antihistamines

I give my lab benadryl (generic version) 2 x a day and have for the better part of the last year.  She has so many allergy problems, and it does seem to keep a lid on them a bit.  They are considered safe but there are a few different kinds and some work better than others.  It seems to me that the biggest mistake many people make is trying to give too low of a dose and/or not giving it often enough.  It's really important to get the histamines calmed down so the body isn't reacting in all kinds of ways, like itching, licking paws, ear infections, etc.  Hopefully between the antibiotics and the antihistamines, you'll be in good shape soon.

Shelly; here is a link to the dosage for different antihistamines according to the dog's body weight;
                   [linkhttp://www.utskinvet.org/pdf/antihists.pdf]http://www.utskinvet.org/pdf/antihists.pdf[/link]
 
   I haven't tried Hydroxyzine but Sally's dog Trudy is taking it and it works for her. I posted some suggestions for you about ways to help your dog's itching besides antihistamines in the thread "Blood Test For Allergies" including the titles of two books written by holistic veterinarians who suggest several natural treatments including supplements to help dogs with allergies. There are many people here who have good information to share concerning good shampoos for itching dogs and other things that can help so please ask any questions you want to. There are many things you can do to help your dog and allergen immunotherapy may not be necessary.

There are 4 different 'types' of allergies generally and then different sub-types from there.
 
1.  Atopic (hayfever, seasonal stuff and inhaled stuff like dust, mold, mildew that can be anything from dust mites to wallpaper or a damp cellar) - this is a wide range of stuff, but since your dog is showing ear problems (OFTEN allergies -- particularly atopic and sometimes food allergies -- will attack the delicate membranes in the ear) and red eyes (classic seasonal allergy symptoms);
 
2.  Food allergies -- often those go hand in hand (or paw and paw) with Atopic allergies -- the seasonal allergies rile everything up with every breath they draw and food sets it off)
 
3.  Contact allergies -- not just the pollen but the actual oils in grasses and certain plants and even stuff like carpet fibers, but it results in little tiny blisters more like we'd react to poison ivy - which IS a contact allergy)
 
4.  Flea allergy -- very specific patterning - starts at the base of the tail and crawls up the back and down the back legs and then will generalize all over -- the dog is actually allergic to the flea *spit* - so one bite from a flea that dies right off can still make the dog miserable).
 
The atopic is the biggest category (and often the toughest to deal with).  But particularly seasonal allergies can be helped with antihistamines and maybe some other supplementation or even other modalities like actupuncture or homeopathics.  Antihistamines often won't 'cure' but can often at least help.  If you think about a dog's sensitive sense of smell and the fact that they have a whole secondary organ of smell (Jacobsen's Organ) that is miles of delicate tissue super-folded in the cavity above the mouth but below the nose - it's no wonder these are horrible to treat. 
 
Different antihistamines tend to be for different 'things' -- but additionally individual dogs often react differently to different anti-histamines.  Hydroxazine is an older anthistamine (it was developed about the same time as Benedryl/diphenhydramine) but it's no longer given to humans (causes emotional side effects) so it's prescription only.  Vets often like to dispense that one so they control the dose. 
 
But there are a bunch of antihistamines dogs can take -- 'brand' names you might be familiar with - Chlortrimeton, Tavist, Dimetapp as well as Benedryl.
 
BUT - they are all dosed totally differently -- so the 1-2 mg/lb body weight two to four times a day that is the Benedryl dose is for that ONLY.  But you can find a pet PDR at most libraries that might help you.  Or the Pill Book Guide to Medication for your Dog and Cat (Amazon still sells those, last printed 1998, Dell Reference book) can be a huge help.

I've used Hydroxyzine  but have found that Diphenhydramine 25 mg works better. Trixie gets 1/2 tablet 3 x daily.  It helps with the scratching.

Thanks so much everyone for all your help and all the information.  I really appreciate it.  My dog is about 33 pounds and is getting 25mg of antihistamines.  Do antihistamines make a dog tired or thirsty? 
 
So just to clarify, antihistamines don't cure the allergy, it just helps with the symptoms.  Is that right?

I give a Tavist every few days to my allergic Tzu. It does help alleviate the symptoms but of course it isnt a cure. I like the Tavist because it doesnt cause the drowsiness in him like the others we have tried. Good luck! GRR, allergies!!!!!!!

Shelly, you're right -- nothing 'cures' an allergy.  I'm allergic to fresh basil and I will always BE allergic to fresh basil.  Even if I'm 'desensitized' (like shots) ... it's not a 'cure' ... it's making you 'less' sensitive.
 
The thing with antihistamines is you have to give it consistently in order for the body to process the histamines as they come in.  So giving it daily thru the season or as long as needed is important.
 
Just FYI -- ziggynemo -- if you are givng a WHOLE Tavist to a shih tzu??  wow --
 
The dose for Tavist/clemastine is 0.025 to 0.05 mg/lb -- and the over the counter pills are 1.34 mg or 2.65 mg.. 
 
So the small pills would have to be  a 54 pound shih tzu for a 'normal' dose or a maximum HIGH dose for a 27 lb dog twice a day.  That's a pretty big shih tzu!  (or you're over dosing).
 
I honestly can't stress enough -- when you begin giving them most any antihistamine, they will be sleepy, but it's a side effect that goes away after a few days.
 
But yes, typically it will make them sleepy (at first) but it will always make them thirsty and do *not* deny them water.  That's really important or you can damage the kidneys.
 
Giving it once a day in a high dose doesn't 'help' because the drug lasts 12 hours in the body.   

I would recommend doing an allergy screening on your dog.  That way you know exactly what is the cause of the allergy (s).  We see A LOT of allergy dogs at the hospital I work at and a lot of them, to me, seem that they could be figured out if the proper testing was done...but of course ppl usually never want to do it so we just continue to treat the symptoms and push the underlying problem under the rug.

I'm sorry, but I have just a few more question.  You guys are great and so informative.  I was just wondering if the more the dogs take the antihistamines, does that mean they will require more of them or higher doses?  I'm wondering if the body gets used to the drug, if more of it will then be required.  Also, if it is given for a long period of time and they the dog comes off the pill are there any side effects, like withdrawal?  Also, could antihistamines make a dog dizzy?  How would I know if he is dizzy from this pill? 
 
I always have fresh water for my dog and constantly changing his water and putting fresh water in his bowl.  He does seem more thirsty since he started this med, but doesn't really seem tired on it, but I give it at 8:30 at night, so he's sleeping anyway.  My doctor said to give it twice a day, but I wanted to start out once a day to see how he reacts to it first.  Also, I am still thinking of getting him allergy tested, but am waiting for his current infection to be gone first.
 
Thanks again for all your help.  I love me dog as if he were my child (which he is), and I just want the best for him and all the information I can have.  I don't like putting meds into his body unless I'm fully informed and it's in his best interest.  I'm always asking tons of questions to my vet.

The dose for Tavist/clemastine is 0.025 to 0.05 mg/lb -- and the over the counter pills are 1.34 mg or 2.65 mg..

So the small pills would have to be a 54 pound shih tzu for a 'normal' dose or a maximum HIGH dose for a 27 lb dog twice a day. That's a pretty big shih tzu! (or you're over dosing).

 
  It's a good idea to ask your vet what they recommend; the derm vet I take Jessie to said she can take two Tavist twice a day; that's for a 62lb. dog.

ORIGINAL: calliecritturs

Shelly, you're right -- nothing 'cures' an allergy.  I'm allergic to fresh basil and I will always BE allergic to fresh basil.  Even if I'm 'desensitized' (like shots) ... it's not a 'cure' ... it's making you 'less' sensitive.

The thing with antihistamines is you have to give it consistently in order for the body to process the histamines as they come in.  So giving it daily thru the season or as long as needed is important.

Just FYI -- ziggynemo -- if you are givng a WHOLE Tavist to a shih tzu??  wow --

The dose for Tavist/clemastine is 0.025 to 0.05 mg/lb -- and the over the counter pills are 1.34 mg or 2.65 mg.. 

So the small pills would have to be  a 54 pound shih tzu for a 'normal' dose or a maximum HIGH dose for a 27 lb dog twice a day.  That's a pretty big shih tzu!  (or you're over dosing).

I honestly can't stress enough -- when you begin giving them most any antihistamine, they will be sleepy, but it's a side effect that goes away after a few days.

But yes, typically it will make them sleepy (at first) but it will always make them thirsty and do *not* deny them water.  That's really important or you can damage the kidneys.

Giving it once a day in a high dose doesn't 'help' because the drug lasts 12 hours in the body.   

 
I am giving the dosage my derm vet told me to give him. I double checked with her AND my regular vet today when I had to take my other dog in for a check and this is the dosage they recommend. My tzu weighs 17 lbs.

  " I was just wondering if the more the dogs take the antihistamines, does that mean they will require more of them or higher doses? "
     Never heard of that happening so I doubt it. You could ask your vet about it.
 
 The only side effects I've heard of are drowsiness, constipation, hyperactivity, dry mouth, and lack of appetite. Jessie has tried several antihistamines and didn't seem to have side effects from any of them except for Doxepin; when we stopped giving it to her she was a little hyper the next day. I have never heard of or read about dogs having withdrawal symptoms when an antihistamine is stopped.
 
    "Also, I am still thinking of getting him allergy tested, but am waiting for his current infection to be gone first."
 
    Have you asked Callie or Angel(Forpaws) about some nutritional supplements to try? Have you tried topical therapies such as bathing with a shampoo made for itchy dogs like Nova Pearls followed with a soothing conditioner? Is your dog getting a meat based diet to give his immune system the help it needs to cope with allergies? Are you trying to control the amount of pollen your dog is exposed to by vacuuming the carpets and furniture every few days and washing his bedding frequently? There are many things you should try first; I did and unfortunately it wasn't enough for Jessie, but she tested in the thousands on the blood test for several allergens; 150 or above is significant; many dogs can be helped by trying the things I suggested. Cathy and Kim (Cakana and Terrierlover) know some very good shampoos and conditioners and Callie and Forpaws know some good supplements and skin treatments; you should try them to see if they help your dog. I'm not telling you not to try immunotherapy but am telling you there's other options to try first that can help.

Since I can't get an 'answer' verbally from a dog the only thing I can answer with is human viewpoint (not being sarcastic -- I really meant that) -- typically the body doesn't get 'used to' Benedryl ... usually either it works or not.  Some anthistamines the body can get used to ... a friend of mine took Tavist for a couple of years and thot it was great and then suddenly it just stopped doing anything for her. 
 
But you can't take 'more' and have it do anything -- you just have to move on.
 
And just watch your doses carefully -- in honesty, I wouldn't give *my* dog the 'max' dose day after day.   I've been there done that ... and it DOES weaken the kidneys at max strength.  It might help sthe symptoms ... but that's where long term 'side effects' can happen.  Given at the lower doses the body seems to handle them better.  Again ... that's just MY experience with my dog. 
 
Nothing 'bad' about anyone's vet but often vets are more interested in TODAY than later.  They will give you whatever it takes to relieve the symptoms today ... and not really consider strongly 'tomorrow'.  Not all vets do that ... but ...
 
And you really aren't getting the true picture only giving it once a day.  Because clemastine is a 12 hour drug.  And a lot of how an anti-histamine works is helping the body cope with the histamines (allergens) in the body NOW.

ziggynemo -- just fwiw - I didn't pluck those figures out of thin air.  "Pill Book Guide to Medication for Your Dog and Cat" (Dell, reference).  But a vet can and will exceed recommended doses when they feel it is warranted ... but as I said above .. that's where I get worried about longer term side effects becoming more pronounced is all.  Just from experience.