Loratadine is a non-sedating antihistamine used for hay fever, allergic rhinitis, hives and itching. It is taken once a day and, for most people, does not cause the drowsiness associated with older allergy medicines.
That is the main reason it is chosen: it works during the day without impairing driving or concentration for most people.
Common side effects of this pharmacy medicine or category
- Headache
- Dry mouth
- Tiredness in some people, despite the non-sedating description
- Nausea
Non-sedating means less sedating rather than never sedating. A minority of people do feel drowsy on it, so find out how it affects you before driving or operating machinery. At higher than recommended doses, drowsiness becomes more likely, which is one reason not to double up when symptoms are bad.
See antihistamine side effects and drowsy compared with non-drowsy antihistamines.
Interactions and duplicate-ingredient risks
Do not take another antihistamine at the same time. Loratadine appears in allergy tablets and syrups, and other antihistamines appear in cold and flu remedies, night-time preparations and some anti-nausea products. Read the active ingredients before combining.
Combination products pair loratadine with a decongestant. Those add jitteriness, a faster heartbeat and raised blood pressure, and are a different proposition from plain loratadine. Check which you have. See decongestant side effects.
Loratadine has relatively few interactions compared with older antihistamines, but mention it if you take medicines affecting heart rhythm, or certain antifungals and antibiotics, which can raise its levels.
Children, pregnancy, older adults and chronic medicine cautions
- Children. Syrups come in different strengths, so dose by the product you have. See children’s antihistamines.
- Pregnancy and breastfeeding. Ask a pharmacist, since some antihistamines are better established than others in pregnancy.
- Older adults. Generally preferable to sedating antihistamines because of lower fall and confusion risk.
- Liver or kidney disease, where a lower dose may be appropriate.
Warning signs and overdose concerns
Get emergency help for difficulty breathing, wheeze, or swelling of the face, lips or throat. As with any allergy medicine, remember that an antihistamine is not the treatment for a severe allergic reaction — that needs emergency care. See anaphylaxis symptoms.
Also seek advice for a fast or irregular heartbeat, marked drowsiness, or any suspected overdose, particularly in a child.
See a doctor if symptoms persist despite treatment, if you need it most days for months, or if you have hives lasting more than six weeks, which warrants assessment rather than continued self-treatment.
Questions to ask a pharmacist before using it
- Is this plain loratadine or a combination with a decongestant?
- Does anything else I take contain an antihistamine?
- What is the right dose for my child?
- Can I take it long term through allergy season?
- Would a nasal spray work better for my symptoms?
Related OTC and medicine-safety guides
- Antihistamine side effects
- Allergy medicine side effects
- OTC medicine side effects
- When to see a doctor about an OTC medicine
- Report an OTC medicine side effect
See also cetirizine and fexofenadine.
Medical Disclaimer: This content is for informational and educational purposes only and does not constitute medical diagnosis, prescription, or professional advice. Always read the patient information leaflet and consult a qualified doctor or pharmacist regarding any medicine or health concern.