# advice on zyrtec dose



## bbuzz (Aug 8, 2010)

I was wondering if some of the more knowledgeable forum members could advise on Zyrtec dose?

My old gold has had some skin issues of late. We had a vet appointment Friday and in addition to the medicated shampoo/conditioner, rilexine and macrolone the vet asked us to administer some antihistamine. Unfortunately in the rush he forgot to hand us the paper advising the dose. So I rang up Friday and the front of office called back to say the dose is 20mg a day.

I went out and bought some zyrtec (10mg), however on the box the dose for a human is one tablet every 24 hrs. 20mg every 24 hrs sounds like to much to for sash who weights 29kg. 

Can anyone please advise if 20mg is the correct 24 hourly dose for Sash? At the current time the other treatment has solved the itching, could anyone advise if zyrtec is necessary or is it worthwhile as it provides and extra boast to the treatment.

I read a bit of information concerning that different brands of antihistamine can be hit and miss concerning effectivity and that we may have to trial a few. What are other peoples experience regarding finding the right antihistamine brand? Also how often do you give the antihistamine? Just when the dog starts showing symptoms or during the allergy prone season (im guessing this depends on the individual?)

Sorry about all the questions. The vet had to rush off to tend to a nasty hit and run on some poor pup, so we didn't really get to cover everything concerning the antihistamines. 

Thanks in advance!


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## bbuzz (Aug 8, 2010)

Does anyone give antihistamine?


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## iansgran (May 29, 2010)

Don't know about the dosage for zyrtec but why not use the search to see how much folks give benedril, because that is often recommended. And I believe, but am not certain the dosage is larger than for humans in that.


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## bbuzz (Aug 8, 2010)

Ok I'll try that. Thanks heaps for taking the time to respond, I appreciate it. The vet will be in tomorrow afternoon, so at worst I'll be able call then.


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## Sienna's Mom (Oct 23, 2007)

We recently had Sienna in to the vet for a skin bump issue that became much more involved than it should've been.

She did have a bit of itchy reaction to an area that was shaved and the vet said 50mg of Benedryl every 8 hours. Sienna weighs about 80 pounds.

I do think you should probably ask your vet to be sure though. Good luck, skin issues can be very frustrating!


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## Dallas Gold (Dec 22, 2007)

I don't have an answer about Benadryl dosing, but I did have a discussion a couple of weeks ago with the vet we use about antihistamines and she gave me a list (in order of use) of the antihistamines that she finds works best for dogs and the order she recommends:

1. Chlorpheniramine (we get ours at Walmart as the generic at $2.96 for 100 tablets) dosed every 4 hours. For mild days we give Toby a dose in the a.m. and then in the p.m. On bad pollen days we give a noon dose.

2. Hydroxyzine (prescription)

3. Zyrtec

4. Benadryl

She cautioned that dosing for each of these is different so be careful. She also cautioned to make sure that the antihistamine doesn't contain added decongestants, which so many human meds add.

If you get the proper zyrtec dose would you mind posting here? Thanks!


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## artbuc (Apr 12, 2009)

This is from a recent post I made on the health forum:

"Efficacy of antihistamines in dogs is generally not too good and highly variable. What works in one dog may not do squat in another. Clemastine (Tavist) works for 30% and cetirizine (Zyrtec) for 18%. For reasons not understood, antihistamines in dogs chemically degrade quickly so you can give large doses. Talk to your vet or dermatologist to see how much you can safely give. Rocky's dermatologist said 1.34mg clemastine 2-3x per day was fine. According to a study in the Canadian Veterinary Journal, cetirizine protocols vary widely from 2.5-10mg/dog, q24h, up to 1.1 mg/kgBW, q12h. This particular study used 1mg/kgBW, q24h, which did make 2 of the 22 dogs mildly sick for the first day or two although it appears that the vomiting in one of those two dogs was caused by an unrelated condition. Hydroxyzine is available from your vet (Rx only). It did nothing for Rocky."

The title of the paper is "Treatment of canine atopic dermatitis with cetirizine, a second generation antihistamine: A single-blinded, placebo-controlled study" published in May 2004. 

Based on this paper, I would say 1mg/kg of body weight once per day would be completely safe but I am NOT a vet!!!

I believe clemastine (Tavist) has the highest success rate - surprised your vet didn't mention this one.

PS. cetirizine hydrochloride (Zyrtec) is a metabolite of hydroxyzine.


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## vrmueller (Jun 14, 2008)

Just saw this post. We tried Zyrtec for Ruby this past May and the vet prescribed 10mgs (with 2 pills) 1 time a day. Ruby is is 57lbs. She was on it for a good month with no real improvement.


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## artbuc (Apr 12, 2009)

vrmueller said:


> Just saw this post. We tried Zyrtec for Ruby this past May and the vet prescribed 10mgs (with 2 pills) 1 time a day. Ruby is is 57lbs. She was on it for a good month with no real improvement.


About .4mg per kg body weight if I did my math correctly, 40% of what they used in the study. If your vet approved, you could probably increase that dose by 4X (20mg twice per day). Antihistamines offer little hope for dogs with serious atopy. My experience and research suggests the most they do is reduce the amount of steroids required to control itching.


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