Question 1

what is the highest dosage of antihistamine that one person can take at one time?

Accepted Answer

Antihistamines: Safety of high dose medications is often unknown. Our experience comes from case reports of persons who intentionally or accidentally consumed unusually excessive quantities. When Claritin (loratadine) was first investigated, safety studies were done at 40 mg (4 times the current recommended dose). We take 10 mg because effectiveness is not significantly different between 10 mg and 40mg.

Question 2

how many milligrams of antihistamine can a person take at one time?

Accepted Answer

Unclear: Different antihistamines have different potencies.  10 mg of Zyrtec is equivalent to 180mg of Allegra (fexofenadine).  Mg doseage as in all medicines are drug specific.  In regard to toxic levels, each has it's own known limit.  However too much antihistamine can lead to deadly arrythmias/  Please use the recommended dose.

Question 3

can an antihistamine like actifed kill you if you take too many at one time?

Accepted Answer

Yes: Actifed is more of decongestant. Yes it may harm you.

Question 4

can you take generic multi symptom night time medicine with night time thera-flu? i don't usually get drowsy from just one dose of antihistamine. i have adhd so it's hard for me to get sleepy from that. so is it okay to take both?

Accepted Answer

No: Those preparations contain multiple drugs similar to thera-flu, the problem isn't with antihistamines only, other components could interact, or interact with whatever medicines you are on or if you are under treatment for adhd, please consult your doctor and read the labels carefully, good that you asked , always exercise caution with multiple medications,

Question 5

is it safe to take an antihistamine like zyrtec daily for my dermatographia? will i need to increase the dose over time?

Accepted Answer

Dermatographia: is usually a "lifetime" condition. Antihistamines are sometimes effective and there are new developments  in the treatment of eaosinophils ( first "cousins" of mast cells the cells felt to be involved in the condition) Hope this is helpful!

Dr Z

Question 6

i am suffering from maxillary sinitius from last one month. my doctor told me to use antihistamine nasal spray 2 time a day. but sometime i do not feel the need of taking it, should i take it or not. can i use it for 2 weeks?

Accepted Answer

: Not sure what symptoms you are having but, if the doctor who examined you prescribed an antihistamine nasal spray, then take it as prescribed. It is fine to take it for 2 weeks. Hopefully, the doctor treating your sinusitis is going to see you again to make sure your symptoms and sinusitis resolve. If your symptoms are gone, then perhaps you can stop the nasal spray-call your doctor and ask!

Question 7

is it ok to take clorazepate with an antihistamine? the dosage is 3.75mg.

Accepted Answer

Watch for drowsiness: The combination can cause increased drowsiness. Please do not drive while taking both. Avoid the use of alcohol in combination. The clorazepate can be habit forming.

Question 8

what dosage of antihistamine should i take to resolve a mild food allergy reaction?

Accepted Answer

Any recommended: Dosage of any OTC antihistamine, either first or second generation, will be effective,  more important though is avoidance of re-exposure to the offending food till problem is sorted out. Keep antihistamine handy for accidental exposure, if severe reaction, keep epipen (epinephrine) handy too, see your doctor/allergist if the problem is bothersome, best wishes

Question 9

what is the best time to take an antihistamine?

Accepted Answer

Any time: You can take antihistamines any time of the day.Take them same time of day everyday.

Question 10

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?

Accepted Answer

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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Doctor answers about:

What is the highest dosage of antihistamine that one person can take at one time

A member asked:

What is the highest dosage of antihistamine that one person can take at one time?

A member asked:

How many milligrams of antihistamine can a person take at one time?

A member asked:

Can an antihistamine like actifed kill you if you take too many at one time?

A member asked:

Can you take generic multi symptom night time medicine with night time thera-flu? i don't usually get drowsy from just one dose of antihistamine. i have adhd so it's hard for me to get sleepy from that. so is it okay to take both?

A member asked:

Is it safe to take an antihistamine like zyrtec daily for my dermatographia? will i need to increase the dose over time?

A member asked:

I am suffering from maxillary sinitius from last one month. my doctor told me to use antihistamine nasal spray 2 time a day. but sometime i do not feel the need of taking it, should i take it or not. can i use it for 2 weeks?

A member asked:

Is it ok to take clorazepate with an antihistamine? the dosage is 3.75mg.

A member asked:

What dosage of antihistamine should i take to resolve a mild food allergy reaction?

A member asked:

What is the best time to take an antihistamine?

A member 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?

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