Below are answers to the most common questions the AVMA receives about veterinary prescriptions and pharmacies.
Q: Why do I need a prescription?
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.