Question 1

does allegra (fexofenadine) build up in your system?

Accepted Answer

Allegra (fexofenadine): Needs about 45 minutes to start working and wears off within a day or 2, so you need to take it daily for maximum effect.

Question 2

how long does it take allegra (fexofenadine) to leave your system?

Accepted Answer

Antihistamines: The antihistamines Allegra (fexofenadine), Claritin (loratadine), and zyrtec (cetirizine) can last in your body for more than a week. Most allergists want these medications discontined for a week before they perform skin testing. Some persons are 'slow-metabolizers' and these drugs can be in your system much longer.

Question 3

hi i have had cold systems for over a week and i was wondering what medications i can take? also can i take allegra in the afternoon?

Accepted Answer

Cold symptoms : You can take most any OTC medications that treat your symptoms. Allegra can be taken at anytime time of day but should be consistent.

Question 4

i accidently took two 24hr allegra d  on may 1 still have some side effects how long will the med will stay in ur system ?

Accepted Answer

Probably 24 hrs: This dose is fine since Allegra has a high margin of safety.  I do not expect much side effects at all . The biologic effect will last around a day but there may still be traces of the drug present in your body for a couple more days.

Question 5

i was told that allegra can give a false positive on a urine drug test so my question is how long will it be in my system?

Accepted Answer

Allegra: Allegra won't alter your urine drug screen. Perhaps Allegra-D that has a decongestant in it may. Typically it may linger in your urine for 4-5 days.

Question 6

how much allegra is safe on a daily basis? my system needs a break from claritin (loratadine) and zyrtec apparently, but 1 allegra is not working fully.

Accepted Answer

180mg: 180 mg allegra (fexofenadine) is maximum dose. If you are needing antihistamine daily, hopefully you have seen an allergist.

Question 7

does allegra (fexofenadine) 24 hours (not with d) surpress your immune system? can i get blood work (cbc w/diff) done while on allegra (fexofenadine) and have it be accurate?

Accepted Answer

No: Allegra (fexofenadine) is an otc non-sedating antihistamine and as such down regulates the release of histamine from mast cells in the tissue or decreases the effect of histamine that is released.  I do not think it would significantly suppress the immune system which is primarily lymphocyte function.  You can get blood work.  The only thing, you can not do is get skin testing for allergies while on this drug.

Question 8

i took sudafed 24 hour and  allegra 12 this morning now i have dry mouth and throat . badly  how much longer will it last i'm having trouble sleeping?

Accepted Answer

Sudafed: unfortunately insomnia is a known side effect of the drug, doesn&#x27;t affect all people who use it. The dose would stay in your system may be for a day, meanwhile avoid all sources of caffeine for now, as it would add up to the problem, wish you well

Question 9

can i take allegra 120 twice a day .

Accepted Answer

Most likely: But this would make side effects more likely - dry mouth and eyes for example, perhaps sedation / tiredness. Might think of mixing medicines from different classes if bad allergies are the issue. A primary care provider can help in this regard.

Question 10

is expired allegra (fexofenadine) safe?

Accepted Answer

Expired medication: Typically, when a medication expires, it's because it loses its potency or effectiveness.  There are some medications that, with time, do breakdown with time into harmful substances.  Check with your pharmacist to make sure.  I would not recommend taking any expired medication.

Get Virtual Care

For Businesses

About Us

HealthTap Online Primary Care Doctors Accepting New Patients

Doctor answers about:

How long does allegra stay in your system

A member asked:

Does allegra (fexofenadine) build up in your system?

A member asked:

How long does it take allegra (fexofenadine) to leave your system?

A member asked:

Hi i have had cold systems for over a week and i was wondering what medications i can take? also can i take allegra in the afternoon?

A member asked:

I accidently took two 24hr allegra d on may 1 still have some side effects how long will the med will stay in ur system ?

A member asked:

I was told that allegra can give a false positive on a urine drug test so my question is how long will it be in my system?

A member asked:

How much allegra is safe on a daily basis? my system needs a break from claritin (loratadine) and zyrtec apparently, but 1 allegra is not working fully.

A member asked:

Does allegra (fexofenadine) 24 hours (not with d) surpress your immune system? can i get blood work (cbc w/diff) done while on allegra (fexofenadine) and have it be accurate?

A member asked:

I took sudafed 24 hour and allegra 12 this morning now i have dry mouth and throat . badly how much longer will it last i'm having trouble sleeping?

A member asked:

Can i take allegra 120 twice a day .

A member asked:

Is expired allegra (fexofenadine) safe?

HealthTap Online Primary Care Doctors Accepting New Patients

Telemedicine

Primary Care

Manage Your Conditions

Women's Health

Children's Health

Men's Health

Senior Health

Wellness, Prevention & Lifestyle

Sexual Health

Mental & Behavioral Health

Travel Medicine

Urgent Care

Didn't find what you're looking for?

More of what we treat

Allergies

Antibiotics

Asthma

High Blood Pressure

Prescriptions

Type 2 Diabetes

For Businesses

Company

Health Content

Join Us

Download HealthTap

Questions?