I don't buy any prescription medications from an online pharmacy without a prescription from either of my Vets. My one Vet has basically phases out his pharmacy stop, except for what he might need immediately. They call your prescription into some online pharmacy who calls you to tell you that your prescription is ready, but they will never quote you a price. When I contact them, I find that their price is higher than the regular online pharmacies I use, and which I have found to be pretty reputable.
These are the online pharmacies I have used, and they always have to get the prescription authorized from the Vet. That's just the way it is supposed to work with a legitimate online pharmacy.
I shop around for best prices for the prescription meds. I typically use the following online pharmacies:
www.petcarerx.com
www.discountpetdrugs.com
www.entirelypets.com
and if you need a compounded medication, I use:
www.islandpharmacy.com (I get cyclosporine 2% drops in oil)
I am sure there are many other pet pharmacies out there, but I have used all of these and have had no problems with them, and I have not had any complaints from my Vets about them.
Both of my dogs are on long-term and probably lifetime medications, so I need to get my products as inexpensively as possible. The brand is typically the same, so I just check to see whose price is lowest and I go from there. My Vet(s) understand my need to save money on long term maintenance medications.
But always go through your Vet. Your Vet knows what is the best medication for your pet. Trust the Vet. If it is a one-time medication, probably getting through your Vet is best. If it is medication that you will need refills on, talk to you Vet about it. Maybe do some searches on the exact medication and which online pharmacy it is, and see if you Vet will authorize you to use them.
I know my new Vet wants to make sure that the online pharmacies are licensed to dispense in California. He's a good man. I appreciate that he is willing to work with me to save me money on my long term maintenance meds.