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How would WE know if a medication prescribed for our Companion turns out to be ineffective or dangerous? Well, this is HOW IT WORKS:

FDA = US Food and Drug Administration (approves the drugs for the manufacturers.  The veterinarian is the CUSTOMER of the manufacturer.  Companion Animals are the patients of the vets and we humans are the clients of the vets, AKA "the Consumer".

CVM = Center for Veterinary Medicine

These two government agencies work together (in cooperation) to oversee the drugs, feed, devices and various other issues that are used on/in animals - companions and non-companion animals.

As I understand it, the CVM receives the reports of adverse reactions - officially referred to as "Adverse Drug Experiences" (ADEs).  Then, if there seems to be many fairly serious "Experiences" or A LOT of them, the FDA has the drug manufacturer issue a "Dear Doctors Letter" to warn them of the problem and inform them of the UPDATED information.  This is intended to PREVENT further injury/death of companion animals.  In some instances the drug is recalled.

Sometimes the FDA issues a "Warning Letter" to drug manufacturers.

One Division of the CVM  is The FDA / CVM Office of Surveillance and Compliance (excerpted and edited with highlights/bold type/italics, for emphasis)

"Even though a new animal drug product is carefully tested before it is marketed, wider use of the product may disclose problems not evident during the pre-marketing research. Therefore, the assessment of the safety of a new drug is a continuing process that takes place throughout the development and marketing of a drug. Post-marketing surveillance is the process for assessing drug safety."

"The CVM's Office of Surveillance and Compliance (OS&C), in cooperation with the FDA Field Offices, monitors marketed animal drugs, food additives, and veterinary devices to assure their safety and effectiveness. This regulatory responsibility is carried out by scientists, investigators, and analysts around the country."

"Functions among the OS&C Divisions are varied, yet closely related. One Division’s function is the overseeing of medicated animal feeds. Another involves monitoring drugs used in food and non-food animals, and providing scientific expertise for legal cases."

Additional functions of the OS&C include:

  • Monitors approved veterinary drugs and food additives to assure their continued safety and effectiveness.
  • Monitors marketed unapproved veterinary drugs and veterinary devices.
  • Reviews product labels and provides assessments of their status.
  • Withdraws drugs and food additives from the market when conditions warrant removal, based on scientific fact concerning a lack of safety and/or effectiveness
  • Continuously monitors and evaluates reports of adverse drug experiences for animal safety and public health issues. Withdrawal of an approved drug may be recommended if it is determined to be unsafe or ineffective.



Center for Veterinary Medicine (CVM)


 There's a Monthly Newsletter published, and this one has an interesting article about Adverse Drug Reactions:

 FDA VETERINARIAN MARCH/APRIL 2004  Vol. XIX, No. II (pages 8 & 9 excerpted and edited with highlights/bold type/italics, for emphasis)

Adverse Drug Experience Reports Lead to Label Changes, Other Actions for Safer Animal Drugs

More than 2,000 reports on adverse experiences from drugs reach the Center for Veterinary Medicine each month. Analyzing the information is a substantial task, but the result is safer animal drugs.

About 99% of all the Adverse Drug Experience (ADE) reports the Center receives come from animal drug manufacturers, who are required to pass along to CVM such reports received from veterinarians and others who use the products. As information is received, CVM’s staff continually works to sort it all out. [**NOTE: The "majority of calls" to the CVM hotline reporting adverse reactions are from dog OWNERS -- see Dr. Hampshire's quote below from the AVMA Journal, January 2004]

Animal drug regulations require drug manufacturers to report any serious adverse reaction within 15 days of the event. More routine adverse events are reported at scheduled times—semiannually during a drug’s first two years on the market following approval, then annually after that.

When the reports reach CVM, the staff evaluates the adverse events for seriousness and frequency. The staff uses a variation of a system used to evaluate adverse experience reports about human drugs. The reviewer uses a scoring system to determine the likelihood that the drug was positively linked, probably linked, or possibly linked to the adverse event.

The reviewer also notes when the information available was not enough to draw a conclusion, and if the drug was used for an indication not on the label. When the review indicates a slight to a strong link between the adverse event and the drug, information from the ADE is entered into a database that is available on CVM’s website for public review. The database is updated monthly.


CVM is likely to ask the drug sponsor to make labeling changes or take other steps, such as sending a “Dear Doctor” letter to its client-veterinarians, if certain trigger points appear in the database. (To see “Dear Doctor” letters, go to CVM’s website and search using that term.)

For instance, if certain adverse experience signs show up frequently in the database, and the causality scores are in the possible-to-probable range, CVM officials are likely to contact the drug sponsor about label changes or other steps.

Also, if the scores are in the definite range and the adverse experience is severe, such as death, CVM officials are likely to ask the manufacturer to take some steps, even though the adverse events are not frequent.

Sometimes the ADE finding leads the company to revise the label—for instance to add safety warnings or to highlight information already there. And often the company will send out the “Dear Doctor” letter highlighting the change for veterinarians.


The Center’s recent work to revise labels on some relatively new pain relief drugs for dogs demonstrates how the ADE process works. In the past few years, CVM has approved several non-steroidal anti-inflammatory drugs (NSAID) for use in dogs. NSAIDs are not new. They have been available for human use for several years, and examples include many over-the-counter products such as aspirin, acetaminophen, ibuprofen, and naproxen.

NSAIDs are effective in canines for the relief of pain associated with osteoarthritis or for treating postoperative pain. Some older NSAID products FDA approved for use in animals include etodolac, carprofen, and deracoxib. Newer ones include meloxicam and tepoxalin approved for use in dogs.

Recently approved NSAIDS typically are what scientists call cox-selective agents. The drugs are believed to be safer than earlier NSAIDs, but they are not completely safe.

Information in CVM’s ADE database indicates that the most common adverse experiences that have been reported following the use of an NSAID in a dog are vomiting, anorexia, depression, and diarrhea. Less commonly reported but more serious ADEs include gastric ulceration, intestinal ulceration, renal failure, hepatic failure, and even death.

The ADE reports on NSAIDs have led to revised labels. For instance, CVM has required manufacturers to add a label section that specifically addresses these “post-approval experiences.” About 99% of all the Adverse Drug Experience (ADE) reports the Center receives come from animal drug manufacturers, who are required to pass along to CVM such reports received from veterinarians and others who use the products. [**NOTE: The "majority of calls" to the CVM hotline reporting adverse reactions are from dog OWNERS -- see Dr. Hampshire's quote below from the AVMA Journal, January 2004]

Beyond Label Changes

Beyond official requests for label changes, CVM staff can use the ADE reports in other, non-regulatory ways to make veterinary medicine safer for animals. NSAIDs provide a good example of how that works, too.

The analysis of the ADEs for NSAIDs led CVM to recommend that veterinarians:

• Pay attention to dosage, and dose strictly according to the patient’s body weight. Some NSAID products have two dose levels, one for long-term use for osteoarthritis patients, and another higher dose for short-term post-operative pain. Even better than dosing based strictly according to body weight, veterinarians can determine the dose for each dog individually by titrating the dose to desired effect.

• Screen their patients for renal and hepatic disease and monitor patients during treatment. NSAIDs can be nephrotoxic and hepatotoxic.

• Optimize surgical patients’ hydration status by providing parenteral fluids. Dehydrated patients should not receive NSAIDs.

• Allow adequate time for their patients to “wash-out,” or eliminate from their systems, previous NSAID or corticosteroid treatments before a new NSAID treatment is administered. The length of time that constitutes “adequate” has yet to be firmly determined, but product manufacturers can help veterinarians determine current recommendations.

• Read the NSAIDs label and understand the risks presented by the use of the NSAID products. Veterinarians should also make it a point to communicate the risk information to the pet owners. Risk information is often available on the client information sheets that come with the NSAID product. The veterinarian should be sure that the client receives any information sheet that accompanies the product.See: "INFORMED CONSENT"

Consumer Concerns

Not all the information CVM reviews comes from the formal ADE reporting system. Some information comes directly from consumers. Although the total number of ADEs from consumers probably equals less than 1% of all the reports the Center receives, the reports from consumers often provide valuable information about how veterinarians are keeping their clients informed. [**NOTE: The "majority of calls" to the CVM hotline reporting adverse reactions are from dog OWNERS -- see Dr. Hampshire's quote below from the AVMA Journal, January 2004]

The consumer information typically comes to CVM via the adverse event telephone “hotline.” CVM originally established the hotline for use by veterinarians, but the majority of calls come from consumers who found the phone number on CVM’s website.

CVM officials recently conducted an analysis of the past two years of calls to the hotline, and the review indicated clearly that consumers often will become heavily involved with the treatment their pets have been getting and that they use the Internet to find out more about the drugs their pets get.

In addition, the analysis showed that consumers are willing to tell CVM if they believe they did not get all the information they should have from their veterinarians about the drugs prescribed for their pets.

Victoria Hampshire, V.M.D., the adverse drug events coordinator in CVM’s Office of Surveillance and Compliance, recently wrote in an article for the Journal of American Veterinary Medicine Association about the analysis. Dr. Hampshire said that pet owners are calling the hotline to report that their veterinarians did not provide the label information and client information sheets that the owners later found on CVM’s website.

According to Dr. Hampshire, CVM considers the drug label as the first source of information for veterinarians about the drug. The label is the result of extensive, science-based, regulatory review. The label describes safety and efficacy factors about the drug, and it describes the animals for which its use is intended.

Besides presenting information on the label, manufacturers also can use a client information sheet, which is information that animal owners should have beyond what is on the label. Sometimes the manufacturer decides that a client information sheet is needed, and sometimes CVM decides one is needed and requests the manufacturer to develop it. The client information sheet can be as important as the drug’s label to ensure the safe and proper use of the drug.

In the article, Dr. Hampshire also advised veterinarians to:

• Give their customers any client information sheets that come with the drug.

• Read the labels to identify contraindications, safety information, and warnings about what animals would not be good candidates for medication.

• Make sure that labels have not changed. A large stock of a drug could mean a long time between reorders. The label could change during that time, but the veterinarian would not be aware of the change.

(Much of the information generated for this article was provided by Thomas J. Moskal, D.V.M., Veterinary Medical Officer with the Division of Surveillance.)


** "The CVM [Center for Veterinary Medicine] established the hotline, (888) FDA-VETS, in 1996 to receive calls about adverse experiences to approved animal drugs."       "We expected many of these reports to come from practicing veterinarians, but our review indicates that a majority of the calls in the past few years have come from consumers, particularly dog owners who find our link on the Internet." --Dr. Victoria Hampshire

from the Journal of the American Veterinary Medical Assoc. (AVMA) FDA Surveillance News  January 15, 2004 [excerpt]


ã Copyright 1995 Helen L. McKinnon All Rights Reserved

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