Can You Mix Mucinex With Cough Syrup?

It depends on the cough syrup in question.


I was wondering if it was safe to mix two over the counter medications, Mucinex and cough syrup?

Asked by Micky On Dec 29, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Dec 29, 2018
Red Cough Syrup Being Poured


It depends on what the active ingredient in the cough syrup is. 'Cough syrup' is bit of a generic term, so it is important to figure out what the 'cough syrup' actually contains.

Mucinex (guaifenesin) is actually in active ingredient in many over the counter (OTC) cough syrups so the most important consideration is to not take a cough syrup that already contains guaifenesin. Doing so could result in an increased risk of side effects from too high of a dose.

The most common ingredient in cough syrups, aside from guaifenesin, is dextromethorphan. Dextromethorphan is safe to take with guaifenesin. In fact, many cough products contain both, such as Mucinex DM and Robitussin DM.

In terms of actual drug interactions, Mucinex (guaifenesin) is one of the few drugs that isn't known to have any clinically significant ones. So, as long as the 'cough syrup' you are looking at doesn't contain guaifenesin, Mucinex will be safe to take with it.

In the next section, let's look at some popular over the counter cough syrups so you can get an idea of their contents.

  • Delsym
  • Robitussin products
  • DayQuil

Answer Summary

As long as the cough syrup doesn't already contain guaifenesin as an active ingredients, it is safe to take with cough syrup products.

Cough Syrups


Delsym is an extended release cough syrup that contains dextromethorphan. As stated above, dextromethorphan is safe with guaifenesin. Therefore, Mucinex is safe to take with Delsym.

Robitussin/Robitussin DM

There are over 7 Robitussin products available, such as Robitussin Cough and Chest and Robitussin Multi-Symptom CF.

Since there are so many different types of Robitussin products, it is extremely important to look at the 'Drug Facts' on the packaging. If the Robitussin product contains guaifenesin, it should not be taken with Mucinex.

If the Robitussin products does not contain guaifenesin (such as Robitussin 12 Hour Cough Relief), then Mucinex will be safe to take with it.


Like Robitussin, there are a variety of DayQuil products available, all with different ingredients.

DayQuil (the non-severe formula) is safe to take with Mucinex since it does not contain guaifenesin.

However, DayQuil Severe, which does contain guaifenesin, should not be taken with Mucinex.

Mucinex Info

Mucinex On Black BackgroundMucinex (guaifenesin) is an expectorant for the treatment of chest congestion. It is commonly used to treat cough due to colds and respiratory infections. It is classified as a mucolytic, since it aids in the breakdown of mucus.

Mechanism Of Action

Guaifenesin works by thinning and loosening mucus/bronchial secretions. Specifically, it reduces the viscosity and adhesiveness of these secretions, making them easier to remove and cough out. This can help to change a dry, unproductive cough to one that is more productive.

Side Effects

Adverse reactions to guaifenesin, when given at recommended dosages, are uncommon and generally not serious. Nevertheless, the following side effects have been reported:

  • Nausea
  • Vomiting
  • Diarrhea
  • Drowsiness
  • Dizziness
  • Headache

Excessive use/high doses of guaifenesin have been reported to cause kidney stones, but this is thought to be extremely rare. In case reports, other factors contributed to their formation as well.

Drug Interactions

There are no known drug interactions with guaifenesin.


(Adults) Immediate Release: 200 to 400 mg every 4 to 6 hours as needed

(Adults) Extended Release: 600 to 1200 mg every 12 hours as needed

(Adults) Maximum Daily Dose: 2400 mg/day

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