What drugs should not be taken with levocetirizine?

October 8, 2025 •

4 min read

Over 18 million prescriptions for antihistamines are dispensed each year, but many people are unaware of potentially dangerous drug interactions. It is crucial to understand what drugs should not be taken with levocetirizine, a common second-generation antihistamine, to prevent side effects like excessive drowsiness and impaired judgment.

Quick Summary

Certain substances, including alcohol and central nervous system (CNS) depressants like sedatives and opioids, should be avoided when taking levocetirizine. Interactions can increase side effects like drowsiness and coordination issues.

Key Points

Avoid CNS Depressants: Do not combine levocetirizine with alcohol, sedatives, opioids, or benzodiazepines, as this can lead to excessive and dangerous sedation and impaired motor skills.
Be Cautious with Other Antihistamines: Taking multiple antihistamines, especially first-generation ones, concurrently can cause amplified drowsiness and side effects.
Consult a Doctor for Specific Medications: Inform your doctor if you take Ritonavir, Theophylline, or any Monoamine Oxidase Inhibitors (MAOIs), as these have known interactions with levocetirizine.
Exercise Caution with Kidney Disease: Levocetirizine is contraindicated in patients with end-stage renal disease (ESRD) or those on dialysis, and dose adjustments are needed for other levels of kidney impairment.
Avoid Driving and Machinery: Due to the risk of drowsiness, avoid performing hazardous activities until you know how the medication affects you.
Disclose Supplements and Herbs: Inform your doctor about all supplements and herbs, such as melatonin or valerian, which could also increase drowsiness.
Monitor for Urinary Retention: Use with caution if you have conditions predisposing you to urinary retention, like an enlarged prostate.

Levocetirizine, commonly known by the brand name Xyzal®, is a second-generation antihistamine used to relieve symptoms of seasonal and chronic allergies, such as sneezing, runny nose, and hives. While it is generally well-tolerated and considered less sedating than first-generation antihistamines like Benadryl (diphenhydramine), it can still cause drowsiness and fatigue. This is why knowing what drugs should not be taken with levocetirizine is vital for patient safety, as many common substances can significantly increase the risk of adverse effects.

The Primary Concern: Central Nervous System (CNS) Depressants

The most significant and potentially dangerous interactions involve substances that act as Central Nervous System (CNS) depressants. These substances slow down brain activity, and when combined with levocetirizine, the sedative and intoxicating effects can be dangerously amplified. This can lead to impaired judgment, coordination, and mental alertness.

Alcohol

Consuming alcohol while taking levocetirizine is strongly discouraged. The combination can lead to excessive drowsiness, dizziness, and difficulty concentrating. Since both are CNS depressants, their effects are additive, increasing the risk of accidents while driving or operating machinery.

Sedatives and Hypnotics

Medications prescribed for insomnia or anxiety, such as benzodiazepines (e.g., alprazolam, clonazepam, lorazepam) and other sleep aids (e.g., eszopiclone, zolpidem), can cause dangerous additive sedation when combined with levocetirizine. This combination can increase the risk of respiratory depression and prolonged impairment of mental and motor skills.

Opioid Pain Relievers

Prescription pain medications like fentanyl and tramadol are powerful CNS depressants. Combining them with levocetirizine can intensify sedative effects, increase the risk of life-threatening respiratory depression, and severely impair coordination.

Certain Antidepressants and Antipsychotics

Some antidepressants, particularly older tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs), can interact with antihistamines. The combination can result in increased sedation and other anticholinergic side effects. Certain atypical antipsychotics, such as aripiprazole, also carry an increased risk of side effects when taken with levocetirizine.

Other Antihistamines

Taking multiple antihistamines concurrently, even if one is a first-generation type like diphenhydramine (Benadryl), should be avoided unless directed by a doctor. Doing so increases the risk of excessive sedation and other side effects. Also, using a nasal antihistamine like olopatadine with levocetirizine can increase CNS depression.

Specific Drug and Condition Interactions

In addition to general CNS depressants, there are specific drugs and health conditions that require careful management or complete avoidance of levocetirizine.

Ritonavir

This medication, used to treat HIV and Hepatitis C, can increase the concentration of levocetirizine in the body by decreasing its metabolism. This heightens the risk and severity of levocetirizine's side effects.

Theophylline

Used for asthma and other breathing problems, theophylline can interact with levocetirizine. While the interaction is typically mild, it can affect the clearance of levocetirizine from the body, potentially requiring dose adjustments.

MAOIs

Monoamine Oxidase Inhibitors (MAOIs) like isocarboxazid and tranylcypromine have a severe interaction risk with levocetirizine due to additive CNS depressant and anticholinergic effects. This combination should be avoided completely.

Other Considerations

Kidney Disease: Levocetirizine is primarily eliminated by the kidneys. Patients with end-stage renal disease (ESRD) or on dialysis should not take it. Children (6 months to 11 years) with renal impairment are also contraindicated. For others with kidney impairment, dosage adjustments are often necessary, and self-medicating with OTC levocetirizine is not recommended.
Urinary Retention: Patients with conditions that predispose them to urinary retention, such as an enlarged prostate (prostatic hyperplasia), should use levocetirizine with caution.

Comparison of Common Interactions


Drug Type	Reason for Interaction	Potential Risk
Alcohol	Additive CNS depressant effect	Excessive drowsiness, impaired judgment, poor coordination
Benzodiazepines (e.g., Xanax)	Additive CNS depressant effect	Increased sedation, respiratory depression, impaired mental alertness
Opioids (e.g., Fentanyl, Tramadol)	Additive CNS depressant effect	Increased sedation, respiratory depression, severe impairment
Other Antihistamines	Additive CNS depression	Increased risk of side effects like drowsiness and dry mouth
Ritonavir	Decreased metabolism of levocetirizine	Increased levocetirizine blood levels and side effects

Practicing Safe Medication Use

To ensure your safety while taking levocetirizine, it is essential to be proactive and informed. Always read the product label carefully and follow the dosing instructions. Never exceed the recommended dose, as this increases the risk of side effects like excessive drowsiness. Inform your doctor or pharmacist about all other medications, over-the-counter drugs, herbal products, and supplements you are taking. This is particularly important for substances that can also cause sleepiness, such as melatonin or cannabis. Until you understand how levocetirizine affects you, it is best to avoid activities that require complete mental alertness and motor coordination, such as driving or operating heavy machinery. In case of overdose or suspected severe interaction, seek immediate medical attention or contact a poison control center. A good resource for comprehensive drug information is the U.S. National Library of Medicine's MedlinePlus drug information page for Levocetirizine.

Conclusion

While levocetirizine is an effective and widely used antihistamine, its safety profile relies heavily on avoiding certain drug and substance interactions. The most important rule is to steer clear of alcohol and other CNS depressants, which can dangerously amplify sedative effects. Additionally, caution is needed with specific prescription medications like Ritonavir and Theophylline, and certain health conditions like kidney disease. Always consult with a healthcare professional to ensure your medication regimen is safe and to get guidance on any specific concerns. Being aware of these interactions is the best way to manage allergy symptoms effectively while minimizing health risks.

Frequently Asked Questions

No, you should avoid drinking alcohol while taking levocetirizine. Alcohol is a CNS depressant, and when combined with levocetirizine, it can cause excessive drowsiness, dizziness, and severely impaired judgment.

It is generally not recommended to combine levocetirizine with other oral antihistamines, especially sedating first-generation types, as this can lead to excessive drowsiness and other side effects. Always consult your doctor or pharmacist before combining allergy medications.

Combining levocetirizine with sleeping pills, which are CNS depressants, can significantly increase the risk of severe drowsiness, respiratory depression, and impaired mental and physical function. This combination should be avoided.

Patients with end-stage renal disease or those on dialysis should not take levocetirizine. If you have any degree of kidney impairment, your doctor will need to adjust your dosage. Never take over-the-counter levocetirizine if you have kidney problems without medical advice.

Yes, some antidepressants, particularly older types like MAOIs, can have serious interactions with antihistamines, increasing sedative and anticholinergic effects. If you are on an antidepressant, discuss this with your doctor before starting levocetirizine.

Unlike some other antihistamines like fexofenadine, levocetirizine is not known to interact with foods or non-alcoholic drinks. However, always discuss any food concerns with your doctor.

Yes, because levocetirizine can cause drowsiness, fatigue, and impaired coordination, you should avoid driving or operating machinery until you know how the medication affects you.