dog allergyPreviously on this site we have an article about why antihistamine are used with dog allergies, and why the are maybe one of the best chemicals to stop the allergy and scratching at its source.

But you need your antihistamine to attach to the histamines created in the dogs body because of the recognized allergen.  IF the antihistamine doesn’t recognize the specific histamines then it will be ineffective or of no use at all.

Some of the common antihistamines we use are:

Benadryl A   (diphenhydramine)

You might remember this as being used a cough medicine for children for years. It use to be the only thing that mothers would give.  It is a brand name

What are the main uses of Benadryl?

treats sneezing; runny nose; itching, watery eyes; hives; rashes; itching;  basically symptoms of allergies and the cold.

It has also been fund that Benadryl suppress coughs, helps with motion sickness, drowsiness can help sick people sleep.

Side effects:  dizziness and drowsiness.

Bad to use if you have

  • glaucoma
  • stomach ulcer;
  • an enlarged prostate or bladder problems
  • hyperthyroidism – an overactive thyroid gland
  • hypertension or any type of heart problems

So it appears that for the side effects that can happen if you have hidden other problems, this has fallen out of favour.


Atarax (hydroxyzine) reduces activity in the central nervous system. It also acts as an antihistamine.

sedative to treat anxiety and tension

used as part of anaesthesia

treat allergic skin reactions such as hives or contact dermatitis.

BAD SIDE effects:   it can cause  tremors, confusion, seizures, or restless muscle movements in your eyes, tongue, jaw, or neck.   Not to be used with a dog that has a seizure disorder, liver disease, or kidney disease.

Tavist  ( clemastine )

this is the first of the recommended drugs that is mainly an anti histamine.

Side effects

While it has the general issues of potential drowsiness it also can cause issues if your dog has:

  • bronchitis, emphysema, or breathing disorders
  • ulcer or obstruction in the stomach
  • glaucoma
  • enlarged prostate /  urination problems.