Is Mucinex The Same As Benadryl?

No, they contain different medications.


Is Mucinex the same as Benadryl? I want to make sure I'm not taking two of the same thing. Thanks!

Asked by Steven On Dec 05, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Dec 05, 2018


Mucinex and Benadryl are not the same as they contain different active ingredients. Mucinex contains guaifenesin, an expectorant, while Benadryl contains diphenhydramine, an antihistamine.

So, not only do Mucinex and Benadryl have different ingredients, they are different classes of medication altogether.

Mucinex (guaifenesin) works by loosening/thinning phlegm and bronchial secretions.

By reducing the thickness and adhesiveness of these secretions, our mucociliary mechanism can more efficiently remove then from the upper and lower airway.

This can help to change a dry, unproductive cough to one that is more productive.

Benadryl (diphenhydramine) is a 'first-generation' antihistamine. It is most often used to treat allergy symptoms (e.g. itching/redness) and insomnia, due to its sedative effects. Additionally, it has a 'drying' effect for most individuals, which can help to clear up chest congestion and bronchial secretions.

Diphenhydramine is actually an active ingredient in many over the counter sleep aid products, such as Tylenol PM and ZzzQuil.

It is important to note that Mucinex and Benadryl can be used together to relieve a variety of cough/cold symptoms. There is no interaction between the two and they are very often used together.

Below is some additional information regarding both drugs.

Guaifenesin Information

Guaifenesin is an expectorant used for dry, un-productive cough when there is the presence mucus in your chest or airways.

It works by thinning and loosening mucus and bronchial secretions. This then promotes ciliary action and changes an unproductive cough to one that is more productive, relieving chest congestion.

Guaifenesin is an ingredient contained in many combination non-prescription (over-the-counter or OTC) cough and cold products including DayQuil and Robitussin DM.

Diphenhydramine Info

Diphenhydramine is a first generation, sedating antihistamine (H1-blocker) of the ethanolamine class. It is available in a variety of different products and dosage forms, including:

  • Oral (tablets, capsules etc...)
  • Topical (creams, gels)
  • Injectable

First-generation antihistamines, especially ones in the 'ethanolamine' class, have significant anticholinergic effects. For this reason, they are effective in treating symptoms of nausea, vomiting and motion sickness but can cause significant sedation (which is why they are commonly used in OTC treatments for sleep).

Being an antihistamine, Benadryl is often used to treat minor allergic reactions, seasonal allergies, and for symptoms associated with the common cold.

However, if an antihistamine is needed on a consistent basis, 'second-generation' antihistamines, such as Claritin or Allegra, may be better options due to the lack of sedative effects and longer duration of action.

Topical formulas are used to relieve pain, redness and itching associated with insect bites, minor burns or cuts, skin irritations or rashes.

The onset of action of oral Benadryl is around 15-30 minutes, with peak effects occurring 1 to 3 hours later. The duration of action is around 4 to 6 hours, with this being prolonged in the elderly and in those with liver disease.

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