When you are given a prescription for a medication for your pet, it means that your veterinarian has made a decision that the medication is recommended or necessary to treat your pet's health problem. Many prescription drugs are only effective for specific problems, and may actually be harmful to your pet if used without that critical veterinary examination and diagnosis. Having these drugs available as prescription-only medications ensures that they are used appropriately.
It is unethical, and in most states, unlawful, for a veterinarian to write a prescription or dispense a prescription drug outside a Veterinarian-Client-Patient Relationship (VCPR). For more information about the VCPR, including a definition, see Section III of the AVMA's Principles of Veterinary Medical Ethics. For a simpler explanation of the VCPR, read our "Frequently Asked Questions by Pet Owners about the Veterinarian-Client-Patient Relationship."
In order to maintain a VCPR, your veterinarian must see your pet regularly – how regularly they need to see your pet depends on your pet's health. If your pet is on a prescription medicine, your veterinarian may need to reexamine your pet, check blood work, or perform other tests to monitor your pet's response to treatment and determine if the medication needs to be changed. For example, a dog being treated for hypothyroidism needs to be reevaluated regularly to make sure the dosage is having the effect it needs to have.
You have several options when your pet needs a prescription medication: you can get it from your veterinarian if they keep it in stock; your veterinarian can write (or call in) a prescription to a local pharmacy that stocks the medication; or your veterinarian can provide a prescription so you can get the medication from an online pharmacy.
There are several reasons you should consider getting your pet's medications from your veterinarian: if your veterinarian has the medication in stock, you immediately have it and you don't have to wait to get it from a pharmacy; your veterinarian or a veterinary technician can answer your questions, provide you with instructions for use, and maybe even demonstrate how to give your pet the medication; and if you order from a pharmacy and the medication isn't properly shipped (for example, it is allowed to get too hot or too cold) or isn't properly packaged, it could be ineffective or damaged and unusable; whereas if you get it from your veterinarian, you know it has been properly handled until it reaches you and they can inform you how to make sure you handle the medication properly.
Prescriptions and Pharmacies FAQ
Purchasing Pet Drugs Online: Buyer Beware (FDA)