Can I take antihistamines while pregnant?
Drug interaction guide
Originally published 30 Apr 2026
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While many antihistamines are considered safe, some older types or high doses may affect the baby, and certain versions contain decongestants that must be avoided. Taking any medication during pregnancy requires a balance between your comfort and the baby's development.
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Why this happens
Antihistamines cross the placenta, meaning they reach the baby's bloodstream. Some older 'sedating' antihistamines may cause irritability or tremors in newborns if taken close to birth. Additionally, some multi-symptom allergy tablets contain stimulants (decongestants) that can restrict blood flow to the placenta.
What you should do
Always speak to your GP, pharmacist, or midwife before taking any antihistamine while pregnant. Loratadine and cetirizine are usually the preferred 'non-drowsy' options if treatment is necessary. Avoid 'all-in-one' cold and flu remedies, as these often contain ingredients that are not safe during pregnancy.
Important precautions
Pregnancy (Late Stage)
Taking sedating antihistamines close to the time of delivery can cause the newborn baby to experience irritability, tremors, or poor feeding. These should be avoided in the third trimester unless specifically prescribed.
More about Chlorphenamine (Piriton)
More about Promethazine (Phenergan)
More about Hydroxyzine (Atarax)
More about Alimemazine (Vallergan)
Food and drink warnings
Alcohol
It is best to avoid or strictly limit alcohol when taking antihistamines. Alcohol can significantly increase the sedative effects (drowsiness and dizziness) of these medicines, making you more likely to have an accident or fall. This is especially dangerous with older 'sedating' antihistamines, but can also happen with newer 'non-drowsy' types.
Fruit Juices (Grapefruit, Orange, Apple)
Do not drink grapefruit, orange, or apple juice while taking fexofenadine. These juices can significantly reduce the amount of medicine your body absorbs, making the treatment less effective. It is best to take fexofenadine with water.
More about Fexofenadine (Allegra)
Using other medicines
Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
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