Who Should Not Take Claritin? Essential Safety Guidelines and Warnings

October 7, 2025 •

5 min read

According to the manufacturer and clinical data, while Claritin is an effective and generally safe over-the-counter antihistamine, certain individuals with pre-existing conditions, such as liver or kidney disease, should consult a healthcare provider before use to ensure proper dosing and avoid complications.

Quick Summary

This guide explains key contraindications and precautions for taking Claritin, covering health conditions like kidney or liver disease, drug interactions, and special populations.

Key Points

Hypersensitivity: Do not take Claritin if you are allergic to loratadine, desloratadine, or any other ingredients.
Pre-existing Conditions: Use caution with liver disease, kidney disease, or severe asthma, and consult a doctor for possible dosage adjustments.
Claritin-D Contraindications: Avoid Claritin-D if you have severe high blood pressure, heart disease, glaucoma, urinary retention, or are taking MAOIs.
Drug Interactions: Do not combine Claritin with other antihistamines, alcohol, or medications that cause drowsiness. Certain antibiotics and antifungals can also cause adverse interactions.
Special Populations: Older adults may be more susceptible to side effects. Pregnant or breastfeeding women and parents of young children should consult a doctor before use.
Phenylketonuria (PKU): Certain chewable Claritin formulations contain phenylalanine and should be avoided by individuals with PKU.

Absolute Contraindications for Claritin

While Claritin (loratadine) is a second-generation antihistamine known for being non-drowsy, it is not suitable for everyone. A primary contraindication is a known hypersensitivity or allergic reaction to loratadine, its active metabolite desloratadine, or any other ingredient in the product. In such cases, taking the medication could lead to a severe allergic reaction, including hives, swelling, or difficulty breathing.

Additionally, some formulations of Claritin, such as the orally disintegrating tablets, may contain phenylalanine as an inactive ingredient. This makes them contraindicated for individuals with phenylketonuria (PKU), a rare genetic disorder where the body cannot process the amino acid phenylalanine. Patients with PKU must carefully check the ingredients list and consult their doctor before using any medication containing this substance.

Claritin-D: Specific Warnings for the Decongestant Component

It is critical to distinguish between standard Claritin (loratadine only) and Claritin-D, which includes the decongestant pseudoephedrine. The pseudoephedrine component introduces a new set of contraindications and warnings that make Claritin-D unsafe for many individuals. Claritin-D should be avoided by people with the following conditions due to the stimulant effects of pseudoephedrine:

Severe high blood pressure (hypertension): Pseudoephedrine can increase blood pressure and heart rate.
Severe coronary artery disease: This can cause adverse cardiac events.
Narrow-angle glaucoma: The medication can increase intraocular pressure.
Urinary retention or difficulty urinating: Pseudoephedrine can worsen symptoms in those with an enlarged prostate or other urinary problems.
Taking Monoamine Oxidase Inhibitors (MAOIs): Claritin-D should not be used by patients taking MAOIs or within 14 days of stopping MAOI therapy, as this can cause dangerous increases in blood pressure.

Precautions for Patients with Underlying Health Conditions

Patients with certain medical issues should use Claritin with caution and under medical supervision:

Kidney or Liver Disease: Since loratadine is processed by the liver and excreted by the kidneys, patients with severe liver or kidney dysfunction may have reduced clearance of the drug. This can cause the medication to build up in the body, increasing the risk of adverse effects. Healthcare providers may recommend a reduced or alternate-day dose.
Asthma or COPD: While typically a safe option, second-generation antihistamines have mild anticholinergic effects that may worsen some respiratory symptoms in patients with severe asthma or chronic obstructive pulmonary disease (COPD).
Heart Problems: For standard Claritin, cardiac events are rare but have been reported with overdose. For Claritin-D, the pseudoephedrine component can cause a fast or irregular heartbeat, which is especially risky for those with pre-existing heart conditions.
Epilepsy: In rare cases, antihistamine overdose can lead to seizures. Patients with a history of epilepsy should discuss use with a doctor.

Important Drug Interactions to Avoid

To prevent serious side effects, be aware of these potential interactions when taking Claritin:

Other Oral Antihistamines: Do not combine Claritin with other oral antihistamines, including older, more sedating ones like diphenhydramine (Benadryl) or nighttime cold/flu medications containing antihistamines. This increases the risk of side effects such as drowsiness and dry mouth.
CNS Depressants and Alcohol: Combining Claritin with alcohol or other CNS depressants (opioids, muscle relaxers, sleeping pills) can increase drowsiness and dizziness. Although Claritin is generally non-drowsy, the risk is heightened in combination with these substances.
Certain Antibiotics and Antifungals: Medications like erythromycin, clarithromycin, and ketoconazole can interfere with the liver enzymes that metabolize loratadine. This can lead to increased concentrations of loratadine in the blood and a higher risk of side effects.
Cimetidine: The heartburn medication cimetidine can also inhibit loratadine's metabolism, raising its plasma concentration.
MAOIs (with Claritin-D): As mentioned, this combination is contraindicated with Claritin-D.

Special Population Considerations

Specific groups of people should take extra precautions when considering Claritin:

Pregnancy and Breastfeeding: Claritin is generally considered safe during pregnancy and is often a preferred antihistamine. However, as with any medication, it's best to consult a healthcare professional, especially during the first trimester. For breastfeeding mothers, a small amount of loratadine passes into breast milk, and it's recommended to use minimal doses for short periods. Claritin-D should be avoided during breastfeeding as pseudoephedrine can decrease milk supply.
Older Adults: Individuals over 60 may be more sensitive to the side effects of antihistamines, including drowsiness, dizziness, and confusion. Higher doses can also increase the risk of cardiotoxicity in this population. A lower dosage might be necessary.
Children: Claritin should not be given to children under certain ages without consulting a doctor first. Dosage is weight-based, and giving too much can cause agitation or seizures.

Understanding the Risks: Claritin vs. Claritin-D

Understanding the differences in formulation and potential risks is crucial for safe medication use.


Feature	Standard Claritin (Loratadine)	Claritin-D (Loratadine & Pseudoephedrine)
Active Ingredients	Loratadine	Loratadine and Pseudoephedrine
Primary Use	Non-drowsy relief for allergy symptoms (sneezing, itching, watery eyes).	Relief of allergy symptoms plus nasal congestion and sinus pressure.
Cardiovascular Risk	Low risk at recommended doses; rare with overdose.	Increased risk of elevated blood pressure and heart rate due to decongestant.
Drowsiness Risk	Minimal risk of drowsiness.	Potential for insomnia due to stimulant effect of pseudoephedrine.
Special Contraindications	Hypersensitivity to loratadine or desloratadine; some formulations contraindicated for PKU.	Allergic reactions, severe hypertension, severe coronary artery disease, glaucoma, urinary retention, MAOI use.
Use in Breastfeeding	Generally considered safe, but use with caution and minimal dose.	Avoid, as pseudoephedrine may decrease milk supply.

What to Do in Case of Overdose or Side Effects

If you accidentally take more Claritin than directed, or experience unusual or severe side effects, contact a healthcare provider or Poison Control immediately. Symptoms of overdose can include headaches, rapid heartbeat, agitation, and extreme drowsiness. Some individuals may be more sensitive to common side effects like headache, dizziness, or fatigue, and should discuss alternative options with their doctor.

Conclusion: Always Consult Your Healthcare Provider

While over-the-counter availability makes Claritin seem universally safe, it is vital to remember that not everyone should take it without caution. Key groups who need to consult a healthcare provider include those with liver or kidney disease, older adults, and pregnant or breastfeeding individuals. Furthermore, the addition of pseudoephedrine in Claritin-D creates a significantly different risk profile, with specific contraindications related to heart conditions, high blood pressure, and drug interactions. Reading the product label carefully and discussing any health concerns with a medical professional is the most responsible way to manage allergies safely.

For more comprehensive information on loratadine and its pharmacology, please refer to authoritative resources like the National Institutes of Health (NIH).

Frequently Asked Questions

Individuals with a known allergy to loratadine or desloratadine should not take Claritin. People with severe liver or kidney disease should consult a doctor for potential dosage adjustments. Those with phenylketonuria (PKU) should avoid chewable forms that contain phenylalanine.

Standard Claritin (loratadine) typically does not affect blood pressure. However, you should not take Claritin-D (which contains the decongestant pseudoephedrine) if you have severe high blood pressure, as it can cause an increase in blood pressure.

Claritin can interact with other oral antihistamines, alcohol, sedatives, and certain antibiotics (e.g., erythromycin, clarithromycin) and antifungals (e.g., ketoconazole). You should avoid mixing these to prevent increased side effects like drowsiness.

Claritin (loratadine) is generally considered safe during pregnancy, but you should always consult a healthcare provider first. While a small amount passes into breast milk, it's considered safe for infants. Claritin-D should be avoided while breastfeeding, as it can reduce milk supply.

Loratadine is metabolized by the liver and excreted by the kidneys. If these organs are not functioning properly, the medication can accumulate in the body, increasing the risk of adverse effects. A doctor may need to adjust the dosage.

The main difference is the pseudoephedrine in Claritin-D. This decongestant makes it unsafe for individuals with severe hypertension, heart disease, glaucoma, urinary retention, or for those taking MAOIs.

Claritin has age restrictions, particularly for young children. For example, chewable forms are not for children under 2, and some tablets are not for children under 6 without a doctor's advice. Dosage must be carefully followed based on the child's age.