Prescriptions and Pharmacies: For Pet Owners (FAQ)

Below are answers to the most common questions we receive at the AVMA about veterinary prescriptions and pharmacies.

Q: Why do I need a prescription?

A: 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.

Let's take heartworm preventives as an example. Heartworm preventives are labeled as "prescription-only" because it's critical that your veterinarian makes sure the medication is the right one based on your pet's health status. The preventives target the infective larvae as they are migrating through the tissue prior to reaching the bloodstream and developing to adult heartworms. If your dog (or cat) has heartworms, giving a preventive medication will not effectively treat the disease because the preventives don't readily kill adult heartworms. In some cases, administering preventives to heartworm positive dogs can cause a rapid kill of circulating microfilariae, leading to a life-threatening anaphylactic reaction.

There are drugs, called "over the counter" (OTC) drugs, that don't require prescriptions. Drugs can be bought OTC when the Food and Drug Administration (FDA) determines that the directions for the drug's use aren't overly complicated and are adequate for the public to follow. In some cases, such as the common headache medications for people, the OTC version is just a weaker strength than the prescription form. However, in many cases, a medication is only available with a prescription for the reasons we mention above.

Q: What's the difference between the brand name, trade name and generic name of a medication?

A: Brand names and trade names are also called proprietary names, and are just what they sound like – they are the trademarked names you recognize on the shelves and see in advertisements. The generic name, on the other hand, is the nonproprietary name of the drug and is the same for all versions (brand-name and otherwise) of that drug. For example, take ibuprofen: there are several brand names for the drug, including Motrin® and Advil®, but the generic name of the drug is ibuprofen. If you were to buy the brand/trade name of the drug (for yourself, not your pet), you'd purchase Motrin® or Advil®, but if you were to buy the generic version, it would just be labeled "ibuprofen."

Q: Is there a difference between the brand name version and the generic version of a medication?

A: For the most part, no. The United States Pharmacopeia (USP) sets the standards for the quality, purity, strength and consistency of all prescription and OTC medications in the U.S. – the goal is to make sure that the product you purchase meets these standards. If you look closely at the drug labels, you'll see "USP" printed after the drug name in the ingredients list – and sometimes it's printed clearly on the front label of the bottle/box. Based on USP standards, for example, generic ibuprofen is the same drug as the brand name-versions of ibuprofen (of the same strength) as far as the quality, purity, and consistency are concerned.

However, we have heard some anecdotal and unconfirmed reports of pets that had been receiving a brand name medication, but did not do as well when given a generic version of the same medication. Although all USP versions of a drug meet the purity standards for that drug, all of the ingredients and the processes involved in making the trade name versions are often protected by patent or other intellectual property laws, and there may be differences in the minor ingredients that could produce slightly different results between the versions, while still providing the main drug that meets USP standards. Think of it as following a recipe – even if you have the same ingredients and follow the instructions, the end result might vary a little bit. This is not a common problem with medications, and is often resolved by switching back to the effective version of the medication.

Q: Why are some spot-on flea and tick preventive medications only available through my veterinarian?

A: Some manufacturers have decided to sell their products only through veterinarians so that the veterinarian and pet owner can discuss the situation and work together to determine the best flea and tick treatment for that pet. It's not that the product is "prescription-only" – it's that the manufacturer believes the product should only be sold through veterinarians. In addition, it seems more likely that the product will be used properly (for example, a cat won't be treated with a product labeled only for use in dogs) if the veterinarian is supplying the medication and is counseling the pet owner on the proper use of the medication.

If the spot-on flea and tick product is also labeled for heartworm prevention, it is only available through your veterinarian for the reason we previously described – it is critical that your veterinarian checks for a heartworm infection before your pet is given a heartworm preventive medication.

Q: My veterinarian gave me a prescription for a pain reliever for my pet. Why can't I just buy one of the over-the-counter pain relievers at my local drug store?

A: Don't do it! Although these products are approved for use in people, many of them are not safe for pets. For example, acetaminophen (Tylenol® is the most common example) can cause severe illness, and even death, in pets. Talk to your veterinarian before you give ANY medication to your pet.

Q: Where can I get my pet's prescriptions filled?

A: 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.

Q: Can I get my pet's prescription medications from Canada?

A: No. Drugs from Canada are not approved by the federal government for use in the United States. It is illegal for you to get medications shipped from Canada for yourself or your pet.

Q: The pharmacy told me I don't need a prescription for a medication. Is that true?

A: For some OTC medications, it is true. However, if your veterinarian tells you that you need a prescription for the medication but the pharmacy tells you that you don't need it, this might indicate that the pharmacy's staff is either confused or misinformed, or the pharmacy's ethics and standards are questionable. If this happens, talk to your veterinarian, contact the state board of pharmacy, or contact the U.S. Food and Drug Administration Center for Veterinary Medicine (FDA CVM)

Q: Why should I consider getting my pet's medications from my veterinarian?

A: 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;
  • 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.

Q: If I choose to get my pet's prescriptions filled elsewhere, can my veterinarian refuse to give me a prescription?

A: Your veterinarian might strongly recommend that you get the medication directly from them, but some states actually require veterinarians to write prescriptions for clients to have filled elsewhere if requested by the client. Some states do not require this of veterinarians.

There are certainly situations where it is in your pet's best interest to get the medication directly from your veterinarian, and we encourage you to discuss your options with your veterinarian. The AVMA's Principles of Veterinary Medical Ethics recommends that veterinarians comply with their client's wishes and provide written prescriptions if the client prefers having the prescription filled elsewhere.

Q: Can my veterinarian charge me a fee for writing a prescription for my pet?

A: There is no federal law preventing your veterinarian from charging you a fee for their services and time invested in writing a prescription. Some veterinarians charge a nominal fee for writing prescriptions, but others don't. Individual states might have specific guidance for veterinarians on prescription fees.

Q: My veterinarian is telling me that I have to bring my pet in for an examination before they'll write a prescription or authorize a refill. Why?

A: According to the AVMA Principles of Veterinary Medical Ethics, 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.

Q: If I choose to get my pet's prescription filled elsewhere, will my veterinarian refuse to see my pet anymore?

A: That's not likely. We encourage you to talk to your veterinarian about your concerns and discuss what's best for your pet.

Q: Why do some medications cost more from my veterinarian than from an online store?

A: Online pharmacies may buy larger volumes of the medications at a time, so they may get bulk pricing that might be lower (or much lower) than your veterinarian pays - so, even with a markup, some medications from an online source are being sold to you for less than your veterinarian pays to get the medication. Anybody who keeps medications in stock has to mark up the prices above what they paid because of the overhead costs involved in keeping those medications on the shelf and the losses if the medication expires and has to be discarded.

Q: What are the risks of ordering from an online pharmacy?

A: The amount of risk depends on the quality of the pharmacy. Human error is a risk with any source, but the risk is minimal if the proper procedures are in place.

When you order from an online pharmacy, the product must be shipped to you. If 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.

If there is a problem with the medication received from an online pharmacy, there might be a period of time when your pet isn't getting its medication while you wait for the replacement medication to arrive.

Q: How do I know the pharmacy is trustworthy?

A: Prior experience with a pharmacy is a good indication – ask your veterinarian if there is a pharmacy they recommend. You can also inquire with the state board of pharmacy to determine whether a pharmacy is licensed within the state and the status of the pharmacy's license.

In addition, accreditation by independent bodies can give you more information about an online pharmacy. Two examples of third-party accreditation include the National Association Boards of Pharmacy Vet-VIPPS program and, for compounding pharmacies, the Pharmacy Compounding Accreditation Board. (Your prescription might be called in to a compounding pharmacy if your pet needs a medication tailored just for him or her – an example would be a flavored liquid medication for a cat who otherwise won't take the medication. It is NOT legal, however, to have a compounding pharmacy make a "cheaper" version of an identical product that has been approved by the FDA.)

Q: How will I know if there are problems with the medications I get from a pharmacy?

A: First of all, talk to your veterinarian about the signs of a problem with the medication. Make sure you know what to look for, and what to do if you see it. Don't hesitate to contact your veterinarian if you are concerned that your pet is having a problem with or a reaction to the medication.

If you receive a shipped medication and the package is damaged or it appears to have been allowed to get too hot or too cold, contact the pharmacy immediately and notify them of the problem. If you are not sure if the medication is safe to use in that condition, contact your veterinarian.

If you have concerns or complaints about a pharmacy's practices or the quality of its products, you can report the pharmacy to your state board of pharmacy.

Q: My veterinarian said that my pet needs to get a different dose than what the drug package insert says. Is this legal?

A: If your veterinarian thinks the labeled dose isn't right for your pet but a different dose is what your pet needs, this is a federally regulated activity called "extralabel drug use." Basically, if the medication is used in any other way than the label dictates, this is extralabel use, and it is legal as long as your veterinarian follows the regulations. Your veterinarian can also prescribe a human medication for your pet, and this is also considered extralabel use.

Please note that we're only talking about extralabel drug use in pets here. Extralabel use is legal in food-producing animals, but the rules are much more strict.

This FAQ was produced by the AVMA Scientific Activities and Communications Divisions, with assistance from the Council on Biologic and Therapeutic Agents and the Clinical Practitioners Advisory Committee.

Additional resources:

US Food and Drug Administration (FDA)


This information has been prepared as a service by the American Veterinary Medical Association. Redistribution is acceptable, but the document's original content and format must be maintained, and its source must be prominently identified. Please contact Dr. Kimberly May (800.248.2862, ext 6667) or Dr. Lynne White-Shim (800.248.2862, ext 6784) with questions or comments.