Yikes! Would you please direct to your sources so I can look into this? Thanks.
You won't find any, or at least very few.
A few years ago there were some cases of flea and heartworm meds that were packaged similarly to those sold at the vet but were not the same or were expired. I don't know if that ever got corrected, but I'm guessing the FDA did something to make sure that was taken care of.
In reality most reputable online pet pharmacies are just fine. All of the vets I've worked with over the past 10 years or more have supported the use of them (I used PetCareRX) for my dog's thyroid medication, heartworm meds, and some others. For obvious reasons, I was not able to use them for insulin for my diabetic dogs.
There are some questionable veterinary offices out there who want to keep all the money they make off expensive medications for themselves. Those are the ones I'd be wary of...for they are more concerned about their profit than they are about your ability to continually care for your pet.
Too many people will decide to euthanize a pet with manageable illnesses because of the cost of medications (i.e. diabetic dogs). Concerned veterinarians are learning that enabling the owners to obtain medications in cost effective ways keeps animals alive and healthy longer.
Talk with your vet about different options, talk to a holistic vet about inexpensive supplements (for arthritis, glucosamine and chondroitin are well accepted, and you can find good quality supplements at petsmart or petco).
And see if you can get that prescription at
walmart or a closer pharmacy and get that card!!
edited to add the FDA information about online pet pharmacies:
http://www.fda.gov/animalveterinary/resourcesforyou/animalhealthliteracy/ucm203000.htm