Taking Benadryl With Claritin

We often get asked if it is OK to take a certain combination of drugs together. It is always a good idea to double check into this situation if you are unsure if they are compatible. In our latest question and answer, we explore taking the combination of Benadryl and Claritin.

Question

Can I take Benadryl (Diphenhydramine) and Claritin (Loratadine) together?​​ I want I have bad allergies and need more relief.

Asked by Arlene On Oct 22, 2017

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Oct 22, 2017
Benadryl Claritin Bottles

Overview

In most cases, it is not recommended to take Benadryl and Claritin together...but there are some exceptions which we discuss below.[1]

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 when 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.[2]

Section Summary

Benadryl and Claritin are antihistamines and have the same mechanism of action. Benadryl causes significantly more sedation and only lasts four to six hours while Claritin is non-sedating and lasts 24 hours per dose.

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 their own does a pretty good 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 the sedative effects of the drug.

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.

Section Summary

Your doctor may recommend to take Claritin and Benadryl together in certain situations, such as if you are having an allergic reaction.

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.
References
  1. ^ Elsevier ClinicalKey Drug Interaction Report. ClinicalKey (Subscription Required)
  2. ^ H1 Antihistamines: Current Status and Future Directions. PubMed
  3. ^ Diphenhydramine versus nonsedating antihistamines for acute allergic reactions: a literature review. PubMed

About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of PharmacistAnswers.com. He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Brian.Staiger@PharmacistAnswers.com Office: 716-389-3076

About Claritin (Loratadine)

Claritin (loratadine) is an non-sedating, "second-generation" antihistamine (H1-blocker). Unlike "first-generation" antihistamines, Claritin doesn't penetrate the central nervous system in high concentrations an therefore, does not cause significant sedation. Claritin was first approved by the FDA in April 1993 as a prescription medication and was approved for over the counter sale in December 2002. Claritin may be taken with or without food, with the onset of action occurring within 1 to 3 hours. Peak effects are generally seen in 8 to 12 hours. Claritin has a long duration of action and is therefore dosed once daily.

About Benadryl (Diphenhydramine)

Benadryl (diphenhydramine) is a first generation, sedating antihistamine (H1-blocker) of the ethanolamine class. It is available in oral, topical, and parenteral product forms. Benadryl is well known to cause significant sedation in most individuals and is commonly used in night-time sleep aids. Benadryl also has potent "drying" effects in most patients, which is why is causes dry mouth, dry eyes and constipation. The onset of action of Benadryl is around 15-30 minutes after taking by mouth, with peak effects occurring 1 to 3 hours later. The duration of action is around 4 to 6 hours, with this being prolonged in the elderly and in those with liver disease.

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