Zyrtec Drug Interactions

by on May 3, 2012

Unlike other antihistamines, Zyrtec is not known to cause major drug interactions. However, it is known to mildly interact with certain drugs.

Since Zyrtec is a nonprescription drug and is easily available over the counter, you need to be aware of the drugs that can potentially interact with it. If you are taking it under medical supervision, inform your healthcare provider of all the medications you take and normally take. Do not adjust your dose or stop taking the medication, unless specifically instructed by your healthcare provider.

Usually, drugs that cause drowsiness cause moderate interaction when taken along with Zyrtec. These drugs tend to potentiate the central nervous system (CNS) effects of Zyrtec leading to more severe drowsiness and other CNS symptoms.

Significant Drug Interactions

Some of the drugs that can interact with Zyrtec include:

Medications That Cause Drowsiness – Although second-generation antihistamines, including Zyrtec, are considered non-sedating some people may experience sedation with this drug. Taking Zyrtec along with other drugs that can cause drowsiness increases the risk of serious central nervous system side effects, such as confusion, difficulty breathing, or memory loss. Furthermore, patients who are sensitive to the effects of CNS-active drugs may experience serious reactions.

Discuss with your healthcare provider use of Zyrtec if you are taking any of the following medications that cause drowsiness:

Other antihistamines

  • diphenhydramine (Benadryl)

Anti-seizure medications

  • carbamazepine (Atretiol, Carbatrol, Tegretol)

Medicines for sleep or anxiety

  • alprazolam (Xanax)
  • diazepam (Valium)
  • zolpidem (Ambien)

Muscle relaxants

Narcotic pain relievers

  • codeine

Psychiatric medicines

  • amitriptyline (Vanatrip)
  • chlorpromazine (Thorazine)
  • risperidone (Risperdal)
  • trazodone (Desyrel)

Bronchodilator – Theophylline interferes with the metabolism of cetirizine which can lead to increased blood levels of cetirizine. This can increase the risk of cetirizine side effects. Inform your healthcare provider if you are taking theophylline.

  • Theophylline (Aerolate, Slo-bid, Theo-Dur)

Check the product information label of all medications that you take (such as cough-and-cold products) because they may contain substances that can cause drowsiness. Discuss with your healthcare provider or pharmacist use of these drugs together with Zyrtec.

Lastly, this medication guide may not contain all drugs that can possibly interact with Zyrtec. Therefore, be sure to discuss with your healthcare provider all the medications (both prescription and non-prescription) that you normally take.