Loratadine: what it treats, how to take it, side effects
Last updated September 3, 2026.
Loratadine is an antihistamine used to relieve allergy symptoms. It works by blocking histamine, the substance in the body that causes sneezing, itching, and watery eyes. You may know it as Claritin or Alavert.
What does it treat?
Loratadine treats sneezing, runny nose, itching of the nose or throat, and red, itchy, or watery eyes - the standard allergy symptom list. MedlinePlus notes it has also been used for itching and redness caused by hives. For deeper congestion, it also comes in combination products with the decongestant pseudoephedrine (Claritin-D), which follow different rules.
How do you take it?
Loratadine comes as a tablet, chewable tablet, capsule, liquid, and a rapidly dissolving tablet. The label directs adults and children 6 and over to take one tablet once a day, with or without food, and never more than one tablet in 24 hours. Children under 6 and people with liver or kidney disease should ask a doctor first. If you use the dissolving tablet, peel back the foil rather than pushing the tablet through, place it on your tongue right away, and let it dissolve - water is optional. If you miss a dose, take it when you remember unless the next one is almost due; never take two at once.
Side effects to know
- Common: headache, drowsiness, and tiredness.
- Serious: signs of an allergic reaction to the drug itself - rash, hives, itching, difficulty breathing or swallowing, or swelling of the eyes, face, lips, tongue, or throat. Stop taking it and call your doctor immediately if these appear.
Who should not take it?
Anyone who has had an allergic reaction to loratadine should not take it. People with kidney or liver disease need a doctor's guidance on dosing, and the chewable tablets may contain aspartame, which matters for people with phenylketonuria (PKU). Tell your doctor if you are pregnant, planning pregnancy, or breastfeeding before starting.
When is it an emergency?
An allergic reaction to loratadine is the emergency to know: swelling of the face, lips, tongue, or throat, or trouble breathing or swallowing means calling 911. For an overdose, call Poison Control at 1-800-222-1222, or 911 if the person has collapsed, had a seizure, or cannot be awakened. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Does loratadine make you drowsy?
It can, though it is considered a less-sedating antihistamine. MedlinePlus still lists drowsiness and tiredness among its common side effects, so pay attention to how you feel on the first few doses.
Can I take loratadine with food?
Yes. MedlinePlus says loratadine is taken once a day with or without food - whatever fits your routine.
What is the difference between Claritin and Claritin-D?
Both are brand products built on loratadine, but Claritin-D adds pseudoephedrine, a decongestant. MedlinePlus lists these as separate combination products, and the combination follows different rules than loratadine alone - read the package label or ask your pharmacist which one fits your symptoms.
What should I do if I miss a dose?
Take it as soon as you remember, unless it is almost time for the next dose - then skip the missed one and return to your schedule. Do not take a double dose to catch up.
Is loratadine safe with kidney or liver disease?
The FDA label directs people with liver or kidney disease to ask a doctor before using loratadine, because the drug is cleared more slowly in those conditions. Your doctor may adjust how often you take it.
Can I take loratadine while pregnant?
MedlinePlus advises telling your doctor if you are pregnant, planning to become pregnant, or breastfeeding before taking loratadine, and calling your doctor if you become pregnant while on it. That conversation - not the package - is the right place to settle it.