Loratadine

What is loratadine?

Loratadine, most commonly known as Claritin, is a second-generation, long-acting antihistamine. It is used to treat allergic symptoms, which are triggered by a substance in the body called histamine. Loratadine relieves these symptoms by blocking the action of histamine within the body.¹

It does not cross the blood-brain barrier, so it is less sedating than first-generation antihistamines.²

What conditions is loratadine used to treat?

Loratadine is approved by the US Food and Drug Administration (FDA) for the treatment of seasonal allergies, and a type of allergic skin rash called chronic idiopathic urticaria in adults and children aged two years and older.³

Specifically, loratadine provides relief from the following allergy-related symptoms:

• Red, watery, itchy eyes

• Sneezing

• Itchy nose and throat

• Runny nose

Urticaria is a raised, itchy rash. You may know the characteristic welts as hives. Loratadine is indicated for the treatment of chronic, unexplained urticaria in patients two years and older. While it doesn’t prevent hives or cause them to disappear, loratadine relieves the following symptoms associated with urticaria:

• Itching

• Redness

Dosage forms and strengths

Loratadine is available in the following forms to be taken orally: tablet, rapidly disintegrating tablet, chewable tablet, liquid-filled gel capsule, and liquid solution.⁴ ⁵

The available strengths of the different forms are as follows:

• Tablet: 10mg

• Rapidly disintegrating tablet: 5mg, 10mg

• Chewable tablet: 5mg

• Gel capsule: 10mg

• Liquid solution: 1mg/mL

Typical recommended dosage⁶

• Adults and children aged six and older: 10mg once a day or 5mg twice a day as needed. The maximum recommended dose is 10mg in a 24-hour period.

• Children between two and five years old: 5mg once daily as needed. The disintegrating tablet is usually not recommended for this age group.

• Patients with kidney or liver impairment may need to wait 48 hours between doses initially.

How do you take loratadine?

It is recommended to take loratadine on an empty stomach, but you may choose to take it with or without food.⁷

Loratadine capsules or tablets can be swallowed whole with water. 

You can also take a rapidly disintegrating tablet by holding it under your tongue until it dissolves, then swallowing the remnants with water.

If you opt for the liquid solution, use a measuring device specifically intended for measuring medications. Household spoons are not sufficiently precise.

Seeing results

Loratadine starts working quickly. You should experience an improvement in symptoms within the first three hours of taking it, and it continues to work for 24 hours.⁸

According to a study in the journal Allergy, Asthma, and Clinical Immunology, significant improvements in symptoms were usually seen within 75 minutes of taking loratadine in tablet form. Earlier studies showed the capsule form had a slower onset of 180 minutes.⁹

Who should not take loratadine?

This medication should not be taken by children under two years old, as it can potentially cause seizures due to its effects on the central nervous system.¹⁰

Patients who should be cautious and speak to a doctor before taking loratadine include those with the following conditions:¹¹

• Asthma or COPD

• Phenylketonuria (PKU)

• Liver disease

• Chronic kidney disease or kidney failure

Potential side effects of loratadine

Loratadine is considered to be safe and effective, but some people experience side effects. Most of them are mild and resolve without treatment.¹² ¹³

Common and less severe side effects of loratadine include the following:

• Headache

• Nose bleeds

• Sore throat or mouth sores

• Stomach pain, nausea, vomiting

• Red or itchy eyes

• Diarrhea

• Fatigue, drowsiness

• Nervousness, weakness

Less commonly, the following side effects may occur, some due to the anticholinergic effects of loratadine:¹⁴

• Mydriasis (dilated pupils)

• Sedation

• Xerostomia (dry mouth)

• Difficulty speaking

• Nervousness

• Restlessness, hyperactivity

• Rapid heart rate

• Urinary retention

• Sweating, skin flushing

Other reported adverse effects include the following:¹⁵ ¹⁶

• High or low blood pressure

• Heart palpitations, abnormal heart rhythm

• Constipation/diarrhea

• Decreased libido

• Difficulty concentrating

• Anxiety, irritability

• Cough, difficulty breathing

• Nasal dryness

• Photosensitivity

• Muscle aches, joint pain

• Leg cramps

These lists of potential side effects are not exhaustive. Speak with your doctor if you experience anything unusual while taking loratadine. Seek emergency medical assistance if your symptoms are severe.

Overdose

If you or someone in your care has taken more than the recommended dose of loratadine or you notice severe adverse effects after taking it, seek immediate medical care by going to your nearest emergency department or calling 911 or the National Poison Control hotline at 1-800-222-1222.

Symptoms of an overdose may differ by age.¹⁷

In adults:

• Excessive sleepiness

• Rapid heartbeat

• Headache

In children:

• Involuntary movements

• Rapid or irregular heartbeat

Allergy information

Serious allergic reactions to loratadine are rare. However, if you experience any of the following symptoms after taking it, speak with your doctor. If your symptoms are severe, seek urgent medical care. 

Signs of a drug allergy may include the following:

• Hives, itching

• Difficulty breathing or swallowing

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

• Vomiting

• Loss of consciousness

Long-term use of loratadine

There are no safety concerns with the long-term use of loratadine. However, it's intended to be used as needed, so it is best to take it only when allergic symptoms are present. In addition, because it is fast-acting, there is no need to maintain regular use for it to be effective.

Loratadine in pregnancy and breastfeeding

The US FDA designated loratadine as a pregnancy category B drug. There are not enough studies on human subjects to prove it's safe during pregnancy, but it has been shown to be safe in animal studies.¹⁸

Because there isn't enough evidence to determine that loratadine is safe during pregnancy, it should only be taken if its benefits outweigh the potential risks. Speak with your doctor about the risks and benefits in your case.

Loratadine and its metabolite have been shown to pass easily into breast milk. Speak with a trusted medical professional if you plan to take this medication while breastfeeding.¹⁹

Missed doses

If you miss a dose of loratadine, you can skip the dose or take it when you remember. Be sure to adjust any subsequent doses, so you don't exceed the recommended amount in a 24-hour period. If you aren't experiencing any symptoms, it's simplest to skip the forgotten dose and take loratadine again when you need it.

Drug interactions

There is no evidence of dangerous and significant drug interactions. However, you should check with your doctor if you take any medication that affects the CYP450 enzyme pathway because you may need to use a different antihistamine instead.²⁰

Loratadine may interact with the following medications:²¹

• Other allergy medicines, including olopatadine intranasal (Patanase)

• Anti-seizure medicines, such as carbamazepine (Tegretol)

• Gastrointestinal medicines, including cimetidine (Tagamet) and metoclopramide intranasal (Gimoti)

• Antibiotics, including clarithromycin (Biaxin), erythromycin, rifampin, and rifabutin (Mycobutin)

• Cancer drugs, such as everolimus (Zortress, Afinitor), erdafitinib (Balversa), sotorasib (Lumakras), and tepotinib (Tepmetko)

• Antidepressants, such as isocarboxazid (Marplan) and tranylcypromine (Parnate)

• Migraine medicines, including lasmiditan (Reyvow)

• Mavacamten (Camzyos)

This is not a complete list of the medicines that might interact with loratadine, so be sure to tell your doctor everything you’re taking. If you take any of the medications listed above, speak with your doctor about how or if you can take loratadine safely.

Can I drink alcohol while taking loratadine?

In a study looking at the effects of combining loratadine and alcohol, researchers found that loratadine did not potentiate the effects of alcohol. However, because sedation is a known side effect of both substances, you should exercise caution if you consume alcohol while taking loratadine. Assess your body’s handling of loratadine before you consume alcohol and engage in any activities requiring alertness.²²

What to discuss with your doctor before starting loratadine

To ensure you have the most effective treatment plan, it’s good to bring up the following topics with your doctors before starting loratadine:

• The allergy symptoms causing you the most trouble

• Any other medications (prescribed or over-the-counter), vitamins, supplements, and herbs you take regularly or occasionally

• Your medical history, particularly any liver or kidney disease

• Any allergies to medications

Stopping loratadine

There are no withdrawal concerns with loratadine. It’s intended to be taken as needed, so you can stop using it anytime.

Drug approval history

Loratadine, under the brand name Claritin, was approved by the FDA in 1993. The topic of some controversy in its first years on the market, Claritin was one of the first medications promoted using direct-to-the-consumer advertising.²³ ²⁴

In 1998, the FDA approved a petition to make loratadine available without a prescription. By 2002, Claritin made its original product available over the counter.²⁵

Tips for taking loratadine

To get the best results, follow these tips:

• Take the medication at the same time daily to ensure that you don't exceed the 24-hour dose recommendation.

• It's best to take loratadine on an empty stomach, as food can interfere with absorption, but it will also work when taken with food.

• Take the capsules and tablets with water.

• If you use rapidly disintegrating tablets, allow one to dissolve under the tongue. You can swallow what is left with water.

• Monitor children to ensure they don't take more than the recommended dose for their age, especially if they like the taste of chewable tablets or syrup.

Frequently asked questions

Does loratadine make you sleepy?

This medication causes less sleepiness than many other antihistamines. However, some people do experience slight drowsiness. This side effect may improve or resolve with continued use.²⁶

Does loratadine raise blood pressure?

High blood pressure has been reported but is not a common side effect of loratadine. In some cases, the drug can cause lower-than-normal blood pressure readings. If you’re concerned about your blood pressure while taking loratadine, speak with your doctor.

When is the best time to take loratadine?

This depends on when you experience the most severe allergy symptoms. Because it is formulated as a once-daily antihistamine, loratadine reaches its peak effectiveness about 8–12 hours after you take it.²⁷

If you struggle with allergies in the morning, you may consider taking it the night before. If you experience the worst symptoms at night, it might be best to take it in the morning.