For stings/etc: Benadryl dosages
Some people use Benadryl for bee or wasp stings or allergic reactions. It's a good emergency antihistimine to have on hand but note it is NOT recommended to use the LIQUID forumula because of alcohol content. The pills generally come in 25mg size so for the average cavalier you would use just under half a tablet. You can easily cut them in two with a knife.
Note the caution about using it with dogs with cardiovascular disease. This could include MVD, so talk to your vet if you have a cavalier with a heart murmur!
HOWEVER: this applies to US and Canada formulations ONLY. Nicki adds this warning:
Benadryl for Dogs or Cats
Benadryl is a brand name for an anti-histamine (diphenhydramine). Although it is considered fairly safe for use in dogs and cats, please be aware that it does have potential adverse side effects. It may interact with other meds that your pet is taking, so do not use it without first consulting your veterinarian. You should also use extreme caution using Benadryl in dogs that have glaucoma, prostatic disease, cardiovascular disease or hyperthyroidism.
Benadryl is quite effective when used in proper dosages.
Good for motion sickness
Can be used as a mild tranquilizer
Good for snake bites
Useful for vaccination reactions
Good for bee stings and insect bites
Be sure to use only the plain Benadryl formula. Giving benadryl with other combination of meds could be fatal, so be sure to read the box.
Liquid Benadryl is too high in alcohol content to be safely used for animals. Please use capsule or pill form.
Dosage every 8 hours
Dogs under 30 lbs and Cats : 10 mg
Dogs 30-50 lbs: 25 mg
Dogs over 50 lbs: 50 mg
*** If you are in the UK or Ireland, please confirm with your vet that giving Benadryl is safe before using this human over the counter medication on your cavalier.
In the United States and Canada, Benadryl products contain the first-generation antihistamine diphenhydramine. Diphenhydramine is used as an allergy treatment in various forms around the world. It is an H1 receptor antagonist. Antagonism is achieved through blocking the effect of histamine more than blocking its production or release. Diphenhydramine inhibits most responses of smooth muscle to histamine and acts as a vasoconstrictor by inhibiting the vasodilator effects of histamine. The antagonism may also produce anticholinergic effects, antiemetic effects, and significant sedative side effects.
In the United Kingdom, Benadryl products contain either the second-generation non-sedating antihistamine acrivastine (marketed as Benadryl Allergy Relief, with a suggested efficacy duration of eight hours) or the non-sedating antihistamine cetirizine (marketed as Benadryl One a Day Relief). Cetirizine is indicated for the relief of symptoms associated with allergy and hives. It is an orally active and selective H1 receptor antagonist.
I can't find anything to indicate if acrivastine and cetirizine are safe for dogs.