Taking DayQuil With Zyrtec (Cetirizine)

In our latest question and answer, the pharmacist discusses whether or not DayQuil can be taken with Zyrtec (cetirizine).


Can you take DayQuil and Zyrtec together?

Asked by Jimmi On Nov 20, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Nov 20, 2022
Last updated Nov 20, 2022

Key points

  • DayQuil and Zyrtec can be used together. There is no interaction between the two drugs.


Zyrtec (cetirizine) and Dayquil may be safely taken together as there is no drug interaction between the two medications.

It is important to emphasize that it is always a good idea to look at the labels of the over-the-counter cough/cold products you are looking to take as many of them include multiple ingredients.

In general, you don't want to combine two products if they contain the same, or similar, drugs. Fortunately, DayQuil does not contain an antihistamine and is safe to take with Zyrtec (a second-generation antihistamine).

There are some Zyrtec products and some DayQuil products that shouldn't be combined, however.

For example, Zyrtec-D (cetirizine; pseudoephedrine) shouldn't be used with DayQuil as both contain decongestants. We wrote about this in another answer (which can be found here if you're interested).

Taking DayQuil With Zyrtec (Cetirizine)


Dayquil is a combination ingredient cough/cold/flu medication that contains the following ingredients:

  • Acetaminophen (Pain reliever/fever reducer)
  • Dextromethorphan (Cough suppressant)
  • Phenylephrine  (Nasal decongestant)

While DayQuil has a number of ingredients that will help with cold and flu symptoms, it does not contain an antihistamine. Therefore, if you have seasonal allergies, DayQuil will not prevent them from occurring.

In many cases and situations, it is a good idea to combine an antihistamine, such as Zyrtec (cetirizine) with DayQuil to provide all-around symptom relief.

Zyrtec (Cetirizine)

Zyrtec is a "second generation" antihistamine that is an effective all-day (i.e. 24 hour) allergy medication.

Most second-generation antihistamines, such as Claritin and Allegra, do not cause drowsiness or sedation. However,  Zyrtec is not considered non-drowsy. The prescribing information for Zyrtec shows around 13% of users will experience sedation or drowsiness.

Zyrtec is beneficial for preventing allergy symptoms such as:

  • Running nose
  • Congestion
  • Post nasal drip
  • Itchy, watery eyes

Combining The Two

As mentioned, DayQuil and Zyrtec can be taken together and both may be recommended based on your symptoms. It is important to be aware however, the Zyrtec may cause drowsiness in some individuals. If you are looking for a "non-drowsy" antihistamine to take with DayQuil, consider Allegra or Claritin.

Final Words

Thanks for reaching out and please do so again anytime!


  • DayQuil Manufacturer Website, Vicks
  • Cetirizine Monograph, PubChem

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at Hello@HelloPharmacist.com! You can also connect with Dr. Brian Staiger on LinkedIn.

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