Mucinex and NyQuil are two common over-the-counter remedies for cold and flu symptoms. It is generally safe to take them together, but not at night. Mucinex can cause coughing, making it hard to get a good night’s sleep.

Mucinex and NyQuil are both products that relieve symptoms of the common cold or flu. However, the symptoms they treat are different.

They can be taken together safely if you follow the recommended dosage for each drug. However, taking Mucinex at night with NyQuil might actually keep you from falling asleep. Mucinex will loosen your mucus, which can cause you to wake up in order to cough.

When deciding between the two, it can be helpful to consider the symptoms that each drug treats, as well as their side effects and interactions, to understand what may be best for you.

The main differences between these drugs are their active ingredients and how those work to treat your symptoms.

Mucinex treats chest congestion. The main active ingredient is an expectorant called guaifenesin. It works by thinning the consistency of mucus in your air passages, loosening it up so you can cough it up and out.

NyQuil temporarily treats several cold and flu symptoms, such as:

The active ingredients are acetaminophen, dextromethorphan, and doxylamine. These ingredients each work a little differently:

  • Acetaminophen. This is a pain reliever and fever reducer that changes the way your body senses pain and regulates temperature.
  • Dextromethorphan. This drug suppresses the signals in your brain that trigger your coughing reflex.
  • Doxylamine. This drug blocks a substance in your body called histamine. This substance causes allergy symptoms such as itchy, watery eyes, runny nose, and itchy nose or throat.

Together, these ingredients provide the relief you can get from NyQuil.

The following table summarizes the differences between Mucinex and NyQuil at a glance.

DifferenceMucinexNyquil
Active ingredient(s)guaifenesinacetaminophen, dextromethorphan, doxylamine
Symptom(s) treatedchest congestionfever, cough, nasal congestion, minor aches and pains, headache, sore throat, runny nose, sneezing
Usagethroughout the dayat night
Formsextended-release oral tablet*, oral granulesoral liquid capsule, oral solution
Risk of interactionsnoyes
Risk of serious side effectsnoyes

*There is also an extra-strength form of this tablet, which contains twice as much of the active ingredient.

Forms and dosage

You can use Mucinex throughout the day, but you typically use NyQuil at night to help you sleep and let your body recover. The ingredient doxylamine in NyQuil also causes drowsiness to help you get rest.

Mucinex and NyQuil are only for people 12 years and older. However, NyQuil has other products especially made for children ages 4 to 11.

The American Academy of Pediatrics (AAP) recommended avoiding giving cough and cold medications to children younger than six years. This is because it can lead to increased risk of side effects and may also have limited effectiveness.

The recommended dosage for each drug varies according to the form. Follow the recommended dosage on the package of whatever form you choose. It’s important to speak with a healthcare professional, such as a pharmacist, for the correct dosage of NyQuil to give to children who are 4 to 11 years old.

Side effects

Mucinex and NyQuil may each cause some side effects. The following table compares them. A pharmacist may be able to recommend a remedy to prevent or ease mild side effects. For example, try taking these drugs with food if they cause stomach pain, nausea, or vomiting.

Common side effectsMucinexNyQuil
headacheXX
nauseaXX
vomitingXX
dizzinessX
lightheadednessX
stomach painX
dry mouthX
drowsinessX
restlessnessX
nervousnessX

Mucinex does not have the risk of serious side effects. However, the following serious side effects may be possible with NyQuil:

  • vision problems, such as blurry vision
  • difficulty urinating
  • allergic reaction, with symptoms such as:
    • red, peeling or blistering skin
    • rash
    • hives
    • itching
    • swelling of the face, throat, tongue, lips, eyes, hands, or lower legs
    • difficulty breathing or swallowing

If you have serious side effects, you should stop using the drug and seem medical support immediately

Interactions

Drug interactions can increase or decrease the effect of the other medications. Interactions can also increase your risk of side effects. There are no known significant interactions with guaifenesin, the active ingredient in Mucinex. However, all three active ingredients of NyQuil interact with other drugs.

If you are taking prescription medications, especially any that may cause drowsiness, it can be helpful to speak with a healthcare professional before taking NyQuil.

You shouldn’t use Mucinex or NyQuil to treat a long-term cough. Using too much can cause harmful effects. You also shouldn’t use these products to treat symptoms of any medical condition you have without talking with a doctor first.

Other conditions

Other conditions you may have can affect how NyQuil works for you. In some conditions, this drug can be harmful. Speak with a healthcare professional before using NyQuil if you have:

  • liver disease
  • glaucoma
  • problems urinating due to enlarged prostate gland

Overuse

You shouldn’t use Mucinex or NyQuil for longer than seven days. If your symptoms aren’t relieved after a week, you should stop taking these drugs and speak with a doctor

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Mucinex and NyQuil are both products that relieve symptoms of the common cold or flu. The symptoms they treat are different. You can take Mucinex and NyQuil together safely if you follow the recommended dosage for each drug. However, taking Mucinex at night with NyQuil might actually keep you from falling asleep. Mucinex will loosen your mucus, which can cause you to wake up to cough.

Deciding between the two may simply mean choosing the drug that treats the symptoms that are bothering you the most. Of course, you should never take any drug if you’re not sure how to use it or if it’s right for you. Always talk with a if you have questions.