Can You Take Zyrtec And Singulair Together?

In our latest question and answer, the pharmacist discusses if Zyrtec and Singulair can safely be used together.


I was told by my doctor to use Zyrtec, and it's been helpful for allergies. I still need some help though and I was reading about Singulair. Is it safe to use that even though I'm already taking an antihistamine?

Asked by Albie On Nov 22, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Nov 22, 2022
Last updated Sep 29, 2023

Key points

  • There is no known drug interaction between Zyrtec and Singulair. They can safely be taken together.
  • Some studies suggest the combination of an antihistamine like Zyrtec and Singulair can be more effective at treating certain allergy symptoms than either drug alone.


Yes, Zyrtec (cetirizine) and Singulair (montelukast) can safely be taken together. There is no drug interaction between them.

Both drugs work via different mechanisms and do not interfere with one another. In fact, several studies show that combining an antihistamine, like Zyrtec, and a leukotriene receptor antagonist (LTRA), like Singulair, can be more effective in treating allergy symptoms than either drug alone (although data is mixed in this regard).

What Do Studies Show?

As mentioned, you may get the most relief of your allergy symptoms if you combine drugs like Zyrtec and Singular.

One study, which evaluated the combination of antihistamines and leukotriene antagonists, concluded the following:

The current evidence suggests that LTRAs [leukotriene receptor antagonists such as Singulair) + H1 [histamine-1 blockers, like Zyrtec] can increase the therapeutic efficacy against daytime and composite nasal symptoms, including rhinorrhea, sneezing, and itching...
Otolaryngol Head Neck Surg . 2018 Mar;158(3):450-458.

Other studies have found somewhat conflicting results, but there is no interaction between the drugs, and they, at the very least, won't alter how the other works.

Zyrtec And Singular Work In Different Ways

Zyrtec and Singulair work via different pathways to help treat allergy symptoms.

Zyrtec is a second-generation antihistamine, which blocks the H1 (histamine-1) receptor, preventing histamine from binding to it (which prevents the histamine-induced inflammatory response).

Singulair blocks the leukotriene D4 (LTD4) receptor. This, in turn, blocks the action of several different substances in the body that cause allergy symptoms.

Although Zyrtec and Singulair prevent the release of similar substances (e.g., mast cells, eosinophils), they do so differently.

Final Words

I hope you found this helpful!

I also hope you find your new therapy of Zyrtec and Singulair effective. I know how challenging it can be to find effective therapies to treat allergies.

Thanks for reaching out!


  • Pharmacotherapy for allergic rhinitis: a critical review of leukotriene receptor antagonists compared with other treatments, Science Direct
  • Oral Antihistamines Alone vs in Combination with Leukotriene Receptor Antagonists for Allergic Rhinitis: A Meta-analysis, PubMed
  • Role of leukotriene antagonists and antihistamines in the treatment of allergic rhinitis, PubMed
  • Management of allergic rhinitis with leukotriene receptor antagonists versus selective H1-antihistamines: a meta-analysis of current evidence, Allergy, Asthma & Clinical Immunology

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! You can also connect with Dr. Brian Staiger on LinkedIn.

Recent Questions