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Can Antihistamines Cause Pulmonary Disorders?

Posted on Fri, 17 Mar 2017

Question: My Benadryl bottle says to ask a doctor before use if you have breathing problems such as chronic bronchitis, and my stepfather told me antihistamines worsen his asthma. What is the relationship between antihistamines and pulmonary conditions? I thought antihistamines improve not worsen respiratory functioning.

Answered by Dr. Shoaib Khan (1 hour later)

Brief Answer:
Bronchitis: narrowing of respiratory tract; benadryl: bronchoconstriction

Detailed Answer:
Hello sir and welcome.

Thank you for writing to us.

I have gone through your query with diligence and would like you to know that I am here to help. Let me explain using your own example of benadryl and bronchitis.

Bronchitis is a condition in which there is inflammation of the bronchi, which can cause a certain amount of narrowing of the respiratory tract making it slightly difficult to breathe.

Medication like benadryl (contains diphenhydramine) which is an antihistamine can cause a certain amount of bronchoconstriction due to its atropine-like action, which can further narrow the respiratory tract in individuals with bronchitis, thus result in severe breathlessness and some serious complications can result.

I hope I have explained things in a manner best understood by you. Please feel free to write back to me for any further clarifications, I am always here to help.

Best wishes.

Above answer was peer-reviewed by : Dr. Nagamani Ng

Follow up: Dr. Shoaib Khan (7 hours later)

Thank you kindly Dr. Shoalb.

Two clarification questions:

I. Do any other H1 blockers, or even H2 blockers, cause bronchoconstriction?

II. Are there any other pulmonary conditions in which antihistamines of any kind would be contraindicated?

Again, my thanks!

Answered by Dr. Shoaib Khan (45 minutes later)

Brief Answer:
Yes, there are a few listed antihistamines and a few pulm conditions

Detailed Answer:
Hello once again.

I. Yes, there are quite a few like pheniramine, chlorpheniramine, olopatadine, azelastine, etc.

II. Yes, all conditions that can cause inflammation or narrowing of the airways like asthma, bronchitis, chronic obstructive pulmonary disease, etc.

If there are any specific conditions or medications you wish to gain information about, I could certainly help you with that.

Awaiting..
Best wishes.

Above answer was peer-reviewed by : Dr. Arnab Banerjee

Follow up: Dr. Shoaib Khan (41 hours later)

Dr. XXXXXXX my thanks. :)

Can you tell me if Zyrtec, Allegra, or Claritin cause this bronchoconstriction effect we have been discussing?

Regards and thanks from XXXXXXX

XXXX

Answered by Dr. Shoaib Khan (9 hours later)

Brief Answer:
All three of them have a bronchodilators action :)

Detailed Answer:
Hello once again XXXXXXX

1. Zyrtec (with active ingredient cetrizine) has a bronchodilators action

2. Allegra (active ingredient fexofenadine) also has a mild bronchodilators action

3. Claritin (active ingredient loratadine) also has a bronchodilators action

Thank you so much for the good wishes, doubled and sent right back to you ma'am. :)

Best wishes.

Above answer was peer-reviewed by : Dr. Prasad

Follow up: Dr. Shoaib Khan (2 days later)

Thank you that is excellent!

So this would mean these antihistamines would be beneficial not detrimental for patients with allergies and also pulmonary inflammation.

Dr. XXXXXXX are there any other fast-acting H1 blockers that can be effectively used in lieu of Benadryl to treat allergies, and that do not have bronchoconstriction effects?

Thank you for your kind words!

Answered by Dr. Shoaib Khan (7 hours later)

Brief Answer:
Here are a few medications you can use safely XXXXXXX :)

Detailed Answer:
Hello once again XXXXXXX

Yes.

Here are a few second generation H1 antagonists that can be safely used in conditions like asthma:

+Loratadine
+Astemizole
+Terfenadine
+Cetrizine
+Levocetrizine

Third generation:

+Fexofenadine
+Norastemizole
+Descarboethoxyloratadine

I hope this helps. It was my pleasure, and please do not hesitate to write to me anytime should you need any assistance, even in the future you can just write a query down and just mention my name in it and it will be directed to me. But heres to hoping and praying you never have any medical issue at all.

Best wishes.

Above answer was peer-reviewed by : Dr. Prasad

Follow up: Dr. Shoaib Khan (5 hours later)

Dr. XXXXXXX my grateful thanks for your knowledge and encouraging words and prayers!

Are any of the above referenced H1 antagonist medications fast-acting antihistamines like Benadryl, and which can be used in lieu of such?

Answered by Dr. Shoaib Khan (8 minutes later)

Brief Answer:
Cetrizine, loratadine and fexofenadine

Detailed Answer:
Hello once again ma'am.

It's my pleasure entirely.

Yes; loratadine, cetrizine and fexofenadine are fast acting ma'am. :)

Get well soon

Above answer was peer-reviewed by : Dr. Arnab Banerjee