Loratadine

Is loratadine safe?

Yes. Loratadine, sold as Claritin in the US and Clarityn in the UK, is a once-a-day antihistamine for hay fever, dust and pet allergies and hives, and has been sold without prescription in the US since 2002. Serious side effects are very rare, it barely interacts with other medicines, and volunteers took single doses of 160 mg without harm.

We score it 92, ahead of cetirizine (88) and far ahead of the older, sedating diphenhydramine (64). The main thing to watch is not loratadine itself but combination products that add a decongestant.

How much loratadine can you take?

The US Drug Facts doses:

Who	Dose
Adults and children 6 and over	10 mg once a day; no more than 10 mg in 24 hours
Children 2 to under 6	5 mg (5 mL of syrup, or one children's chewable) once a day; no more than 5 mg in 24 hours
Children under 2	Ask a doctor
Liver or kidney disease	Ask a doctor; the UK label starts adults with severe liver impairment on 10 mg every other day

The US label warns that taking more than directed may cause drowsiness. Do not take it if you have reacted to loratadine or desloratadine (Clarinex), its active breakdown product; the two should not be combined.

Loratadine vs cetirizine: which is safer?

Both are second-generation antihistamines with clean records, and for most people either is a reasonable choice. The differences are small but real.

Drowsiness. The New Zealand label says loratadine is no more likely than placebo to cause sedation. In trials, sleepiness was only 1.2% more common than on placebo, and the UK label says driving studies found no impairment. The cetirizine label shows drowsiness rising with dose, to 4.2% on 10 mg in children aged 6 to 11 against 1.3% on placebo. The trials were not head to head and used different age groups, so the comparison is rough.

Stopping. In May 2025 the FDA added a warning about rare, severe itching after stopping long-term cetirizine or levocetirizine. Loratadine labels carry no such warning.

Breastfeeding. The UK label does not recommend loratadine while breastfeeding, and the US cetirizine label says the same for cetirizine. If one antihistamine has not worked for you, a pharmacist can suggest another.

Overdose: a wide margin

Single doses of up to 160 mg, 16 times the daily dose, produced no ill effects in volunteer studies, according to the Health Canada and New Zealand labels. In larger overdoses the reported effects are sleepiness, a fast heartbeat and headache, with treatment aimed at symptoms; activated charcoal may be given. Loratadine is not removed by dialysis.

If a child gets into a pack, call Poison Help on 1-800-222-1222 in the US or NHS 111 in the UK. Mention if it was a Claritin-D pack, because the added pseudoephedrine has its own overdose risks.

Interactions and combination products

Loratadine is broken down by the liver enzymes CYP3A4CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary and CYP2D6. Ketoconazole, erythromycin and cimetidine raise its levels, but the UK label reports no clinically significant changes, including on heart tracings. Alcohol did not add to its effects in performance studies. That is a short list compared with most medicines.

The catch is the 'D'. Claritin-D and its generics add pseudoephedrine, a decongestant that can raise blood pressure and heart rate, keep you awake, and interact with MAO inhibitors. In the US these products are sold from behind the pharmacy counter. Anyone with high blood pressure, heart disease, glaucoma, thyroid problems or difficulty passing urine because of an enlarged prostate should ask a pharmacist before using a 'D' product. For allergies with asthma, doctors sometimes add montelukast, which has different risks of its own.

Who should be careful

Talk to your doctor or pharmacist before using loratadine if you have liver or kidney disease, are pregnant or breastfeeding, or want to give it to a child under 2. Stop and seek help at once for swelling of the face or throat, wheezing or a widespread rash, which are very rare signs of an allergic reaction. If you rely on an antihistamine every day all year, ask a doctor about the cause.

How we scored it

Every factor scores 92 or higher: serious side effects, overdose marginOverdose marginHow far a normal dose is from a harmful one. A wide margin means an accidental extra dose is unlikely to cause serious harm.More in the glossary, interactions, regulatory warnings and track record (all 92), and dependence (95). There is no boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary, safety communication or misuse potential. The points it loses reflect very rare allergic reactions and heart rhythm effects in overdose, and the extra risks of decongestant combinations.