Cetirizine tablets tend to work slightly faster than Loratadine, but are more likely to make you feel sleepy. Both medications are taken daily, relieving symptoms for 24 hours, and are proven to be safe and effective in treating hay fever and allergy symptoms.
This detailed overview explains the key differences between Cetirizine and Loratadine so you can confidently manage your symptoms at home.
Factor | Cetirizine | Loratadine |
Time it takes to work | 20 – 60 minutes | 1 – 3 hours |
How long it lasts for | 24 hours | 24 hours |
Drowsiness risk | Low | Low |
Adult dosage | 1 tablet daily | 1 tablet daily |
Most common side effects | Diarrhoea, dry mouth, drowsiness, fatigue | Headache, drowsiness, trouble sleeping, increase in appetite, nausea |
Can it be used long-term? | Unlikely to cause harm long-term | Unlikely to cause harm long-term |
Does it interact with other medicines? | Yes | Yes |
NHS guidelines state the usual dosage for adults is 10 mg once daily, with a maximum of 10mg per day, and a lower dose for children based on age.
It’s important to remember to stick to the correct dosage because exceeding this can lead to increased sedation, headaches, dry mouth, and even more severe effects like heart issues or confusion.
If cetirizine does not relieve your symptoms after a couple of days, or if you experience severe side effects, speak to your doctor. They may suggest adjusting your dosage, trying a different antihistamine, or exploring other treatment options if necessary.
Loratadine 10mg is taken once a day as recommended on the NICE guidelines. This dosage is for most adults and children over 6 years old.
If you take more than the recommended dosage, side effects including heart palpitations, dry mouth and drowsiness can occur. You should avoid drinking alcohol too because this can increase the sedative effects.
Side effects shouldn’t last for more than a few days, however it’s best to speak to your doctor for advice if they do.
One in ten people experience some drowsiness and sleepiness after taking Cetirizine. It’s a very common side effect that usually subsides once the medication is out of your system.
There are additional side effects to be aware of too, such as:
Serious side effects are rare when taking cetirizine.
Like cetirizine, feeling sleepy is the most common side effect of Loratadine. You may also experience:
These side effects are usually mild. It’s worth making a note of any that you experience so that if they do not stop after a few days, you can inform your doctor or pharmacist. You can also report side effects using the MHRA yellow card system.
When taken at the recommended dosage, Cetirizine is considered safe to use long-term, particularly for chronic conditions like allergic rhinitis or chronic urticaria (hives).
Long-term use requires more consistent monitoring to ensure that you’re still using the correct treatment for your symptoms.
Some medications do cause interactions, which can affect your protection from hay fever symptoms and increase side effects. You should speak to your doctor if you take any of the following:
Loratadine tends to be well tolerated by most people when used for extended periods, but there is a possibility of rare side effects.
It is not known to cause withdrawal or dependence symptoms.
Some people, for example those with liver or kidney disease, may need to adjust their dosage and be monitored. Mild bouts of dry mouth and eyes, as well digestive discomfort can occur with long-term usage.
Cetirizine and Loratadine are the most affordable options when it comes to buying antihistamine tablets from Chemist Click. It is the same price for a one-month course of either treatment and will be delivered directly to your door. Cetirizine and Loratadine are readily available and easy to buy online or from your local high street pharmacy.
There is specific safety information that you should be aware of, whether you are taking antihistamines for the first time, or using them on a long-term basis to avoid and minimise your risk of adverse effects.
There are also times when you need to share information about your health with your doctor.
You should always follow the medical advice and refer to the patient information leaflet. If you have any doubts, it’s best not to take it and seek advice first.
The best treatment is highly dependent on your specific needs including your symptoms, severity and lifestyle. It may be helpful to refer to the most common queries when it comes to choosing the best hay fever medication:
It takes a few easy steps with Chemist Click to be on your way to alleviating bothersome hay fever symptoms thanks to our wide selection of antihistamine treatments and steroid sprays.
Whether you’re looking for strong hay fever tablets such as Cetirizine (Zyrtec) and Fexofenadine Tablets or non-drowsy antihistamines such as Loratadine (Claritin), our team of in-house pharmacists are on hand to advise you on the best treatment for your symptoms.
No, this is not recommended because it can increase your risk of side effects such as drowsiness and fatigue. If you find one is not improving your hay fever symptoms, contact your doctor so they can assess your dosage and advise on the best treatment for your needs.
It is one of the stronger antihistamines for the treatment of hay fever and allergies, but there are stronger alternatives such as diphenhydramine (Benadryl). This is a first generation antihistamine which causes stronger sedative effects.
Some of the strongest second-generation antihistamines for consistent, non-sedating relief are Cetirizine or Levocetirizine. Antihistamines such as Fexofenadine and Desloratadine are also strong but typically less effective than cetirizine for severe reactions.
Drowsiness is the most common side effect of Loratadine affecting 1 in 100 people.
This depends on your individual needs. Cetirizine may be better for you if you want an antihistamine that works fast, Loratadine may be better for you if you want to treat itchy skin and hives.
Cetirizine is more likely to cause drowsiness, but it is possible to experience this with either antihistamine.
NHS.UK (n.d). Cetirizine. Retrieved 12th February 2025, from: https://www.nhs.uk/medicines/cetirizine/
Bnf.nice.org (n.d). Loratadine, indications and drug use. Retrieved 12th February 2025, from: https://bnf.nice.org.uk/drugs/loratadine/#indications-and-dose
NHS.UK (n.d). Allergic Rhinitis. Retrieved 12th February 2025, from: https://www.nhs.uk/conditions/allergic-rhinitis/%C2%A0
Bmj.com (April 2000). Sedation with “non-sedating” antihistamines: four prescription-event monitoring studies in general practice. Retrieved 13th February 2025, from: https://www.bmj.com/content/320/7243/1184%C2%A0
Whilst all of our content is written and reviewed by healthcare professionals, it is not intended to be substituted for or used as medical advice. If you have any questions or concerns about your health, please speak to your doctor.