Concerns Combining Xanax And NyQuil

In our latest question and answer, our pharmacist discusses concerns with combining Xanax and NyQuil.


I have been taking 1.5 mg of Xanax every night for sleep for the past 10+ years. I have a cold and was wondering if it is okay to take NyQuil. I took my Xanax at 9:30 PM and it is now 11:35 PM. Is this okay?

Asked by Patti On Feb 02, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Feb 03, 2023
Last updated Feb 03, 2023

Key points

  • Combining NyQuil and Xanax can increase the risk of side effects such as sedation, confusion, drowsiness, respiratory depression, and weakness as NyQuil contains the sedating antihistamine doxylamine, which enhances the CNS (central nervous system) depressant effects of Xanax.
  • It is recommended to avoid combining the two medications or to separate their doses by at least four to six hours if they must be used together.


Thanks for reaching out to us!

We have actually answered this exact question before, and that answer can be found on our website.

To summarize the concerns with combining NyQuil and Xanax:

  • NyQuil contains doxylamine, a sedating antihistamine
  • Xanax (alprazolam) is a benzodiazepine and acts as a CNS (central nervous system) depressant
  • Doxylamine (the antihistamine in NyQuil) may enhance the CNS depressant effects of other CNS Depressants, like Xanax
  • This can increase the risk of side effects, such as sedation, confusion, drowsiness, respiratory depression, and weakness

How To Manage The Interaction

As a general rule of thumb, you don't want to combine drugs like Xanax with other CNS depressants, like NyQuil due to the increased risk of side effects.

Nevertheless, they are sometimes combined if you and your doctor decide it represents the best therapy for you. Just be sure to start at a low dose of each and monitor yourself for side effects.

If you want to avoid the interaction, you should separate the dosing of each by at least four to six hours. Both NyQuil and Xanax have a duration of action around that amount of time, although this can vary by individual.

Final Words

In your question, you mentioned taking Xanax at 9:30 PM and are considering NyQuil at 11:30 PM. In this situation, it's likely that Xanax is still in your system and having an effect on you. As mentioned, I would recommend at least 4 hours between doses to lessen the effects of combined use.

You also have the option of taking other cough/cold medications that don't contain a sedating antihistamine, like DayQuil.

Thanks for reaching out to us! Let us know if we can be of any more help!


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.

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