Can You Take Benadryl With Delsym?

In our latest question and answer, the pharmacist discusses the use of Benadryl and Delsym together.


Can I give my 6 year-old Benadryl and Delsym in the same hour?

Asked by Katie On Jan 27, 2019

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Jan 30, 2019


Yes, Benadryl (diphenhydramine) may safely be given with Delsym (dextromethorphan), and they very commonly are. There is no known drug interaction between the two medications.

You can feel safe giving both at the same time or at separate times throughout the day. If you are looking for a single product that contains both Benadryl and Delsym, there, unfortunately, aren't any, but there are many with very similar combinations.

What Is In Benadryl?

Benadryl contains diphenhydramine, a sedating, first-generation antihistamine that is used for a variety of purposes, from allergy prevention to use as a sleep-aide.

The use of second-generation antihistamines, like Zyrtec and Claritin, are often more popular choices when it comes to allergy prevention as they are non-drowsy and have a much longer duration of action (around 24 hours versus 4-6 for diphenhydramine).

Nevertheless, diphenhydramine is often preferred for treating allergic reactions, such as hives, and due to the sedative properties, as a sleep-aid. In fact, diphenhydramine is a common ingredient in night-time formulation cough & cold products (e.g., Tylenol PM contains diphenhydramine).

What Is In Delsym?

Delsym contains dextromethorphan, a cough suppressant which helps to treat dry, non-productive coughs. It is available in both immediate and extended-release formulations. Immediate-release products last around 4 to 6 hours per dose, while extended-release formulations last up to 12 hours.

Dextromethorphan is one of the most commonly used ingredients in combination with cough & cold products, including:

  • DayQuil
  • Mucinex DM
  • NyQuil
  • Robitussin DM
  • Tylenol Cold & Flu

Do Benadryl And Delsym Come Together?

Although there is no single product that contains both diphenhydramine and dextromethorphan (excluding 'day + night' combo packs), there are many that are similar.

In combination products, doxylamine is usually the sedating antihistamine you will find. It is very closely related to diphenhydramine in that it is sedating and has a relatively short duration of action, around 4 to 6 hours.

Several over-the-counter products include doxylamine and dextromethorphan, such as Vicks NyQuil

Answer Summary

There is no interaction between Benadryl (diphenhydramine) and Delsym (dextromethorphan). A similar antihistamine, doxylamine, is often found in combination with dextromethorphan.

  • Elsevier ClinicalKey: Dextromethorphan (subscription required) (Accessed 1/29/19)
  • Elsevier ClinicalKey: Diphenhydramine (subscription required) (Accessed 1/29/19)

About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Office: 716-389-3076

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