Can You Take Benadryl With Delsym?
In our latest question and answer, the pharmacist discusses the use of Benadryl and Delsym together.
Question
Can I give my 6 year-old Benadryl and Delsym in the same hour?

Answered by Dr. Brian Staiger Pharm.D
Medical Content Reviewed By PharmacistAnswers
Staff
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 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.
References
- Elsevier ClinicalKey: Dextromethorphan (subscription required) (Accessed 1/29/19)
- Elsevier ClinicalKey: Diphenhydramine (subscription required) (Accessed 1/29/19)
- Dr. Brian Staiger Pharm.D
- Interaction
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