Five common drugs you should avoid using while breastfeeding

Around 92% of people living in the UK have used at least one over-the-counter drug in the past year. While these drugs make it possible to manage symptoms that don’t otherwise require a prescription – such as painkillers for headaches or cough and cold remedies – they aren’t suitable for everyone.

Women who are breastfeeding may not realise some of these over-the-counter drugs should be avoided while breastfeeding. Some of these affect the breastfeeding process itself, while others may have harmful effects on the baby.

Here are five common over-the-counter drugs you should avoid when breastfeeding:

1. Oral decongestants

The average adult experiences around two or three colds each year. While over-the-counter oral decongestants (such as pseudoephedrine or phenylephrine) found in many cold remedies can help relieve a blocked nose, these drugs should be avoided if you’re breastfeeding.

Research shows even just a single dose of an oral decongestant can reduce milk supply. A study showed there was a significant drop in milk production over 24 hours. Repeated use of an oral decongestant could permanently affect the milk supply. This is because oral decongestants reduce prolactin levels – the hormone which drives milk production. This is particularly concerning in mothers who have just started breastfeeding or have low milk production.

Safer alternatives are decongestant nasal sprays which contain xylometazoline and oxymetazoline. These act locally within the nose so are less likely to be absorbed into the body. Saline nasal drops and steam inhalation can also be useful in relieving congestion.

2. Codeine

Painkillers are one of the top sellers in pharmacies.

The painkiller codeine is an opioid which can relieve short-term pain such as headaches or post-operative pain for mothers who have had Caesarean sections or an episiotomy. This kind of high-strength codeine would require a prescription.

But low-strength codeine can be purchase in a pharmacy. Over the counter, it can be found in products containing co-codamol.

Codeine passes into the breastmilk and act on receptors in the baby’s brain and spinal cord. This may lead to sleepiness or breathing problems in the baby. The effect is worse in premature or sick babies – and, in at least one instance, was linked to an infant death.

Safer over-the-counter options for managing pain are paracetamol and ibuprofen at normal doses.

3. Aspirin

Aspirin (also known as acetylsalicylic acid) is a common over-the-counter painkiller which can lower fever and inflammation. It’s found in many cold and flu medicines. Aspirin-based products (such as bismuth subsalicylate) are also found in products used to treat upset stomachs.

But aspirin can pass into breastmilk if used in high doses for long periods of time. Although the exact cause is unknown, aspirin has been linked to Reye’s syndrome in children under 16-years-old. Reye’s syndrome is a rare but serious condition which primarily affects the brain and liver.

Some products containing aspirin may also contain high amounts of caffeine, which is added to help painkillers work better. Caffeine acts on receptors involved in pain regulation in the brain. It’s a stimulant, so when caffeine passes into the breast milk it can lead to a restless baby, especially if they are less than six months old.

Ibuprofen is a safer anti-inflammatory painkiller option to use while breastfeeding. For upset stomachs, over-the-counter drugs containing an antacid or alginate are suitable.

4. Chlorphenamine

Hayfever usually occurs during the summer season. But for some, it can be a year-round concern. Many people will use an antihistamine tablet to treat symptoms.

But products containing chlorphenamine specifically should not be used long-term to treat hayfever or allergy symptoms while breastfeeding. This is because chlorphenamine passes into the breast milk and to the baby. Chlorphenamine can pass into the brain and act on receptors to cause drowsiness. This can result in missed feeds and failure to thrive in the baby.

While occasional, small doses of chlorphenamine may be fine to use, it’s better to reach for non-drowsy antihistamine options such as loratadine or cetirizine. For itchy eyes, eye drops containing sodium cromoglicate are safe to use as these act locally. Similarly, steroid nasal sprays such as beclomethasone also act locally and do not build up in the milk supply.

5. Combined oral contraceptives

Some types of oral contraceptives are now available over the counter as part of the NHS contraception service in pharmacies.

But women who are breastfeeding may not know they should avoid combined oral contraceptive pills containing oestrogen. Oestrogen blocks the hormone prolactin from producing milk. If a mother takes oestrogen-containing contraception, especially in the early months of breastfeeding, it can reduce milk supply, affecting the breastfeeding journey.

Other options, such as the the “mini pill” (which only uses the hormone progesterone) and other non-hormonal measures (such as the copper coil), are safe to use during this time.

Before using an over-the-counter drug, it’s important to read the packaging or leaflet that comes with products to check it’s safe to use while breastfeeding. You can consult online breastfeeding resources for advice on which drugs are safe to use, or speak with your pharmacist or GP if you’re concerned.

In many instances, the effects on milk supply can be reversible, especially with short-term use or small doses.

Dipa Kamdar does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.