Benadryl (Diphenhydramine) With Sudafed (Pseudoephedrine) Interaction
In our latest question and answer, the pharmacist discusses whether or not there is an interaction between Benadryl and Sudafed.
Is it OK to take Benadryl and pseudoephedrine together? (I’m also on 20mg prednisone 2 x daily and Mucinex)
Aug 16, 2022- Benadryl and Sudafed are safe to take together with no drug interaction between them.
- Benadryl only lasts 4 to 6 hours, so longer-acting antihistamine-decongestant combinations like Claritin-D, Zyrtec-D, or Allegra-D may be more convenient for daily allergy treatment.
- Taking Sudafed with prednisone may have an additive stimulating effect that could cause insomnia if taken close to bedtime.
Answer
There is no drug interaction between Benadryl (diphenhydramine) and Sudafed (pseudoephedrine). They are safe to take together. In fact, the use of an antihistamine (like Benadryl) and a decongestant (like Sudafed) is a very common, and safe, combination.
Other antihistamine-decongestant combinations include:
- Claritin-D (loratadine with pseudoephedrine)
- Zyrtec-D (cetirizine with pseudoephedrine)
- Allegra-D (fexofenadine with pseudoephedrine)
I do want to mention here that while Benadryl is a good option to help with allergies, it has a very short duration of action (around 4 to 6 hours). If you are looking to treat seasonal allergies that happen to you on a daily basis, one of the above options may be more convenient as they last 24 hours per dose.
Additional Information
Benadryl and Sudafed are also safe to take with Mucinex and prednisone. The only potential issue is that prednisone can be stimulating in certain individuals. Sudafed can do the same. This additive effect will likely be mild if it happens at all but can certainly cause insomnia if taken too close to bedtime.
Glossary — Terms in This Answer
- Drug interaction
- A reaction that occurs when two medicines affect each other's effectiveness or safety when taken together.
- Antihistamine
- A medication that blocks histamine to relieve allergy symptoms like itching and sneezing.
- Decongestant
- A medication that reduces nasal congestion and stuffiness by shrinking swollen nasal tissues.
- Duration of action
- The length of time a medication remains effective in your body.
- Seasonal allergies
- Allergic reactions that occur during specific times of the year when certain plants or trees release pollen.
- Prednisone
- A steroid medication that reduces inflammation and suppresses immune system activity.
- Additive effect
- When two substances combine to produce a stronger effect than either would produce alone.
- Insomnia
- Difficulty falling asleep or staying asleep.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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