Who Should Not Take Zyrtec?: Contraindications and Precautions

October 7, 2025 •

5 min read

According to the FDA, millions of people use oral allergy medications like Zyrtec annually, but it is not safe for everyone. Understanding who should not take Zyrtec is crucial to prevent potentially serious health complications and adverse drug interactions.

Quick Summary

This article explains the critical contraindications and precautions for taking Zyrtec, detailing specific health conditions like kidney or liver disease, potential drug interactions, and special considerations for pregnant or breastfeeding individuals and the elderly. It also covers a recent FDA warning regarding severe itching after long-term discontinuation.

Key Points

Allergic Reaction: Do not take Zyrtec if you have a known allergy to cetirizine, hydroxyzine, or levocetirizine.
Kidney and Liver Impairment: Patients with severe kidney failure should not take Zyrtec, while those with moderate kidney or liver disease may require adjustments to usage determined by a doctor.
Drug Interactions: Avoid alcohol, sedatives, opioids, and other CNS depressants, as these can increase drowsiness and other side effects when combined with Zyrtec.
Caution with Zyrtec-D: The combination product Zyrtec-D should be avoided by individuals with severe heart disease, high blood pressure, glaucoma, or those taking MAOIs.
Pregnant and Breastfeeding Individuals: Both pregnant and breastfeeding individuals should consult a healthcare provider before taking Zyrtec to assess the potential risks and appropriate use.
Elderly Sensitivity: Seniors may be more sensitive to the sedating effects and require careful consideration and potential adjustments to usage as cetirizine is cleared more slowly due to age-related changes in kidney function.
Discontinuation Itching: A potential side effect of long-term daily use is severe itching upon abrupt cessation. Talk to your doctor about gradually tapering the usage of the medication if you have used it long-term.

Zyrtec (cetirizine) is a popular over-the-counter antihistamine used to treat symptoms of allergies such as sneezing, watery eyes, and itching. While effective for many, it is not suitable for everyone, and it's essential to be aware of the specific health conditions, drug interactions, and demographic factors that may make taking it unsafe.

Absolute Contraindications for Zyrtec

Certain pre-existing conditions and allergies make taking Zyrtec strictly inadvisable. If any of the following apply, you should not take this medication without consulting a healthcare provider.

Known Allergy: Anyone who has experienced a prior allergic reaction to cetirizine, the active ingredient in Zyrtec, should avoid it. This also includes individuals with a known allergy to hydroxyzine, a chemically related antihistamine.
Severe Kidney Failure: Since cetirizine is primarily eliminated by the kidneys, patients with severe kidney impairment should not use it. Reduced kidney function can lead to drug accumulation in the body, increasing the risk of side effects.

Medical Conditions Requiring Caution

For some individuals, Zyrtec can worsen existing medical conditions. Always consult a healthcare provider before use if you have any of the following:

Kidney or Liver Disease: Patients with impaired kidney or liver function have a decreased ability to clear the medication from their body, which can lead to higher concentrations and increased risk of adverse effects like drowsiness. Adjustments to usage are typically necessary, and a doctor should determine the appropriate approach.
Urinary Retention Problems: Individuals with an enlarged prostate (Benign Prostatic Hyperplasia) or other issues causing trouble urinating should use Zyrtec with caution. The medication can exacerbate these problems.
Epilepsy or Seizure Risk: Patients with epilepsy or a history of seizures should be cautious, as cetirizine may increase the risk of seizures in susceptible individuals.
Narrow-Angle Glaucoma: This condition involves increased eye pressure. While more of a concern with older antihistamines, caution is advised for those with glaucoma. This is especially true for Zyrtec-D, which contains a decongestant.
Cardiovascular Conditions (Zyrtec-D only): The combination product Zyrtec-D contains pseudoephedrine, a decongestant that can increase blood pressure and heart rate. As such, it should be avoided by people with severe high blood pressure, severe coronary artery disease, or other heart rhythm disorders.

Drug Interactions and Substances to Avoid

Taking Zyrtec alongside other medications or substances can lead to amplified side effects and other dangerous outcomes.

Central Nervous System (CNS) Depressants: Alcohol, sedatives, tranquilizers, opioids, and certain antidepressants can enhance the drowsy and sedating effects of cetirizine. Concomitant use can lead to significant impairment of mental alertness and coordination.
Other Antihistamines: Combining Zyrtec with other antihistamines, such as diphenhydramine (Benadryl), increases the risk of side effects like excessive drowsiness and potentially an overdose. Always check the labels of any cold or allergy medicine to avoid doubling up on active ingredients.
MAOIs (Zyrtec-D only): The decongestant in Zyrtec-D can have a dangerous interaction with Monoamine Oxidase Inhibitors (MAOIs). This combination should not be used, and a period of at least 14 days is required between taking an MAOI and Zyrtec-D.

Comparison of Zyrtec and Zyrtec-D Considerations

It is important to differentiate between standard Zyrtec (cetirizine) and Zyrtec-D, which includes the decongestant pseudoephedrine. The addition of a decongestant introduces new risks for certain individuals.


Feature	Zyrtec (Cetirizine)	Zyrtec-D (Cetirizine + Pseudoephedrine)
Core Active Ingredients	Cetirizine	Cetirizine and Pseudoephedrine
Primary Use	General allergy symptoms (itching, sneezing, runny nose)	Allergy symptoms plus nasal congestion and sinus pressure
Cardiovascular Risks	Minimal risk for most, but caution with other medications	Increased risk of high blood pressure and rapid heart rate due to pseudoephedrine
Diabetes and Thyroid	Generally safe, but monitor with other medications	Caution advised, as decongestants can affect blood sugar and thyroid conditions
Glaucoma	Caution advised	Contraindicated in narrow-angle glaucoma
MAOI Interaction	No interaction	Dangerous interaction, should not be used within 14 days of taking an MAOI
Urinary Retention	Caution advised (enlarged prostate)	Contraindicated if unable to urinate

Special Considerations for Specific Populations

Pregnancy and Breastfeeding

Pregnancy: The FDA has not issued specific safety ratings for many OTC medications but encourages consultation with a healthcare provider. While Zyrtec has been categorized as pregnancy category B, indicating no significant risk in animal studies, it's wise to use the lowest effective amount for the shortest duration necessary, and only under a doctor's supervision.
Breastfeeding: Cetirizine can pass into breast milk. While often considered compatible with breastfeeding for occasional, small amounts, high or prolonged use may potentially decrease milk supply or cause drowsiness in the infant. Breastfeeding mothers should consult a doctor.

The Elderly

Older adults may be more susceptible to the sedating effects of cetirizine. Slower kidney function, even without diagnosed disease, can cause the drug to accumulate in the system. This increases the risk of drowsiness, dizziness, and falls. Using lower amounts is often recommended for the elderly and should be determined by a healthcare provider.

Long-Term Use Discontinuation

In May 2025, the FDA issued a safety warning regarding the risk of severe, widespread itching (pruritus) upon stopping cetirizine or levocetirizine after months or years of daily use. This was reported to be debilitating in some cases. If you use Zyrtec daily long-term and wish to stop, talk to your doctor about gradually tapering the usage to reduce this risk.

Conclusion

While Zyrtec is a safe and effective allergy medication for most people, certain health conditions, drug interactions, and individual circumstances warrant caution or outright avoidance. Individuals with severe kidney failure or a known allergy to cetirizine should not take Zyrtec. Those with milder kidney or liver issues, urinary problems, or epilepsy should consult a doctor before use. The elderly, pregnant, and breastfeeding individuals require special considerations and medical supervision to determine appropriate use. Always inform your healthcare provider of all medications, supplements, and health conditions before starting Zyrtec, and be mindful of the FDA warning regarding severe itching upon discontinuation after long-term use.

For more information on the FDA's warning about severe itching, visit the FDA Drug Safety Communication page.

Disclaimer: This information is for general knowledge and should not be taken as medical advice. Consult with a healthcare professional before starting any new supplement regimen or medication.

Frequently Asked Questions

If you have kidney disease, you should consult a doctor before taking Zyrtec. The medication is primarily eliminated by the kidneys, so decreased function can lead to drug accumulation and side effects. For severe renal impairment, Zyrtec should be avoided, and for moderate impairment, adjustments to usage are recommended and should be determined by a healthcare provider.

Consult a healthcare provider before using Zyrtec if you are pregnant. The American College of Obstetricians and Gynecologists considers cetirizine a relatively safe oral antihistamine during pregnancy, but it is always best to discuss it with a doctor to determine appropriate use.

No, you should avoid drinking alcohol while taking Zyrtec. Alcohol and other central nervous system depressants can increase the risk of drowsiness, dizziness, and impaired judgment when combined with cetirizine.

Individuals with severe high blood pressure, severe coronary artery disease, or narrow-angle glaucoma should avoid Zyrtec-D. It is also contraindicated for those taking MAO inhibitors or who are unable to urinate.

Yes, Zyrtec can interact with other medications. Be cautious when taking it with other antihistamines, sleeping pills, opioid pain relievers, tranquilizers, or sedatives, as these can increase drowsiness and other side effects.

While Zyrtec is generally well-tolerated, older adults may be more sensitive to its side effects, particularly drowsiness and confusion. Because kidney function naturally declines with age, adjustments to usage may be necessary. Always consult a healthcare provider to determine appropriate use.

The FDA has warned that some people may experience severe, widespread itching (pruritus) after stopping long-term, daily use of Zyrtec. This is a rare, but documented withdrawal effect. If you have been taking Zyrtec long-term and wish to discontinue it, speak to a doctor about slowly tapering the usage.