Zyrtec (cetirizine) is an antihistamine approved for use in humans to treat allergy symptoms. In veterinary medicine it’s used in both cats and dogs for the same indication...and more.
For dogs, I’ll turn to Zyrtec when Benadryl (diphenhydramine) fails. Usually, these are the itchy dogs: the hot spot-ridden, flea allergic, food allergic and/or atopic (inhalant allergic). Except in older dogs whose kidney function I carefully screen before embarking on a course, Zyrtec has proved incredibly safe and moderately effective. The ability to buy it OTC and dose it only once daily for some dogs––not to mention its less drowse-inducing action––has enlisted my fandom.
The only drawback? Its brand name version is more expensive, meaning it tends to be pricier than drugs like Benadryl. And for a drug that sometimes has to be administered for weeks on end, that’s no small factor. Luckily, it's off patent now and you can purchase generics for significantly less than the prettily packaged stuff.
Moderate dog success notwithstanding, where Zyrtec really shines is in my kitty patients. Though it doesn’t work for all itchy cats, it does seem to help quite a bit––far more than Benadryl’s diphenhydramine and significantly more than chlorpheniramine (my former go-to antihistamine for cats).
The dermatologists on VIN (the Veterinary Information Network) seem to agree: Good, safe stuff for cats, this Zyrtec. Probably more effective than the alternatives. And definitely easier because, for cats, we now know that once-a day dosing is perfectly appropriate.
The best news for felines, however, is not just that Zyrtec seems to help for their itchiness, but also that it may help treat eosinophilic diseases.
What’s that, you ask? They’re a collection of [typically] skin, airway and intestinal diseases cats suffer much more frequently than dogs. They can cause stomatitis (oral inflammation), rodent ulcers (unsightly upper lip lesions), eosinophilic plaques (crusty sores), intestinal ulceration and diarrhea, bronchitis and tracheitis and asthma, among other problems.
Lately, it’s been determined that a significant percentage of cats affected by these eosinophilic diseases respond well to Zyrtec. Complete remission of symptoms is actually possible for some once this drug is initiated. So far, this seems to be true for all eosinophilic cases save those of the respiratory variety. (Who knows why.)
A recent case demonstrates the possibilities: A cat remanded to lifelong use of prednisone for her eosinophilic skin disease (manifested primarily in her ears and intestines) was weaned off this harsh, immunosuppressive steroid while Zyrtec was initiated.
I expressed tremendous concern that all the symptoms would almost certainly return, though perhaps at a more manageable level than before the steroid usage. Yet six months later there’s no sign of a break in her remission. No diarrhea. No ear lesions. Nothing. The cat is more playful and happy than she’s ever been.
Though this case is undoubtedly not the norm, the shocking success of it speaks to the need to study this drug in more detail. Currently, most of the evidence in favor of its use comes from the dermatologic community. Too bad the now-vast supply of it is primarily anecdotal.
Luckily, the human medical community has been active in amassing literature on Zyrtec and eosinophilic diseases, leading the veterinary community to begin more aggressively employing it in the hopes that one of the most frustrating feline disease complexes we see in cats can be successfully addressed.
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For a dog that has a bad histroy of allergies, have you seen better results with Zyrtec vs. chlorpheniramine? I didn't know that dogs could take Zyrtec and my vet never mentioned.
emily November 4th, 2009 09:18:32 AM
emily: I would tell my clients to give it a try. Some dogs definitely do better with Zyrtec. Most clients, however, don't find that it's worth the price differential. But if your dog happens to be among those that respond really well, it may well be worth that on-patent price.
Dr. Patty Khuly November 4th, 2009 09:29:25 AM
I wish I'd known about this a few years ago.
We managed eosinophilic granuloma in our beloved Kuttatoa for well over a decade. He was also hyperthyroid. Wonderful cat. Lived to be 17, but if we'd had something less harsh than the various steroids we tried, who knows?
I was always looking for some new therapy, some complementary therapy that was worth a try -- nothing.
The mouth ulcers were painful and very troublesome for him, not just "unsightly." (Didn't help his breath any, either.)
H. Houlahan November 4th, 2009 09:36:08 AM
At least in Kansas--and I would assume these things are universal--I've been able to get a generic of Zyrtec since January. I pay about $6 for 30 pills.
Meryl November 4th, 2009 09:38:49 AM
Zyrtec is available in generic form.
Shelly November 4th, 2009 09:51:05 AM
Meryl: My bad. Just checked. You're right. I'll amend the post to include your suggestion. I guess the issue is that I've been directing my clients to the brand name...therefore complaints about price. This is why a forum like this is so useful. Thanks!
Dr. Patty Khuly November 4th, 2009 09:51:58 AM
I've amended the post. Thanks you so much Shelly and Meryl.
Dr. Patty Khuly November 4th, 2009 09:57:02 AM
More food for thought: The 1:1 price comparison between cetirizine and diphenhydramine is not even the whole story. When you take into account that in my dog's case, 1 Zyrtec a day can replace 6 Benadryl pills, it makes Zyrtec/cetirizine even more affordable.
Shelly November 4th, 2009 10:07:33 AM
You can get generic Zyrtec (also generic Claritin) at www.healthwarehouse.com. There is no minimum order and no shipping charge. A bottle of 100 tablets of generic Zyrtec (10 mg.) is only $8.25. I've used this and generic Claritin on Cairn Terriers with itchy problems. Our vet recommended to start with the smallest dose (half or quarter of a tablet) and give it every 12 hours as it doesn't stay in the dog's digestive tract long enough for it to work a full 24 hours. If that doesn't fully help then try adding a bit more. I used generic Claritin this summer on a Cairn Terrier that came into rescue (www.CairnRescue.com) with a severe yeast and bacterial infection and complete hair loss. I put doggie jammies on her to protect her skin but she never once scratched herself raw. This has proved a Godsend to our rescue as we get in a lot of dogs with skin issues due to poor care.
I hope this is helpful to others.
Bonnie November 4th, 2009 10:10:51 AM
I'd sure like to know more about the dosage for cats with stomatitis. I'll be taking this to my vet. I have 4 cats with it and they really suffer despite having teeth pulled, steriods (which I very much dislike), etc.
Thanks
Sam
Sam November 4th, 2009 11:57:01 AM
Sam: I haven't had that much luck with stomatitis unless it's eosinophilic (not the typical) but some cats do respond somewhat. Given that it may at least help you reduce the steroid dose (they can be used in tandem), it's absolutely worth asking your vet about.
Dr. Patty Khuly November 4th, 2009 01:13:27 PM
I have used Zyrtec for myself and really appreciate how it works. I tried to save myself a few dollars and bought the generic, and found it does not work nearly as well as the name brand for me.
It might not be a bad idea to start pets out on the name brand and then switch to generic to see if it will work just as well for them, might save some headache if the generic doesn't work as well for the individual pet as the name brand does.
*fyi I generally buy generics for just about everything except Puffs tissues and Zyrtec
Connie November 4th, 2009 01:28:30 PM
Curious as whether you feel Zyrtec works better than Claritin?
My poor Lab is having a really difficult time right now re: allergies and being itchy. We don't know what she is allergic to - but I currently have her on 2 doses of Benadryl/day AND 2 doses of Claritin/day, which my vet recommended.
Erika November 4th, 2009 01:35:13 PM
Dr. Khuly,
Thanks so much for your answer. How do I know if it's eosinophilic or not? I don't remember any of the vets I've seen mentioning that.
Thanks
Sam November 4th, 2009 01:54:34 PM
I have been using Atopica (or generic cyclosporine) for several years now with my wire fox terrier. He still gets itchies even with that and his eyesight is very sensitive to bright light....one of the lesser known side effects of cyclosporine. This sounds like something to try. I'm glad you mentioned it. BTW - the $20 or less for Zyrtec is certainly a lot less than the $55 to $120 per month I am spending on Atopica/cyclosporine.
Carol November 4th, 2009 02:04:55 PM
I have to say I wasn't impressed with Atopica at all but then the cost did drive me toward finding the underlying causes of my Shiba's allergies. Even so, she still has occasional allergies issues so maybe I need to try Zyrtec and see if that should also be in my "arsenal" :)
PJB November 4th, 2009 02:25:24 PM
I have a neighbor whose cat recently died after suffering from severe allergies every summer and fall and treatment with long-term steroid use, and -- WTF?! -- Ovaban. This poor cat was just covered with sores and he just itched and scratched constantly. I wish this news had come in time for her to ask her vet about. But if it can save even one more cat from a miserable life, I'm glad I know about the anecdotal evidence of Zyrtec's effectiveness now.
JaneA November 4th, 2009 03:15:32 PM
Intriguing, thinks. I'll mention this to my vet. The "allergic little dog"'s bloodwork was not beautiful when he was started on Temaril-P, and I wonder if that's why they didn't suggest Zyrtec; he might not be a candidate.
Benadryl does help him, but makes him a zonked little dog. He does pretty well on Temaril-P, but the vets have mentioned a few times that they're not thrilled about the steroid.
Galadriel November 4th, 2009 03:52:45 PM
I have a cat now with severe itching. He has been this way forever and he is about 14 now. I have taken him to a vet dermatologist and ran lots of tests, tried different meds, diets, etc and nothing works.
He is now getting a steroid shot every 5 weeks or so which I also hate but it does help some. I'm afraid if I ask my vet about it, he may just poo poo me. I am the same lady that has a cat that was prescribed Piroxicam for bladder issues. She is no longer on it.
If I were to give Zyrtec to my cat who weights about 12 lbs, how much and how often would I give it to him? If you don't feel it proper to give this info instead referring me to my vet I understand.
Jan November 4th, 2009 06:15:50 PM
Maybe I missed it in the article, but how many milligrams would you give a 10 pound dog? Or a 40 pound dog? The generic Zyrtec that I take for myself comes in 10mg pills. This is awesome news since I can share with my dogs. Thanks for posting!
Eva Maria November 4th, 2009 06:24:46 PM
Iam very carefull about what I give my cats for medicen, I want my vet's opinion and even then I will ask a lot of questions. http://tinyurl.com/4xvkkk
I have 46 house cats of my own (most are rescues).I would like to exchange website links with you. My website donates 10% of all it's profits to the Addison County Humane Society in Middlebury, Vermont. Website is http://www.petloverspalace.com Title- Pet supplies and accessories for dogs, cats and other small animals.
Jeffrey New November 4th, 2009 07:45:17 PM
Sorry for the thread hijack, but here is a story idea:
http://www.avma.org/press/releases/091104_H1N1_Iowa_cat.asp
Apparently, we can give H1N1 to our cats. Not a good thing.
Stefani November 4th, 2009 07:47:46 PM
"Temaril-P, but the vets have mentioned a few times that they're not thrilled about the steroid" Yep, we tried that one too. I agree with those vets :)
H1N1: And when do I get to say "I told y'all so" :) I still don't get this part: "no indications that the cat passed the virus on to any other animals or people". Now how do they know who got it and in what order? Why do they stick to this concept that zoonoses is primarily a one way transmission street? (Me, not going to panic over that part since it seems far more likely I'll give diseases to my critters than they to me since they don't leave the house and interact with others as often as I do but this one way assumption seems pretty unfounded and absurd to me.) I so hope this "reminding pet owners that some viruses can pass between people and animals, so this was not an altogether unexpected event. Pet owners should monitor their pets' health very closely, no matter what type of animal, and visit a veterinarian if there are any signs of illness" spreads wide and far instead. .................... Hm, time to dig out those masks and gloves before I go shopping tomorrow :)
PJB November 4th, 2009 08:13:50 PM
Galadriel: Zyrtec is much less stressful than Temaril or any other steroid. Hands down. It's nowhere near as problematic. If he can handle Temaril he can handle Zyrtec. Almost always, anyway.
Stefani: You hijacked tomorrow's post! ;-) I'm getting to that.
Jan and Eva:I'm always careful about omitting dosages. That's because I wouldn't want anyone to construe this post as offering veterinary advice without an appropriate (and legal) relationship. Ask your vet.
Sam: Biopsy or cytology. Give it a go. Or ask your vet about trying the Zyrtec for a week.
Dr. Patty Khuly November 4th, 2009 08:18:32 PM
Doc, I understand that line about not giving dosages BUT some outside guidelines would be nice since it isn't like we can look up off label dosages :) Or maybe just it's lower per kg or higher per kg than humans? Personally, I do the math for the human dosages just to make sure I'm not being advised to OD my critters because someone's having a bad math day. Shoot, we do the math around here for humans. My son is a body builder, twice my size and all muscle and that one-size-fits-all "adult" human dosage doesn't make much sense with some of these drugs!
PJB November 4th, 2009 09:04:10 PM
Oh, very interesting! I have a dog with allergies (food and environmental). Benadryl doesn't work for her, and while the Claritin is working, it's nice to know there's something other than steroids to try. AND I have a cat with eosonophilic plaque. My vet has treated those with prednisone, but given that he's a super fat cat (working on it, I swear; my other cat and my dog are all ideal weight), and given that we have the worst pet health luck EVER, the vet is concerned about him developing diabetes. I will ask about the Zyrtec.
Crystal November 4th, 2009 10:00:42 PM
Hi there,
I own and run the Feline Stomatitis Yahoo Message board and was just sent a link to this article, and found it interesting. In regard to it helping stomatitis, can you tell me, or post links to where I can find more information about this working for cats with Stomatitis? There are some desperate people trying to help their poor cats with this AGONIZING disease, and anything newly written about the disease is something that we like to share with each other. My email is shane@thetoothfairyllc.com
Thank you...
Shane
Shane November 5th, 2009 01:52:31 AM
Shane: Unfortunately, it's all anecdotal. That's the problem. I cannot say that it will help cats with stomatitis based on any research yet available. Even anecdotally, it seems to help primarily those whose stomatitis is related to or concurrent with eosinophilic diseases like eosinophilic granuloma complex-related plaques and rodent ulcers.
Interestingly, more work has been done on the pharmacokinetics of this drug in cats (study cited above) than on its effectiveness. It speaks to the fact that it's being successfully used by veterinarians, but we're a long way from being able to tell you the whys and whens of how it works.
Dr. Patty Khuly November 5th, 2009 05:13:39 AM
PJB: Interestingly, the doses for cats and dogs are pretty similar to those we give humans. I normally prescribe 5 mg once daily to my kitties and 5-10 mg twice daily to my canines.
You're right, PJB. If I urge you all to buy Plumb's Veterinary Drug Handbook with all its dosage information (look in my little Amazon widget and you'll find it's one of my selections), why not tell you what I do for my patients?
Dr. Patty Khuly November 5th, 2009 05:21:36 AM
Claritin vs. Zyrtec...again, tough to say which is best, though I have noticed that VIN dermatologists seem to talk more about Zyrtec than Claritin. That's a solid...dunno.
Dr. Patty Khuly November 5th, 2009 05:24:32 AM
While antihistamines can help some pets, I prefer a more natural approach to keeping my allergic pets comfortable. Many therapies (fish oil, antioxidants, herb, homeopathics, frequent bathing, etc.) work GREAT and don't have the side effects that can be seen with long term use of conventional medications.
Shawn Messonnier DVM
Dr. Shawn
www.petcarenaturally.com
Shawn Messonnier DVM November 5th, 2009 05:55:07 AM
Hi Dr. Shawn! I'm inclined to mostly agree with you but, despite doing much of what you mention, my Shiba and others still sometimes need a little extra or a bit of "now" relief :)
Plano? Hm, certainly closer to Houston than Miami is. Guess I'll have to check out your website for starters.
PJB November 5th, 2009 07:16:51 AM
Shawn: Are you the same as the Shawn P. Messonnier that wrote a neuro handbook I own?
Dr. Patty Khuly November 5th, 2009 08:42:09 AM
Dr. Khuly, I'd love to know, in your opinion, what risks are associated with cats and dogs taking antihistamines daily for long periods of time or even a life time? I have a dog and a cat with allergies (I have allergies too) and I've never really been able to get a straight answer from my vet about the risks and side effects of, for example, giving my dog 125-150 mg of diphenhydramine twice a day almost year round. It seems to me that taking high doses of a drug, daily, for life, is going to have consequences. I understand that we're using antihistamines "off label", but veternarians have been doing it for so many years that surely some observations have been made? I'm not about to let my dog suffer, but I'd like to know whether I should be concerned and what I should look out for. Perhaps this could be the subject of a future blog post?
Lindsey November 5th, 2009 12:59:32 PM
My cat spent a couple of months last summer fighting eosinophelic ulcers in her mouth and on her lips. I hated putting her on prednisone for weeks on end. I'm glad there's an alternative.
Diane November 5th, 2009 07:06:30 PM
My pug Lulu has had allergies her whole life and I finally broke down and got her allergy tested. She is allergic to pretty much everything in the enviroment! So I started her on allergy vaccine and the dermotologist recommended me giving her zyrtec. I got the generic at walmart and it has worked wonderfully for her! No more skin infections and she doesn't itch herself crazy anymore!
loveofpugs November 5th, 2009 07:22:26 PM
I was wondering if you believe Zyrtec is ok to use in cats that are pregnant. I have a female, who is pullng hair out where butt n tail meet, she does not have mites or fleas so I thought about trying Zyrtec, however it is becoming obvious she is pregnant.
I would also like to know how young of a cat Zyrtec may be given ie kittens.
One more q, has it been tried in cats with caudel stomatitus?
THX BUNCHES!
ctipling November 9th, 2009 03:34:03 PM
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