Taking Nyquil With Mucinex
In our latest question and answer, the pharmacist discusses whether or not it is safe to take Nyquil with Mucinex.

Question
Hello, I have a terrible cold and want to know if you can take Mucinex with Nyquil?

Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist
Staff
Last updated Mar 26, 2025
Key points
- There is no known drug interaction between NyQuil and Mucinex (guaifenesin). They are safe to take together.
Hello and thanks for your question!
The answer to this one is straightforward, Mucinex (guaifenesin) can be safely taken with Nyquil. There is no listed or reported interaction between the two drugs.
In the next sections, I discuss both in a little more detail.
Mucinex Information
Mucinex (guaifenesin) is an expectorant that thins and loosens mucus (i.e. phlegm) in the throat and chest area.
As a result, bronchial secretions/fluids are less viscous (i.e. thick) and are less likely to stick in the airways. This allows you to more easily expectorate the mucus.
Based on the expectorant actions of Mucinex, it can be beneficial for reducing cough associated with postnasal drip.
Mucinex is typically very well tolerated and has minimal side effects.
Branded Mucinex products (i.e. Mucinex 12 Hour) are 'dual-layer' tablets. One part of the tablet dissolves quickly, for a fast effect, while the other layer dissolves slowly, to allow for an extended-release effect.
Mucinex begins to work in about 20 to 30 minutes after taking a dose and lasts about 12 hours.
There are 'immediate-release' products on the market as well, and these last about 4-6 hours per dose.
Mucinex is a very common ingredient in combination cough/cold products, so it is important to be prudent and look at the 'drug facts' label on each product you are using to avoid doubling up on the medication.
Nyquil Information
Nyquil is a family of products that contain a variety of medications indicated for the treatment of cold/flu symptoms. Nyquil products also contain doxylamine, a sedating antihistamine.
There are a variety of Nyquil products available on the market in the United States, including:
- Nyquil
- Nyquil Cough
- Nyquil Sinus
- Nyquil D
- NyQuil Severe
Nyquil, the original and most commonly used product, contains the following ingredients:
- Acetaminophen (analgesic)
- Dextromethorphan (cough suppressant)
- Doxylamine (sedating antihistamine)
The other Nyquil products contain similar ingredients, with the main difference being whether or not they include a decongestant (e.g. phenylephrine, pseudoephedrine). None of the Nyquil products contain guaifenesin so there is no issue with taking too much of that ingredient when combining Nyquil and Mucinex.
Final Words
As mentioned above, there is no interaction between Mucinex and any of the Nyquil products. They may be safely taken together.In fact, many of the ingredients found in Nyquil are often included in other combination cough/cold products that also contain guaifenesin.
Thanks again for your question!
References
- NyQuil Manufacturer Website, Vicks.com
- Mucinex Manufacturer Website, Mucinex.com
- Guaifenesin Monograph, PubChem
- NyQuil Monograph, ClinicalKey (Subscription Needed)
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Dr. Brian Staiger, PharmD
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