How Long After Xyzal Can I Take Benadryl (And Why)?

Exact Answer: 24 Hours

Both of the drugs, i.e., Xyzal and Benadryl are used to treat a person showing symptoms of any kind of allergy. Xyzal and Benadryl are the brand names for the drugs Levocetirizine and Diphenhydramine, respectively. The difference between both medicines is that Xyzal is the second generation of antihistamine, while Benadryl is a first-generation antihistamine. That is why the side effect of sedation is higher in Benadryl as compared with Xyzal. But taking Xyzal also causes some drowsiness. Both of these antihistamines are taken orally, with or without food. But can you take both of these medications? If yes, then how long after taking Xyzal can you take Benadryl?

How Long After Xyzal Can I Take Benadryl

How Long After Xyzal Can I Take Benadryl?

MedicationEffects Last for
Xyzal24 Hours
Benadryl4 – 6 Hours

Xyzal (also known as levocetirizine) is prescribed to treat allergy symptoms of sneezing, watery or itching eyes, and nose. Xyzal is sold either as tablets or in liquid form and the dosage of this medication depends upon the individual’s age and medical condition. Most of the time you are told to consume this medication only once a day. A common side effect of taking Xyzal which you will experience is drowsiness.

On the other hand, Benadryl (diphenhydramine) is known for treating symptoms of hay fever (allergic rhinitis), and cold. Benadryl is also sold as tablets or in liquid form. For this medication, you will be told to consume it 30 minutes before bedtime, or in the case where you will be traveling, 30 minutes before your travel. This is because consuming Benadryl puts you under heavy sedation.

When you take Xyzal, its effect lasts for about 24 hours, and in the case of Benadryl, the effects last for almost 4 to 6 hours. But doctors never prescribe both of these medications, as you must never consume both of these medications at the same time. Consuming both of these medications at the same time might expose you to various side effects. Yet, if you wish to consume both of these medications, you should only consume them when one of the medications’ effects wears off. If you are taking Xyzal first and then Benadryl, you must wait for the effects of Xyzal to wear off. As the effects of Xyzal last for 24 hours, you can only consume Benadryl 24 hours after taking Xyzal.

Why Can I Take Benadryl That Long After Xyzal?

In most cases, a 5mg tablet of Xyzal is prescribed, and when the symptoms are minor, a 2.5mg tablet also works. When you consume Xyzal, you will start experiencing its effects within 1 hour. Some side effects which you are likely to face include drowsiness and tiredness. In the case of children, fever and cough might also occur.

When Benadryl is prescribed to you, usually the dosage is between 25mg – 50mg, depending on the severity of the symptoms. It takes at most 20 – 30minutes for Benadryl to start working. Heavy sedation is one of the main side effects of Benadryl. Other side effects of Benadryl include dizziness, constipation, and impaired vision.

After an allergic reaction happens, your body starts developing a natural substance called histamine. The antihistamines Xyzal and Benadryl work in stopping these substances and giving you relief. But even though it gives you relief from these symptoms, both of them are not made to treat or prevent you from serious allergic reactions like anaphylaxis.

Thus, as both of these medications are prescribed for treating similar symptoms, it is not recommended to take both of them at the same time. As mentioned before, you must wait till one of the medications’ effects wears off, and then only you can take the other. This is because of the side effects these medications show. When you consume both of them together, there is a risk of you experiencing additive antihistamine side-effects, which include dry mouth and eyes, extreme drowsiness, and constipation. Therefore, if you are taking Xyzal first, you must wait for 24 hours, and then consume Benadryl.


Consuming Xyzal and Benadryl at the same time is rarely prescribed as they don’t give you any additional benefit. But when you’re taking both of them, it is quite necessary to take precautions and avoid the additive antihistamine effects. Earlier it was mentioned that you should take Benadryl only when the effects of Xyzal wear off. But when you are taking Benadryl first, there also you must wait for its effects to wear off ( i.e., 4 – 6 hours). However, as the effects of Benadryl take less time to wear off when compared to Xyzal, it is recommended to take Benadryl first. 


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