Can You Take Xyzal After Benadryl?
In our latest question and answer, the pharmacist discusses when Xyzal can safely be taken after Benadryl.
I took 2 Benadryl today at 10 am, would it be safe to take a Xyzal this evening? I'm suffering from a bad case of hay fever. Thank you.
Sep 11, 2022- You can take Xyzal 4 to 6 hours after Benadryl, but you should wait about 24 hours after taking Xyzal before taking Benadryl since Xyzal lasts longer in your system. Taking both antihistamines together or too close together can cause additive side effects like drowsiness, dry mouth, and dry eyes.
Answer
While Benadryl and Xyzal generally should not be taken at the same time, it is safe to take Xyzal around 4 to 6 hours after your last dose of Benadryl, as the effects of the drug will have worn off by then for most individuals. Per your question, if you took Benadryl at 10 AM, it is safe to take Xyzal later that night.
On the other hand, if you take Xyzal first, you should generally wait 24 hours before taking Benadryl to avoid additive side effects such as sedation, dry mouth, and general drowsiness as Xyzal has a duration of action of around 24 hours.
Benadryl (Diphenhydramine) Information
Benadryl, a first-generation antihistamine, has a duration of action of around 4 to 6 hours, although this can be extended in certain individuals such as in the elderly. One of the main side effects of Benadryl is sedation and is commonly added to over-the-counter sleep products such as ZzzQuil.
Xyzal (Levocetirizine) Information
Xyzal, a third-generation antihistamine, has a duration of action of around 24 hours, and is, therefore, able to be dosed just once a day. Although not classified as "non-drowsy", it does have a lower incidence of sedation and drowsiness than first-generation antihistamines such as Benadryl.
Taking Benadryl And Xyzal Together
As mentioned above, it generally isn't recommended to use antihistamines together. There is a risk of additive antihistamine side effects such as:
- Dry mouth
- Dry eyes
- Drowsiness
- Constipation
However, Benadryl only has a duration of action of 4 to 6 hours. If you take Benadryl first, you can safely take Xyzal 4 to 6 hours later. If you take Xyzal first, you should wait around 24 hours before dosing with Benadryl.
One exception to this could potentially be if you need to use Benadryl to stem an allergic reaction. Out of all the antihistamines, many studies show that Benadryl tends to be the most effective for slowing down the allergic reaction to bee stings, poisonous plants, etc. Just be aware of the additive sedative and other side effects if you do take Benadryl within 24 hours of your Xyzal dose.
References & sources
Glossary — Terms in This Answer
- Antihistamine
- A medication that blocks histamine, a chemical in the body that causes allergy symptoms like itching and swelling.
- Duration of action
- The length of time a medication remains active and effective in your body.
- First-generation antihistamine
- An older type of antihistamine that easily crosses into the brain and commonly causes drowsiness as a side effect.
- Third-generation antihistamine
- A newer type of antihistamine designed to be more selective and cause less drowsiness than older versions.
- Sedation
- A state of calm or drowsiness caused by a medication.
- Additive side effects
- Unwanted effects that become stronger or more severe when two medications with similar side effects are taken together.
- Incidence
- How often or frequently something occurs.
- Diphenhydramine
- The active ingredient in Benadryl, a first-generation antihistamine used to treat allergies and sleep problems.
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...
More answers from Brian →