Top
10
Doctor insights on: How Long Should It Take For An Allergy Pill To Work

Share
1

1
How long should it take for an allergy pill to work?

How long should it take for an allergy pill to work?

1/2 to 1 hour: Some antihistamines require metabolism in the liver to be converted into the most effective form to block histamine. These antihistamines take at least 1 hour to become effective. However, some antihistamines like allegra, xyzal (levocetirizine) and Clarinex are already in the active form and begin to work as soon as they are absorbed which take about 30 minutes. ...Read more

See 2 more doctor answers
Dr. John Chiu
2,479 doctors shared insights

Allergies (Definition)

Allergies occur when your immune system is triggered by envirionmental factors it should ignore--for example, pollen in the air, or dander on a cat or dog--and creates cells to fight against them. An allergic reaction typically causes itching, congestion, or drainage, and ...Read more


2

2
Why is it that allergy pills don't work every time I take one?

Why is it that allergy pills don't work every time I take one?

Timing: Antihistamines work by blocking histamine receptors in your body. If the receptors are all full of histamine already (reaction has occurred), then there is nowhere for them to go and it will not make a difference in allergy symptoms. If you take them before exposure to allergens they can block the receptors and you will have less symptoms. ...Read more

See 1 more doctor answer
4

4
If i took an allergy pill(extra strength 1aday) at 2pm yesterday, it is 7:00 am and I am needing another, can I take now? At work have allergy to cats.

If i took an allergy pill(extra strength 1aday) at 2pm yesterday, it is 7:00 am and I am needing another, can I take now? At work have allergy to cats.

Depends: It is occasionally ok to take extra dose of antihistamine but if you are taking 24 hour antihistamine decongestant combination it would be too much decongestant. Check with your doctor for other medicines that might relieve your symptoms. If you have unavoidable cat exposure you may benefit from a visit to the allergist. ...Read more

5

5
Do over-the-counter allergy medicines work for oral allergy syndrome if you take a pill before eating?

Do over-the-counter allergy medicines work for oral allergy syndrome if you take a pill before eating?

No: The only thing that works for oas is allergy shots to reduce your sensitivity. I don't know exactly why that is, but i've never met a single patient who had found any medication that prevented oas symptoms. ...Read more

6

6
I took a allergy pill zyrtek but it doesn't seem to be working. How long can do I have to wait to take some bendryl?

I took a allergy pill zyrtek but it doesn't seem to be working. How long can do I have to wait to take some bendryl?

Symptoms: You did not describe any symptoms or what you are experiencing and what you expect. It is best on health tap to be specific and direct. ...Read more

See 1 more doctor answer
8

8
How long does it take a 25mg Benadryl (diphenhydramine) pill to start working on allergy?

How long does it take a 25mg Benadryl (diphenhydramine) pill to start working on allergy?

Should: Start working within the hour. But it is a low dose and sedating. You might try an Allegra or Claritin (loratadine) ( store brand ok) that is once a day and once in your system you won't be on a roller coaster of it working or not as long as you take it regularly. ...Read more

See 1 more doctor answer
10

10
Please tell me how long do I take medicine for a sinus infection and can I take it along with 24 hour allergy pill?

Please tell me how long do I take medicine for a sinus infection and can I take it along with 24 hour allergy pill?

If you have actual: Sinus infection then you would usually be prescribed antibiotics and would take the complete course of medication. ...Read more