Taking Benadryl And Sudafed Together

In our latest question and answer, the pharmacist discusses whether or not Benadryl (diphenhydramine) can be taken with Sudafed (pseudoephedrine).


I have really bad congestion and am taking Sudafed (pseudoephedrine) which really seems to be helping. I am having trouble sleeping and was wondering if it was safe to take Benadryl too. I am taking Sudafed 12 hour.

Asked by Jerome On Apr 25, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Apr 25, 2022
Last updated Apr 25, 2022

Key points

  • There is no drug interaction between Benadryl and Sudafed. They can be taken together.
  • It is important to know, however, that if you are taking Benadryl to help you sleep, its effects may be lessened with Sudafed as Sudafed has a mild stimulant effect.

Thanks for reaching out!

Sudafed (pseudoephedrine) and Benadryl (diphenhydramine) can be safely taken together as there is no interaction between the two medications. In fact, there are products available over the counter that combine both ingredients to ease administration of both drugs.

However, it is important to be aware that Benadryl and Sudafed can have conflicting effects. Benadryl tends to cause drowsiness, while Sudafed has a mild stimulating effect. You mentioned that you want to take Benadryl to help you sleep (a common use), but you may find it not working as well if combined with Sudafed. Nevertheless, you can safely take them together.

What Is Sudafed?

Sudafed (pseudoephedrine) is a commonly used nasal decongestant that works by producing vasoconstriction in the nasal passages, which shrinks swollen nasal membranes and relieves nasal congestion. Sudafed also acts to increase airflow in the nasal passages and increase drainage of secretions.

Sudafed is typically well tolerated, but some of the more common side effects include increased heart rate and insomnia (trouble sleeping). Sudafed can have a slight stimulating effect in some, making it difficult to fall asleep easily. Studies show that Sudafed causes insomnia in around 4% to 10% of individuals taking the drug.

Sudafed is available in immediate release formulations, which last around four to six hours as well as extended release (e.g. 12 and 24 hour) formulations.

What Is Benadryl?

Benadryl (diphenhydramine) is a first-generation antihistamine, and has a variety of uses. Most commonly, it is used for allergies and as a sleep aid due to its sedative effects.

It is a common addition to nighttime sleep medications as it can decrease sleep latency (i.e. time it takes to fall asleep).

Taking Benadryl & Sudafed Together

There is no interaction between Benadryl and Sudafed and they are safe to take together. You do want to take into consideration however, that they can have opposing effects if you are using Benadryl to help you sleep. The overall sedative effect of Benadryl may be reduced (based on the stimulant effect of Sudafed)

If you are still having trouble sleeping while also needing to take Sudafed for your nasal symptoms, it is typically a  good idea to avoid taking immediate release Sudafed products within 4 to 6 hours of bedtime and extended release Sudafed products up to 12 hours before bedtime.

A potential short-term alternative to Sudafed for nighttime use is to use a nasal decongestant spray instead (although these can only be used for 2-3 days in a row before causing rebound congestion).

Lastly, I do want to mention that there are (or at least were) several over the counter products that contain both ingredients (Benadryl and Sudafed) if you are looking to combine the two medications. However, many were discontinued as result of the stricter laws regarding Sudafed purchases.

Most of the products that originally contained pseudoephedrine now contain Sudafed PE (phenylephrine).  While there still may be Benadryl (diphenhydramine)/Sudafed (pseudoephedrine) combinations available to purchase, it is more common to see Benadryl and Sudafed PE (phenylephrine) combined with one another as these products are available to be placed on store shelves and not behind the pharmacy counter.

Final Words

Thanks again for your question and feel free to reach out again anytime!


  • Non-prescription sympathomimetic agents and hypertension, PubMed
  • Pseudoephedrine Monograph, PubChem
  • Combat Methamphetamine Epidemic Act, DEA

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Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at Hello@HelloPharmacist.com! You can also connect with Dr. Brian Staiger on LinkedIn.

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