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

Question
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?

Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist
Staff
Last updated May 11, 2025
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.
Answer
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!
-
Dr. Brian Staiger, PharmD
- 1444 views