Taking Benadryl With Claritin

In most cases, it is not recommended to take Benadryl and Claritin together...but there are some exceptions which we discuss below.

How Benadryl And Claritin Work

Both Benadryl and Claritin are antihistamine medications and work the same way mechanistically in the body.

They both work by blocking what is known as the histamine-1 receptor. This prevents histamine from binding to it and producing the allergy symptoms we are all very familiar with (runny nose, stuffy nose, post-nasal drip, etc...).

While they both work the same way, they do have different characteristics. Benadryl is a "first-generation" antihistamine while Claritin is a "second-generation" antihistamine.

First-generation antihistamines are known for their sedative effects and short duration of action. On the other hand, second-generation antihistamines generally last 24 hours per dose and are non-sedating.

Don't Take Together?

Due to the duplicative and additive nature of Claritin (loratadine) and Benadryl (diphenhydramine), the use of both together is not recommended.

Benadryl (diphenhydramine) by itself causes pronounced sedation and this sedation can be somewhat enhanced when combined with Claritin (loratadine), although Claritin is considered essentially non-drowsy.

Other additive side effects that are possible include:

• Dry mouth
• Dry eyes
• Constipation
• Urinary retention

When To Combine

Having said all of the above, there are cases when both are used together.

The interaction we are worried about is the additive drowsiness when both are taken together. Although as mentioned above, Claritin (loratadine) is non-drowsy, combining it with another antihistamine that works the same way could perhaps cause an additive effect of the two.

In addition, you probably would not get any additional benefit from taking Benadryl and Claritin together.

Each drug on its own does a pretty good job of blocking the histamine receptor and taking the two at once would not produce any appreciable difference from just taking one.

We are not really worried about both drugs mixing in the body and causing serious side effects.

One situation where it may be okay to take both close to each other is if you are having an allergic reaction.

It is thought (and multiple studies have reported) that Benadryl is slightly more effective at stemming an allergic reaction (such as to a bee sting) than second-generation antihistamines like Claritin.^[3]

If you take Claritin (loratadine) on a daily basis for your seasonal allergies and were in a situation where you were having a serious allergic reaction, Benadryl (diphenhydramine) may be an appropriate choice to add on before you make it to the hospital.

In a case like this, I would say it would be OK to take both close together and your doctor may recommend it for you.

Lastly, Benadryl is often used as a sleep aid due to its sedative effects.

Your doctor may recommend intermittent use of the drug to help you sleep, only on a short-term, "as needed" basis even when using Claritin daily for allergy prevention.

Summary

• Taking both Claritin and Benadryl together increases the risk of side effects. You also will not experience better allergy relief when taking both together in most cases.

• However, studies indicate that Benadryl may be more effective to treat an allergic reaction, and may be safe and beneficial to take if you are experiencing one, even if you are already taking Claritin.

• Benadryl is sometimes recommended as a sleep aid to be used intermittently, even if you already take a daily antihistamine like Claritin.