Cetirizine

( Zyrtec )

Medically Reviewed by HaVy Ngo, Pharm.D.

Last Reviewed: Jun 14, 2022

Pharmacist Tips


Lisinopril (Prinivil, Zestril) tips from pharmacists

  • Even though cetirizine (Zyrtec) typically does not make you as drowsy as Benadryl (diphenhydramine), in the beginning, you should take cetirizine in the evening when you don’t have to drive or perform activities that require alertness. Once you know how your body reacts to this medication, you can take it at any time of the day; cetirizine works as quickly as 1 hour after taking it. 

  • If you use cetirizine oral solution for you or your child, you should use an oral syringe or liquid medicine cup to ensure the most accurate dosing. Household items like tablespoons do not provide the most precise dosing. You can ask your pharmacist if you don’t have these items. 

  • If you have phenylketonuria (PKU), cetirizine chewable tablets are not the safest choice for you. Some of these chewable tablets contain phenylalanine which can cause serious health problems for people with PKU. However, you can still take the regular tablets, the oral-disintegrating tablets, or the oral solution without a problem.

  • Cetirizine may interfere with certain laboratory tests, such as allergy skin testing. Make sure you inform the doctor and lab personnel if you use cetirizine.