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Menlo Park, CA
A 26-year-old male asked:

i know it is not recommended to take more than one antihistamine pill per 24 hours, but some only last ~8 hours. which ones lasts for 24 hrs?

1 doctor answer2 doctors weighed in
Dr. Michael Palumbo
Allergy and Immunology 23 years experience
Xyzal (levocetirizine) and Clarinex: From experience some of the newer antihistamines such as Xyzal (levocetirizine) and Clarinex seem to be effective for longer time periods. Most antihistamines however peak in effectiveness in the first few hours and start to wear off after 12-15 hours.

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Similar questions

CA
A 27-year-old member asked:

Is there a homeopathic remedy which acts as an antihistamine?

4 doctor answers12 doctors weighed in
Dr. Michael P Vaughn
Allergy and Immunology 34 years experience
Homeopathy: Homeopathic medicatios may have been appropriate for our ancestors however, "natural" does not mean "safe". A natural compound often contains hundreds of chemicals, many of which have not been studied. These "natural"complounds are not investigated by the fda for safety. Take a well studied medication that has been fda approved if you want defined safety and efficacy.
A 32-year-old member asked:

What is the average time needed for an antihistamine to begin to work?

2 doctor answers5 doctors weighed in
Dr. Steven Machtinger
Allergy and Immunology 44 years experience
45-90 minutes: Antihistamines taken by mouth begin to work in about an hour but may take longer if you've just eaten. Antihistamine nasal sprays (astepro, patanase) begin to work in 30 minutes. An antihistamine injection, usually diphenhydramine, sometimes given for a severe allergic reaction or anaphylaxis begins to work in a few minutes.
A 39-year-old member asked:

Is there an herb which can be used as an antihistamine?

2 doctor answers3 doctors weighed in
Dr. Giana Nicoara
Allergy and Immunology 28 years experience
Yes: Butterbur has antihistamine-like effects. It can be found at health food stores.
CA
A 31-year-old member asked:

When should you take an antihistamine?

2 doctor answers7 doctors weighed in
Dr. Alex Martinez
Specializes in Allergy
For allergies: Antihistamines help the most with sneezing, watery drainage, and itching which are often seen with allergies. Older antihistamines (like benadryl) can make people sleepy and should be used with caution; newer antihistamines (like Claritin (loratadine) & allegra) are less likely to be sedating. Because of their drying effect, some doctors recommend avoiding antihistamines during a respiratory infection.
A 45-year-old member asked:

How does antihistamine affect your ability to hear?

2 doctor answers5 doctors weighed in
Dr. Mike Bowman
ENT and Head and Neck Surgery 19 years experience
Not directly: Allergies can cause eustachian tube dysfunction (etd). Etd can cause fluid build up in the middle ear which can dampen the hearing. See your ENT for evaluation of your hearing and treatment if you suspect such a problem. Best wishes.

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Last updated Nov 2, 2019
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