We all have taken a drug of one kind or another. Drugs have been used for decades to treat humans and animals alike. We might take it for granted that we have access to so many different drugs to help with all sorts of ailments. If we have a headache we can take ibuprofen, or aspirin to stop the pain. But if we have strep throat our doctor might prescribe an antibiotic to rid us of the bacteria. Both are considered drugs, but one is considered an over the counter drug (OTC) and the other is considered a prescription drug. The same is true in veterinary medicine. Dewormers are considered OTC, while phenylbutazone is considered a prescription drug. So what makes one OTC and the other a prescription? How do you get a prescription for your horse? What’s the difference between regular prescription drugs and generic prescription drugs? These questions and a few more will be answered in this article.

First, let’s clarify what the Food and Drug Administration (FDA) considers a drug. The FDA definition is: A drug is a substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease. (The FDA has the regulatory power to approve and monitor all the drugs made and sold in the US, both human and veterinary.)

If we look again at the FDA definitions, the difference between prescription drugs and OTC is that doctors issue prescriptions for prescribed drugs, are sold through pharmacies, and the FDA has to approve these drugs for its intended use. However OTC drugs are not prescribed, can be bought off-the-shelf, but are still monitored and approved by the FDA. In veterinary medicine, veterinarians also prescribe the drugs, and in addition routinely act as the pharmacy. Another difference is that prescription drugs may be more dangerous to be given if not done so properly and have a very narrow range of safety for administration.

We can also break down prescription drugs into different classifications. Most prescription drugs that you may have for your horse will be labeled with an “Rx” symbol on the label. Other classes of prescription drugs are classified as “Scheduled” and these are considered controlled substance.

While the FDA approves these drugs these controlled substances are monitored by the Drug Enforcement Agency (DEA). Controlled substances are drugs that have the potential of some very severe side effects, have a high potential for abuse and with potentially severe psychological or physical dependence. There are Schedule I to Schedule V drugs, with Schedule I drugs having no medicinal use. Examples are LSD and heroin. In equine veterinary medicine, there are only a few Scheduled drugs that are used. Most are anesthetic drugs (ketamine, and Valium), pain control drugs (morphine and butorphanol), and euthanasia drugs. All controlled substances are kept under tighter security and have additional record keeping to maintain.
The following are some frequently asked questions about prescription drugs and veterinary medicine.

Q: How do I get a prescription for my horse?
A: To prescribe either classes of drugs, a veterinarian must be licensed in the state in which they practice, have a DEA license for Scheduled drugs, and must have a veterinarian-client-patient-relationship (VCPR). A VCPR is defined by the State of Colorado as “The veterinary-client-patient relationship is the basis for veterinary care. To establish such a relationship, the veterinarian should have sufficient knowledge of the patient to understand its current health and render at least a preliminary diagnosis. This would require that the veterinarian is personally acquainted with the patient either through office or home visits.” Rule III, 7. Without any one of the above criteria is a violation of the State Veterinary Practice Act and can be subject to penalty and loss of license.

Q: What is the difference between regular and generic prescription drugs?
A: All prescription drugs go through an approval process and are tested for efficacy and safety for a specific condition and in veterinary medicine either one or several animal species. During the approval process, the drug compound, the formulation and possibly the delivery method is patented. That patent prevents other pharmaceutical companies from copying the drug and selling it on their own. This give the developing pharmaceutical company a chance to get a fair return on their investment into the research and development. Drug patents are not indefinite and after several years depending on the patent, the patent expires and other pharmaceutical companies can produce and develop their own version of the drug. They too need to go through a less intense approval process, but their drug must also be approved. These drugs are considered generic drugs.

Q: Is a compounded drug the same as a generic?
A: The short answer is no. The FDA defines compounding as “In general, compounding is a practice in which a licensed pharmacist, a licensed physician, licensed veterinarian, or, in the case of an outsourcing facility, a person under the supervision of a licensed pharmacist, combines, mixes, or alters ingredients of a drug to create a medication tailored to the needs of an individual patient.” Compounding a drug can be as simple as taking a dose of pills, crushing or grinding them into a powder and adding a flavoring and carrying agent like molasses. Compounded drugs are not considered FDA approved. We prescribe compounded medications on a case by case basis for the needs of the individual animal.