication related issues. In the majority of cases, this could have been avoidable^​7​. The UK Drugs in Lactation Advisory Service, which the authors are affiliated with, can provide advice on complex cases involving medicines in breastfeeding.

Sudden infant death syndrome (SIDS) is a rare condition where a baby dies suddenly and no causal explanation is found^​8​. Bedsharing or co-sleeping with an infant following parental use of sedating drugs has been linked to an increased risk of SIDS, while breastfeeding has been linked to a decreased risk^​9,10​.

This article will provide an overview of how to risk-assess sedating medicines in breastfeeding, outline safe sleeping practice and the role of the pharmacist. 

Sedating medicines and breastfeeding

It is important to gather sufficient information to enable a fully informed individualised risk assessment^​1​. This includes information about the person taking the medicine (condition being treated, other medicines taken), the infant (age, whether premature, health, any medicines taken and how often they are breastfeeding) and the medicine(s) in question (dose, route, indication)^​1​.

Suitable resources, such as the Specialist Pharmacy Service (SPS), should then be checked for evidence of whether the medicine passes into breast milk, any side effects reported or evidence of harm in breastfed infants and any advisory information, such as infant monitoring. Pharmacokinetic properties can be used to predict whether a medicine is likely to transfer into breast milk^​11​.

Breastfeeding information in the summary of product characteristics (SmPC) and patient information leaflet (PIL) reflect the licensing of the medicine and can be overcautious^​12​. Similarly, some of the BNF statements on the use of medicines during breastfeeding are brief and may be based largely on SmPC statements^​12​. As a result, more specialist resources should be checked if these resources state that a medicine cannot be taken while breastfeeding^​12​.

Recommended specialist resources include:

• ‘Safety in breastfeeding‘, Specialist Pharmacy Service (provided by UKDILAS);
• E-Lactancia;
• Lactmed;
• Medicines A–Z, NHS for patient-friendly advice.

In the authors’ experience, advising to withhold breastfeeding temporarily or to time feeds around medicine doses should be very carefully considered because these strategies can be difficult and stressful for breastfeeding families. These methods are rarely required, but if they are ever used advice also needs to be given to ensure breast milk supply is maintained.

Infant monitoring is a crucial risk-reducing strategy, which can be used to allow breastfeeding to continue, while ensuring that any potential infant side effects are picked up quickly so that the cause can be investigated. Parents should be given patient-friendly, practical advice for symptoms to watch out for and what to do if they suspect side effects but reassured that side effects in breastfed babies are rare and monitoring is usually just a precaution^​13​.

Sudden infant death syndrome 

Previously known as ‘cot death’, SIDS usually affects babies aged under 12 months old^​14,15​. Since the ‘back to sleep’ campaign in 1991, the number of SIDS cases has decreased by 80%, from around 2,000 to around 200 annually^​16​. In 2023, there were 0.14 recorded cases of SIDS per 1,000 live births in England and Wales^​17​.

UNICEF defines bedsharing as “sharing a bed with one or both parents while baby and parent(s) are asleep”. Co-sleeping is defined as when an adult and a baby sleep together on any surface (such as a bed, chair or sofa)^​18​.

A survey of more than 8,500 parents carried out by The Lullaby Trust has shown that 76% have co-slept with their baby at some point in time^​19​. Sleeping in close contact helps babies to settle and can support breastfeeding, which reduces SIDS risk^​8,20​. It is therefore important to acknowledge this but also advise on the risk factors that increase SIDS^​18​.

SIDS usually results from a combination of factors^​14,21​. The risk increases when parents smoke, use alcohol or sedative drugs (medicines or illicit substances), or when babies are born prematurely or of low birth weight^​16​. 

The NHS website has some useful recommendations on sleeping practices to reduce the risk of SIDS, see here for more information. 

Breastfeeding

Overall, breastfeeding reduces the risk of SIDS^​9,10​. A 2017 meta-analysis using data from 2,267 SIDS cases showed that any breastfeeding — whether exclusive or mixed with formula feeding — for at least two months had around half the risk of SIDS. This protection increased the longer the duration of breastfeeding^​10,22​. 

Sedating medication

Most evidence shows that the risk of SIDS increases when drugs or alcohol have been used by either parent when co-sleeping with their infant^{​9,10,23​}. This risk increases from 1 in 3,710 babies (baseline risk) to 1 in 203 babies^​2​. The definition of drug use usually refers to illegal substances or non-prescribed, sedating medications^​23​. However, the evidence is very poor when interpreting the influence of prescribed sedating medication^​24​. It is therefore advisable that co-sleeping should be avoided if a sedating medicine has been taken^​24​.

There is no evidence investigating how breastfeeding protection may offset the increased risk of parental use of sedating medicines or substances. 

How pharmacists can help

Parents should receive advice around safer sleeping soon after they have had their baby, since this forms part of the UNICEF ‘Baby friendly standards’; however, use of a sedative medicine may be initiated later on. Pharmacists can provide advice and reminders around safer sleeping practices when such medicines are initiated, or when the patient is being reviewed.

A sedating medicine can be defined as any medicine known to cause drowsiness as a side effect. To identify whether a medicine is sedating, useful resources include the BNF, the summary of product characteristics (SmPC) and the patient information leaflet (PIL), all of which have information on side effects.

The BNF cautionary and advisory labels (1, 2, 3 and 19) can be helpful but it should be noted that these are not inclusive of all medicines which cause drowsiness (see Box 1^​25​). As a pragmatic approach, it is recommended that medicines known to cause drowsiness or sedation ‘very commonly’ or ‘commonly’ are when the safer sleeping advice should be issued.

Examples of medicines that would fall into this category include opioids, sedating antihistamines and hypnotics.

It can be difficult to know how to approach this topic because it can seem controversial and at odds with the reality of parenting. When advising parents about safer sleeping, it is important that this is handled in a sensitive and non-judgemental way. Harsh messages can invoke feelings of guilt and close down conversations^​18​.  

Healthcare professionals should acknowledge that infants need to feed frequently and it is normal for them to wake and feed during the night, and that this is tiring for parents. Parents should be encouraged to plan ahead where the infant will sleep (including for daytime naps) and how the infant will be cared for if the patient feels drowsy while taking their medicine. This may mean asking another adult to help if possible^​18​.

Example wording might include:

“You may be aware of the advice to avoid falling asleep with your baby, especially on a sofa or armchair to reduce the risk of sudden infant death syndrome. This medicine might make you sleepy and this increases the risk, although it is still very rare. It’s important to try to avoid falling asleep with your baby anywhere, including in your bed, while you’re taking this medicine. It’s normal for babies to wake up to feed in the night, so have a think about how you might look after them if you’re sleepy, to try and make sure you don’t fall asleep with them.”

Case examples

The following cases are presented to demonstrate scenarios that a pharmacist may encounter in primary care and community settings.

Case one

A 36-year-old patient has come into the medical centre for an appointment with the clinical pharmacist. She has recently given birth and has been reviewed by the perinatal mental health community service who has advised that her attention deficit hyperactivity disorder (ADHD) medication can be restarted; they have asked the GP surgery to reinitiate the prescription.

She was previously taking methylphenidate 36mg once daily. The pharmacist asks how everything is going and learns that the infant is now two months old and doing well; however, the patient is really struggling with her ADHD symptoms and would like to start the medication again, but she doesn’t know if she can since she is breastfeeding. She has not previously received any advice about this. 

Methylphenidate is one of the first-line options for the treatment of ADHD in adult patients whose symptoms have not improved despite environmental modifications^​26,27​. Having a newborn infant is a particularly challenging time and it is not uncommon that a patient may want to restart their ADHD medication^​28​.

On further questioning, the pharmacist learns that the infant was born at term and is exclusively breastfed. The pharmacist can see that the patient has had the necessary health checks (e.g. heart rate and blood pressure).

The options the pharmacist has are:

• Advise that methylphenidate use and breastfeeding can go ahead;
• Advise that the methylphenidate should not be restarted because she is breastfeeding;
• Advise that breastfeeding should be discontinued if she wants to take the methylphenidate. 

The pharmacist is aware of the benefits breastfeeding has to both the mother and the infant, and would like to advise that methylphenidate is compatible with breastfeeding. The BNF and SmPC say that methylphenidate is not recommended for use in breastfeeding^​26,29​.  The pharmacist researches this further and looks at specialist resources, and finds that methylphenidate can be used with caution and infant monitoring^{​28,30–33​}.

Although there is very limited evidence regarding the use of methylphenidate during breastfeeding, the data are reassuring. Both immediate-release and slow-release preparations have been studied and show that methylphenidate passes into breast milk in negligible amounts (0.16%–0.70% of the weight-adjusted maternal dose)^{​29,34–37​}. In one case, it was undetectable^​38​.

Methylphenidate has very low oral bioavailability, therefore any that does pass across into breast milk will not be absorbed very well by the infant^​31​. This has been seen when infant serum levels have been measured, finding that the levels of methylphenidate are undetectable (<1 microgram/mL) and generally no side effects or effects on growth and development have been reported^{​34,35,37–40​}. 

Theoretically, methylphenidate could increase or decrease milk supply owing to effects on prolactin levels^​41,42​, but the clinical significance is unknown as there are no published reports of changes to milk supply in those breastfeeding. As a precaution infant weight gain should be monitored.

Modified-release preparations of ADHD medications are preferred for many reasons including their pharmacokinetic profile, convenience and improved adherence^​26,27​. The elimination half-life of methylphenidate in adults following administration is around 3.5 hours, therefore accumulation in the breastfed infant is not a concern^​29​. There would be no requirement to ‘time the feeds’ in any way. 

Methylphenidate is considered a stimulant: insomnia is listed as a very common side effect and symptoms of hyperactivity are common^​29​. However, methylphenidate can also cause drowsiness, with somnolence and fatigue being reported as common and sedation as uncommon^​29​. It is therefore still important that safer sleeping advice is issued, despite methylphenidate classically being thought of as a stimulant. 

After looking at the specialist sources, the pharmacist felt assured that methylphenidate can be used while breastfeeding. They checked the manufacturer’s data and noted that sedation was a concern with this medicine, and therefore issued safer sleeping advice to the patient^​29​. Although side effects are not expected, the pharmacist advised the patient to monitor her infant for the following potential side effects as a precaution:

• Not feeding as well as usual or not putting on weight as you would expect;
• Being irritable;
• Gastro-intestinal disturbances, such as vomiting or diarrhoea;
• Changes to their sleep, which may include insomnia, waking up more often and drowsiness (for example, not waking to feed or falling asleep during feeds);
• Skin rashes;
• Reaching developmental milestones.

The pharmacist advised that if any of these side effects were to occur, the patient should contact a healthcare professional to establish causality first, rather than discontinuing the medicine or stopping breastfeeding. There is a risk of drug withdrawal when methylphenidate is stopped suddenly and this can also be experienced by the infant if the medication or breastfeeding is stopped suddenly^​29​. 

The pharmacist advised that methylphenidate should be initiated at a low dose of 18mg once daily. This was based on knowledge that the lower the dose in breastfeeding, the less risk to the infant and that the patient was re-starting therapy after a break. However, she suggested that the patient come back in one week for review.   

Case two

A patient approached the pharmacy counter and asked to speak to the pharmacist. She was taking sumatriptan 50mg tablets as needed for migraines and also breastfeeding her 5-month-old infant. The patient information leaflet states to avoid breastfeeding for 12 hours after taking a dose and to discard any breast milk expressed during this time^​43​. The patient wanted to ask for advice about this, as she was finding it very difficult.

On further questioning, the patient told the pharmacist that she does not take any other medicines and that the infant is healthy, not taking any medicines and was born at full term. The infant is exclusively breastfeeding. They would not feed from a bottle when this was tried recently and became very unsettled. In addition, the patient also found expressing breast milk difficult, leading to painful engorgement of the breasts. Consequently, this was very distressing for them both and she ended up breastfeeding the infant before the 12 hours had passed.

The pharmacist was aware that the manufacturer’s advice around medicines and breastfeeding is often highly risk-averse and checked additional breastfeeding resources.

Sumatriptan can be taken while breastfeeding as there is some evidence that it only passes into breast milk in very small amounts (up to 3.5% of the weight-adjusted maternal dose)^​44,45​. It also has a poor oral bioavailability (14%), which will limit the amount that the infant can absorb from the milk^​31​. Therefore, it is very unlikely to cause side effects in breastfed infants and none have been reported. The benefits of continuing breastfeeding would far outweigh the risks, especially given the distress caused by interrupting breastfeeding.

The pharmacist advised the patient that infant side effects are unlikely and that in this situation, the harm being caused by avoiding breastfeeding for any time period after taking sumatriptan was unlikely to be offset by any reduction in side effect risk. They explained that the breastfeeding advice in patient information leaflets is sometimes different to the advice of healthcare professionals.

As a precaution, after taking sumatriptan, the infant should be monitored for drowsiness, poor feeding or not waking to feed, irritability, vomiting or any other unusual symptoms, but with reassurance that this is not expected^{​32,43,46​}. If side effects are suspected, report them to a healthcare professional promptly for further investigation.

Breast and nipple pain have been reported in breastfeeding patients after doses of sumatriptan and other triptans, occasionally with reduced milk production. The pain subsided as the drug was eliminated and the authors of the study proposed that it was caused by vasoconstriction in the arteries of the breasts and nipples^​47​. The pharmacist mentioned this to the patient, with advice to also monitor for these effects. 

Drowsiness is a common side effect of sumatriptan^​43​. The pharmacist took this opportunity to provide advice on safer sleeping, noting that the higher risk of SIDS would only apply to the day the sumatriptan was taken owing to the short half-life of around 2 hours^​43​. As a result, extra precaution around falling asleep with the infant should be taken for 12–24 hours after the last dose.