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6 Claritin Side Effects You Should Know About

Dima Cheetany, PharmDTegan Smedley, PharmD, APh
Updated on November 1, 2024

Key takeaways:

  • Claritin (loratadine) is an antihistamine that is available over the counter. Claritin is generally well-tolerated, but it may cause side effects in some people.

  • Common Claritin side effects include headache, dizziness, and digestive side effects such as nausea. Less commonly, some people may experience dry mouth, drowsiness, or fatigue.

  • Claritin side effects are typically mild and can be managed at home. If they become too bothersome, stop taking Claritin and talk to your healthcare team.

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Claritin (loratadine) is one of the most popular allergy medications on the market. It’s available over the counter (OTC), so a prescription isn’t needed to buy it. In fact, you may even have it in your medicine cabinet.

Claritin is an antihistamine that can help provide relief from sneezing, itchy eyes, and other allergy symptoms. It works by blocking histamine. This naturally-occurring chemical in the body causes those pesky allergy symptoms.

Claritin is generally well-tolerated. But while many people take it without problems, side effects are possible.

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Claritin side effects at a glance

Claritin side effects are typically mild and should go away as your body gets used to the medication. Let your healthcare team know if these don’t get better or if they get worse over time.

Common Claritin side effects include:

  • Headache

  • Dizziness

  • Diarrhea

  • Stomach pain

  • Nausea or vomiting

Less commonly, Claritin may cause other mild side effects, such as:

  • Drowsiness

  • Fatigue

  • Dry mouth

Rare but serious Claritin side effects include:

  • Worsening of certain types of glaucoma

  • Allergic reactions

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Below, we’ll discuss six Claritin side effects in more detail.

1. Headache

Headache is one of the most common Claritin side effects. In its original clinical trials from before Claritin was FDA approved, 12% of people taking it reported this side effect. Headache is a possible side effect of all antihistamines. But it’s less likely to happen with second-generation antihistamines like Claritin compared to first-generation antihistamines like Benadryl (diphenhydramine).

There are changes that you can make to help relieve headaches. Drinking enough water, staying active, and optimizing your sleep routine are good first steps to take. There are also OTC medications you can take to help stop occasional headaches, such as Tylenol (acetaminophen) or Advil (ibuprofen).

Headaches may be more noticeable when first starting Claritin. They should become less frequent as you continue taking the medication. If headaches become persistent, talk to your healthcare team to find out if another allergy medication might be a better option for you.

2. Drowsiness

Claritin is considered a non-drowsy antihistamine. This is because it’s less likely to cause drowsiness than older antihistamines like Benadryl. But sleepiness is still possible with Claritin.

Taking Claritin with other medications or substances that cause drowsiness like opioids or alcohol can lead to severe drowsiness. Some people may also be more sensitive to this Claritin side effect, such as older adults.

You should take your first dose of Claritin at home when you don’t have to go anywhere in case you feel sleepy afterwards. Avoid driving or doing activities that require focus until you know how it affects you. Often, drowsiness with Claritin gets better after you’ve been taking it consistently for a bit.

If Claritin is making you feel sleepy, try taking your dose at night. This can help limit daytime drowsiness. If that doesn’t help manage sleepiness, discuss alternative allergy medications with your healthcare team. There are many other non-drowsy options to choose from.

3. Fatigue

Like drowsiness, fatigue (a general lack of energy) is a possible Claritin side effect. But it’s less commonly reported. It’s typically mild and often gets better with continued use of the medication.

Try the following tips to help combat fatigue:

  • Exercise regularly.

  • Rest when your body needs it.

  • Keep a consistent sleep schedule.

  • Eat nutritious meals and snacks that offer whole grains, fruit, and vegetables.

If you continue to feel tired while taking Claritin, talk to a healthcare professional. There may be another cause for it. They may also suggest trying other allergy relief options, such as nasal sprays.

4. Dry mouth

Antihistamines can affect saliva production and cause dry mouth. But, it’s not a very common Claritin side effect, only affecting 3% of people taking it in clinical trials. But if it happens, dry mouth can be uncomfortable.

Chronic dry mouth can also lead to long-term dental problems, such as cavities and mouth infections. So if you notice dry mouth while taking Claritin, you should take steps to manage it.

Some steps to take at home that can help relieve dry mouth include:

  • Increasing the amount of water you drink

  • Sucking on ice cubes or ice chips

  • Chewing on sugar-free gum or sucking on sugar-free candy

  • Avoiding alcohol, including alcohol-based mouthwashes

  • Using saliva substitutes, such as Biotene

Dry mouth from Claritin is typically mild. But if it becomes bothersome or at-home remedies aren’t helping, talk to a healthcare professional for other options.

5. Dizziness

Dizziness is another possible Claritin side effect. As with drowsiness, older adults may be more likely to experience dizziness. And taking Claritin with other medications that cause dizziness may worsen this sensation.

Some at-home remedies that can help in mild cases of dizziness include:

  • Drinking plenty of fluids

  • Getting enough sleep

  • Avoiding getting up quickly from a lying or sitting position

  • Holding onto a sturdy surface when standing to prevent falling

  • Avoiding caffeine and alcohol

If dizziness is severe or causes you to fall, stop taking Claritin and talk to your healthcare team. This amount of dizziness isn’t typical.

6. Digestive side effects, such as nausea

Digestive side effects are also possible with Claritin. These may include upset stomach, nausea, or diarrhea. These side effects should be mild, and you should be able to manage them at home.

Try the following tips with Claritin bothers your stomach:

  • Take Claritin with food.

  • Stay well hydrated.

  • Avoid fried, spicy foods, or high-fiber foods.

  • Eat smaller, more frequent meals.

  • Try ginger or peppermint tea.

If these changes don’t seem to help, there are OTC upset stomach medications available, such as Pepto-Bismol (bismuth subsalicylate). If stomach side effects continue with Claritin, let a healthcare professional know. There may be another cause for your symptoms.

When should you contact a healthcare professional about Claritin side effects?

Severe Claritin side effects aren’t typical, and the medication is generally well tolerated. Often, side effects get better with time. And small lifestyle changes, as discussed above, can help relieve them. If Claritin side effects don’t go away, contact a healthcare professional to discuss alternative medications.

Call 911 or get immediate medical help if you have any of the following symptoms of a severe allergic reaction:

  • Skin rash

  • Hives

  • Swelling of the face, lips, tongue, or throat

  • Trouble breathing

  • Wheezing

  • Hoarseness

Frequently asked questions

Does Claritin keep you awake?

No, Claritin shouldn’t keep you awake. If anything, it’d be more likely to cause drowsiness (although this is rare). But taking Claritin-D (loratadine / pseudoephedrine) can keep you awake. This is because the pseudoephedrine portion of Claritin-D can cause trouble sleeping.

Does Claritin raise blood pressure?

No, Claritin isn’t known to raise blood pressure. This makes it a safe option for people with high blood pressure or other heart problems. But if you’re taking Claritin-D, it can affect your blood pressure. The pseudoephedrine component of this combination product causes high blood pressure as a side effect.

The bottom line

Common Claritin (loratadine) side effects include headache, dizziness, and digestive side effects such as nausea. Less commonly people may experience drowsiness, fatigue, or dry mouth. Serious complications are very rare with Claritin. Contact a healthcare professional if any Claritin side effects become too bothersome. There are several other allergy relief options that may be a better fit for you.

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Why trust our experts?

Dima Cheetany, PharmD
Dima Cheetany is a clinical pharmacist, clinical instructor, and academic detailer at the University of Illinois at Chicago. She graduated with her Doctor of Pharmacy from Roosevelt University College of Pharmacy in 2016.
Christina Aungst, PharmD
Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.
Tegan Smedley, PharmD, APh
Tegan Smedley, PharmD, APh, has 10 years of experience as a pharmacist. She has worked in a variety of settings, including retail, hospital, and ambulatory care.
View All References (1)

Sidhu, G., et al. (2023). Loratadine. StatPearls.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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