Is It Safe To Take Benadryl And Zyrtec At The Same Time?

In our latest question and answer, the pharmacist discusses the safety of taking Benadryl (diphenhydramine) and Zyrtec (cetirizine) together.

Apr 28, 2018

Jon asked

Please tell me if you can take Benadryl and Zyrtec together?


Taking Zyrtec (cetirizine) and Benadryl (diphenhydramine) together is not recommended due to the risk of increased adverse events.

Both medications are antihistamines, so taking them together greatly increases the risk of side effects such as:

  • Drowsiness
  • Dry mouth
  • Dizziness
  • Constipation
  • Heart palpitations

In addition, taking two antihistamines together generally does not increase effectiveness for treating allergies and therefore there is no benefit with taking Benadryl and Zyrtec at the same time.

One exception is for the treatment of allergic reactions, such as those to bee stings and contact dermatitis. In many cases, Benadryl has been shown to be more effective than other antihistamines in reducing the severity of allergic reactions.


Zyrtec (cetirizine) is a non-sedating antihistamine approved for the treatment of seasonal allergic rhinitis, chronic urticaria (a type of skin rash), as well ocular pruritis (using ophthalmic drop formulation). The oral form of Zyrtec may be taken with or without food and may be taken in the morning or in the evening. Although considered a non-sedating antihistamine Zyrtec may cause drowsiness in a small percentage of individuals who take it.


Benadryl (diphenhydramine) is a sedating antihistamine used most commonly for the treatment of allergic reactions, seasonal allergies, symptoms associated with the common cold and insomnia. Benadryl may be taken without regard to meals and the most commonly reported side effects is drowsiness. Other commonly reported side effects associated with taking Benadryl include but are not limited to dizziness, fatigue and dry mouth.

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