Our daughter is under 6 so she gets 5 ML per day.  But we have always found that splitting the dose in 2 works better.. 2.5 ML in the morning and 2.5ML in the evening.  On occasion when her mould allergies are really bad, we also gave her benedryl along with cetirizine. 

My doctor has told me that, for adult or child, you occasionally can take a double dose, but not on an ongoing basis. 

I'm interested to hear if you can mix antihistamines on an ongoing basis. That could help in the spring! 

My ds is younger than your dd, but we did have success with breaking up the Zyrtec dose, 1 tsp in morning, and 1 at night during really bad spring allergy season last year.

we've double-dosed our 8 year old, under instructions from the doctor...and topped it off when benadryl, when needed to control those *^$^#(&# hives.....

Missed your question about the mixing - when the doctor prescribed me the Zyrtec, it was on top of Claritin-D, and I've used it with doctor's permission on top of Allegra-D as well.

Thanks to you all.  DD is 12 (13 in a few days) with adult mass - she's a very muscular 5' 7" (and still growing  ), but I'm guessing still metabolizing the Zyrtec like a child.  I think I'll dose her when it wears off, as long as it's been 12 hours since her previous dose, for a few days and see how she feels.   

Adults definitely metabolize the second gen antihistamines more SLOWLY than children do.  There obviously isn't a super-clear dividing line there, either.  It just gradually slows.


Our allergist has knowingly doubled cetirizine dosing (and piggypacked first gen antihitamines on top, too) for breakthrough symptoms.

In the wake of a reaction, we OFTEN double-dose for as long as five days or so.

I've done more.  Allergist said ok for hives, but did it for seasonal allergies too.

We double dose DD when she needs it.  Not routinely, mind, and I really caution doing this for anyone under ~180lbs for more than a few days in a row...


IMMV, NO advice. 

DD is about 90 lbs.

I've done 10 mg of Zyrtec twice a day for hives - if I remember correctly, I first had it prescribed that way back when I was in high school.  For whatever reason, 24 hour meds don't seem to work well with me - I seem to need twice daily dosages of all of my meds.  Not just allergy meds, but my GERD meds and heart meds too.

DD has been really suffering from her seasonal allergies the past few weeks.  Zyrtec seems to help but the effect wears off about 12 hours after taking it.  She takes 10 mg and I know the dosage is 10 mg/ 24 hours.  So, has anyone ever been told it's okay to take more?  Would it be better to give 5 mg am/pm instead?  Though if 10 mg isn't lasting, I doubt 5 mg would be enough.  Can I mix Zyrtec with another antihistamine like Claritin and take one in the morning and one at night?

I will call her doctor, but just wanted to hear what others have done, too.  Thanks