Can I take Antihistamines and Lansoprazole together?
Drug interaction guide
Originally published 12 May 2026
Meets Patient’s editorial guidelines
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There is no significant interaction between most common antihistamines (like cetirizine, loratadine, or fexofenadine) and lansoprazole. However, because lansoprazole reduces stomach acid, it can slightly change how quickly some antihistamines are absorbed, though this is rarely noticeable. If you are using older, 'sedating' antihistamines (like chlorphenamine), you may feel more drowsy, but this is not caused by the lansoprazole itself.
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Why this happens
Lansoprazole is a proton pump inhibitor (PPI) that lowers the acidity of the stomach. Some medications require a specific acid level to dissolve perfectly, but most modern antihistamines are not significantly affected by this change. There is no evidence that these drugs interfere with each other's metabolism in the liver.
What you should do
Back to contentsIt is generally safe to take these two medications together. You do not need to space them apart. If you notice you are feeling unusually sleepy or if your allergy symptoms are not being controlled, speak with your pharmacist or doctor.
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Using other medicines
Back to contentsTaking 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.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
12 May 2026 | Originally published
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