Prior to the 1990s, treating dogs and other companion animals for pain was rare, if not unheard of, in most veterinary practices. Scientists and veterinarians simply did not have research data confirming that animals experience pain, whether post-operatively or as a result of an acute injury or chronic condition or disease. At least they didn’t believe that pets experience pain that needed to be treated as it would in human patients. This is somewhat understandable, since, by design and instinct, dogs hide pain.

In the wild, an animal that shows signs of pain or distress is vulnerable to attack by others of its species or by predators. Our domesticated pets have retained the instinct to act as though nothing is wrong, even when something might be very wrong, and some researchers believe that animals in pain self-limit their own activity, which helps speed the healing process. For much of the history of the domesticated dog as house pet and companion, humans largely bought into the canine’s failure to show pain.

In the past decade, however, research has confirmed that dogs do experience pain. Subjective measurements are based largely on observations of behavior, such as shivering, panting, stiff movement, lying very still or in an unusual position, or seeking a place to be away from people or other animals. A dog in pain might also have dilated pupils, or may refuse food. Objective measurements, such as an increase in heart or respiratory rate or a rise in blood pressure, are more reliable indicators of pain.

Many breeders and pet owners believed prior to getting confirmation from researchers that, in some instances, their dogs needed relief from discomfort or pain, and using human medications such as baby aspirin was not uncommon. It is crucial to note, however, that giving aspirin to cats may be harmful or even lethal.

But today many pain relief medications are formulated specifically for pets, and veterinarians work diligently both to manage existing pain and to anticipate and prevent pain in dogs and other companion animals. Veterinarians today understand that pain management not only has immediate consequences for companion animals, including shortening of recovery time, but that by reducing stress on the animal its life may be prolonged and its quality of life is greatly enhanced.

Researchers also discovered that, on occasion, behavioral problems in companion animals, including aggression, were directly related to pain, and that pain management can help diminish unwanted behaviors.

Today’s pain relievers are administered as injections, oral medications and sometimes even as pain patches, just like humans use. Dogs that have no sign of kidney or liver problems are now routinely given nonsteroidal anti-inflammatory drugs for chronic pain associated with conditions such as arthritis. These drugs treat musculoskeletal pain, but unfortunately can cause damage to the stomach, liver and kidneys in some dogs, just as they can in humans. Although at one time it was believed that some specific breeds were more sensitive to the negative effects than others, a 2008 study conducted by the Morris Animal Foundation found no evidence that particular breeds are at higher risk than others.

Dogs recovering from injury or surgery or experiencing chronic pain from illness can now get relief from pain medications. Photo © Can Stock Photo Inc./monkeybusiness

Pets in severe pain from injury or even illnesses like cancer may be given narcotic pain killers. Many different types of analgesics exist for long- and short-term pain. Vets may prescribe muscle relaxers, sedatives and even products with antidepressant properties to help manage pain in pets. Topical preparations may be used for surface wounds.

Of course, as with any medications, these pain relievers have side effects, and their use should be discussed with a veterinarian. And because medications can have a much different effect on a dog than a human, before using any medication, including over-the-counter formulations, a veterinarian should be consulted.

Even with enhanced understanding provided by years of research, treating pain in dogs is still not easy, in part because veterinarians simply don’t get feedback from their patients the way human physicians do. In an effort to further progress in the field of pain management in dogs, the Morris Animal Foundation recently provided funding for Lesley Smith, D.V.M., a board-certified veterinary anesthesiologist at the University of Wisconsin, to study more effective methods for treating postoperative pain in dogs.

Smith’s study looked at a drug called hydromorphone, an opiate drug, given one time via an injection under the skin and that lasts three days. Smith and her team “reformulated hydromorphone into a lipid-based vesicle that slowly releases the drug to deliver a steady stream of pain relief.” She likened the action of the drug to what happens when a hospitalized human patient with an IV has a button to push that administers more pain medication. Because our pets can’t push a button for themselves, the drug itself is now formulated to provide periodic bursts of pain relief.

An added advantage of the new formulation, now known as DPPC-C hydromorphone, is that it doesn’t cause “unexpected side effects.” Although this drug is not currently available for pain management in dogs, it is a positive step toward developing “long-acting” pain medications.

Of course, there are methods for helping to reduce pain in our pets other than drugs. Reducing a pet’s weight and increasing or decreasing exercise can help with musculoskeletal pain. Changes in floor surfaces and raising water and food dishes can make it easier for a pet in pain to maneuver through his daily life. Soft bedding can ease pain from chronic illness or when a dog is recovering from injury.

Alternative therapies such as chiropractic care, acupuncture and other rehabilitative therapies may help in some instances, and numerous dietary supplements on the market appear to help relieve some types of pain. Often a combination of medication and alternative therapies is most effective. Perhaps most importantly, thoughtful care and attention from owners and caregivers will help canine patients suffering from pain.

The American Animal Hospital Association website //link “American Animal Hospital Association” to offers comprehensive guidelines for pain management for dogs and cats.

The following sources were used in the development of this article:

The American Animal Hospital Association and the American Association of Feline Practitioners “AAHA/AAFP Pain Management Guidelines,” Journal of the American Animal Hospital Association, September/October 2007, Vol. 43.

The Journal of the American Veterinary Medical Association online:

Morris Animal Foundation Animal News, May 2012, Vol. 12 Issue 2.

Morris Animal Foundation, “Incidence and Breed-Related Risk Factors for NSAID-Associated Adverse Events in Dogs,”