How Often Can You Give Benadryl To Treat An Allergy?

In our latest question and answer, the pharmacist discusses how often Benadryl can be taken for allergies.

Question

My husband broke out in hives all over his back and stomach, after pulling some honeysuckle vines off of s fence. We gave him 50 mg of Benadryl. How often can we do this, until it goes away? He is breathing fine.

Asked by Freda On Mar 23, 2019

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Mar 24, 2019
How Often Can You Take Benadryl For Hives Text Over Image Of Man Scratching leg

Benadryl (diphenhydramine) is recommended to be taken every four to six hours as needed, regardless of what you are using it for (e.g. allergic reaction, runny nose etc...).[1]

In your situation, with your husband suffering from hives due to an allergy to honeysuckle, Benadryl is a good option to take to help stem the symptoms of his reaction.

The recommended dose to treat hives (also known as urticaria) for adults is 25-50 mg (one to two tablets) by mouth every four to six hours.

Benadryl For Hives

Antihistamines, like Benadryl, are generally recommended as a 'first-line' therapy for the treatment of hives.

Treatment guidelines for hives published in the journal American Family Physician, state the following:[2]

"When avoidance [of triggers for hives] is impossible, no trigger is identified, or symptomatic relief is still required despite avoidance, antihistamine medications are first-line pharmacotherapy. A variety of additional medications can be used when first-line antihistamines are not adequate."

It is important to note that most studies recommend the use of second-generation antihistamines over first-generation antihistamines (Benadryl is a first-generation antihistamine).

This recommendation is in place because second-generation antihistamines are longer lasting and cause significantly fewer side effects than first-generation ones, like sedation and dry mouth.

Over the counter, second-generation antihistamines include:

  • Allegra (fexofenadine)
  • Claritin (loratadine)
  • Zyrtec (cetirizine)

While second-generation antihistamines may be preferred over first-generation ones in most situations, the first-generation antihistamines likely work faster.

The same guidelines referred to above state the following regarding first-generation antihistamines:

"With more severe symptoms, first-generation H1 blockers may be used for their more rapid onset of action or parenteral forms. Psychomotor adverse effects should be discussed with patients before initiation of therapy."

Additionally, other studies, such as one titled 'Challenges in the Management of Chronic Urticaria', published in World Allergy Organization Journal, suggests that first-generation antihistamines, like Benadryl, may offer more benefit than second-generation ones since they also have antimuscarinic, anti-α-adrenergic and anti-serotonin effects.[3] These effects all help to reduce the itching and swelling of hives.

As stated above, the recommended dose of Benadryl for the treatment of hives in adults is 25 to 50 mg every four to six hours. Based on those directions, you could take a dose up to 6 times per day.

Additional Information

Benadryl can be taken until your symptoms have resolved.

However, since it can be quite sedating, you may want to switch to a non-sedating antihistamine, like Claritin or Allegra, for long-term use.

Answer Summary

Benadryl (diphenhydramine) can be used to treat urticaria (hives). You can take a dose (25 to 50 mg) every four to six hours.

References
  1. ^ Elsevier ClinicalKey: Diphenhydramine Monograph
  2. ^ Urticaria: Evaluation and Treatment. American Family Physician
  3. ^ Challenges in the Management of Chronic Urticaria. 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

Recent Questions