Pet Health Information General
Treating Pain in Pets
Amy D. Shojai
When nine-year-old Sophie developed a tumor, Karen Daiter's
first priority was to relieve the shepherd/collie's discomfort.
"She was a very playful dog, extremely good-natured," says
Daiter. "But she stopped playing, and I didn't want her to feel
bad."
"When our pets are in pain, in a way we feel that too," says
Steve Dale, Sophie's upstairs neighbor and daytime caretaker.
"It's more than just frustrating, because you can't do anything
about their pain. And it's your responsibility."
Pain is an unpleasant sensory or emotional experience that
exists in the mind of the one who is experiencing it. Since
animals can't explain their pain, people have long assumed that
pets don't experience pain to the same degree as people. Although
general anesthesia keeps them immobile and oblivious to any pain
during surgery, pets have historically been under-treated for
pain.
"We have never really trained veterinarians to think about
pain associated with disease," says Dr. William Tranquilli,
professor of clinical medicine at the University of Illinois. The
Companion Animal Pain Management Consortium is trying to change
that. Leading the charge are Dr. Tranquilli; Dr. Charles Short
from the Center for the Management of Animal Pain at the
University of Tennessee; Dr. James Gaynor, associate professor of
anesthesiology at Colorado State; and Pfizer Animal Health, a
pharmaceutical company with U.S. corporate headquarters in New
York (www.pfizer.com/ah/index.html).
Advances are driven in part by owners who don't want furry
family members to suffer. Today, veterinarians and owners
recognize that pets do suffer pain just like people do -
they just express it differently.
Understanding Pain
Damaged tissue releases chemicals that sensitize nerve endings.
Response to pain travels through the nervous system up the spinal
cord to the cortex of the brain, where pain registers and
triggers a protective reflex. This "learned avoidance" teaches
pets to thereafter steer clear of the candle flame, for instance.
Pain also prompts a pet to protect or rest an injury so it
heals.
Not all pain is severe or sudden, or requires heavy-duty
analgesics. "Long-acting steroid products given to reduce
inflammation of the skin are a type of pain management," says Dr.
Tranquilli. So are antibiotics that cure a sore throat, while
chronic joint pain typical in older pets can be relieved with a
heat lamp. Allergic pets get temporary relief from cool water,
which is a natural anesthetic for skin, says Dr. Shawn
Messonnier, a holistic veterinarian and author practicing near
Dallas.
Extreme pain, though, prompts a stress response that alters
immune function, interferes with blood clotting and wound healing
and adversely impacts the cardiovascular system. Extreme pain can
permanently alter neural pathways, creating a neurological
"memory" so that pain continues long after the injury has healed.
Because chronic neuropathic pain is extremely difficult to treat
medically, human anesthesiologists prevent this condition by
incorporating a nerve block along with general anesthesia. Pets
can also be given a local anesthetic into the spinal cord to act
as a regional nerve block that prevents the pain message from
ever reaching the brain.
"Recent studies show if we preempt pain by doing medical
therapy before we make the incision, pets don't need as
much post-surgical medication," says Dr. Messonnier. Preemptive
pain therapy also reduces the amount of general anesthetic
required, and alleviates post-surgical side effects. For example,
preemptive pain control in chest surgery promotes easier
postoperative breathing because drawing deep breaths is not as
painful.
But pain management can interfere with other treatment, says
Jennifer Reding, a veterinary technician in charge of
post-surgical pain management at Veterinary Surgical Associates
in San Mateo, California. "You have to be very careful that you
don't overmedicate and suppress vital signs," she says.
"Sometimes pets are so sick that pain management is way down on
the list - first we want to make sure they live."
Recognizing Pain
Dogs tend to be obvious about their discomfort. "They scream at
you," says Reding. When Stephanie Harpham's six-year-old pit
bull, Chaplin, suddenly began crying a lot, she knew to get
immediate help. "I could tell it hurt him to move," she
says.
Rather than hold up an injured leg, or yelp and flinch, cats
in pain tend to hide. Feline pain symptoms can look the same as
fearful behavior. "If a cat can't relax to close her eyes and go
to sleep, she's probably in a lot of pain," says Reding. Acute
pain can also cause severe behavior changes in cats. "Frequently
they crouch and hide, have big eyes, and are nonverbal until you
touch them - and then they absolutely wig out and try to kill
you!"
It's also hard to generalize about pain symptoms - each pet is
different. Two years ago, Reding's Australian shepherd, Gibson,
just didn't act right. "He was a little slow. He's a big chow
hound, and I had to urge him to eat," says Reding. The exam
revealed a potentially life-threatening pyothorax - an infection
in the chest.
Many prey species (birds, hamsters) instinctually hide their
pain, and some dog breeds (pit bulls, terriers, hunting dogs) are
insensitive to pain when working, but that doesn't mean they
don't hurt or aren't injured. Experts suggest that if the same
condition would be painful in a person, then assume it's painful
in the pet.
Managing the Hurt
Drugs can be used to control pain at any point along the nerve
pathway, but pain tolerances vary from pet to pet just as they do
in people. "In humans there is about a five-fold variation in
pain tolerance for the same surgical procedure," says Dr.
Tranquilli. A one-size-fits-all approach won't work.
The most common analgesics are over-the-counter non-steroidal
anti-inflammatory drugs (NSAIDs), i.e., aspirin, Tylenol®,
Advil®, etc. NSAIDs can be very helpful for a variety of
painful conditions, including cancer. "They didn't find Chaplin's
cancer until he was in too much pain to move," says Harpham.
Although prednisone increased his "accidents," she only cared
that it gave him great pain relief. When prednisone stopped
working, the pit bull was given the NSAID piroxicam (a human
drug) that not only relieves pain but also prompts remissions in
some canine bladder cancers. "Piroxicam worked amazingly well,"
says Harpham.
Pets metabolize drugs differently than people, so remember:
Human medicines may be toxic to pets and should never be given
without a veterinarian's approval. Cats in particular are
very sensitive to pain medicine. NSAID drugs for dogs such as
carprofen (Rimadyl®) and meloxicam (Metacam®) can cause
toxicity in cats, says Dr. Susan Little, a feline specialist in
Ottawa, Ontario. Acetaminophin (Tylenol) should never be given to
cats, and even aspirin can be toxic; it should be used very
sparingly and only as prescribed by a veterinarian.
Dr. Little says drugs like oxymorphone and butorphanol work
well in cats to control post-operative pain for elective
procedures such as spays, neuters or dentistry. Ketoprofen, an
anti-inflammatory drug helpful for arthritis relief, is often
used in combination with other pain relievers. For example,
Winky's cancer biopsy was so deep and painful, the cat couldn't
use that foreleg. His owner, Mary Williams, took the Scottish
fold to specialists for treatment, including pain control. "Winky
seemed to rest more comfortably, and he'd move around more on
three legs when he'd had the ketoprofen," she says.
Narcotic pain relievers such as morphine, codeine and
Demerol® are only available by prescription from the
veterinarian. Orthopedic surgeries are quite painful and are
often treated with morphine or a morphine-derivative drug.
Buprenorphine, 25 times more potent than morphine, takes longer
to work, but lasts longer for severe or chronic pain. Pet owners
may be given torbugesic in an oral delivery mixture -
Torb-in-Syrup® - to rub on the pet's gums for absorption
through the mucus membranes.
Codeine is well-absorbed in the dog and cat digestive tract
and provides effective relief for all but the most severe forms
of pain, such as that associated with cancer. Codeine can be
compounded into peanut butter or fish paste for better pet
acceptance. After surgery, drains can deliver continuous pain
relief into the chest and abdominal cavity, the joint, or even
intravenously via a catheter. Chemotherapy and radiation can also
relieve certain kinds of cancer pain.
Fentanyl® (duragesic) is an opioid drug that comes in a
transdermal patch that provides prolonged narcotic relief for
both dogs and cats. Reding says her clinic gives nearly every
painful patient a Fentanyl patch. "It makes a huge difference,
especially in cats," she says. "The patch makes some cats so
happy, they beg to be petted after surgery."
Reding's dog, Gibson, needed a chest tube to clean out the
infection, and she knew that penetrating the chest cavity is very
painful. "Giving him morphine only relieved the pain to a point.
For the first day he didn't want to move or stand up," she says.
A Fentanyl patch began to work after the first 24 hours. "After
three to four days, Gibson was running around like there was
nothing wrong with him," she says. After another few weeks on
antibiotics, Gibson fully recovered.
Alternative Therapies
Dr. Messonnier advocates using conventional drugs integrated
with alternative pain management therapies. Hydrotherapy (water),
massage, magnets, chiropractic and acupuncture are common
options.
Shepherd/collie Sophie rebounded quickly from tumor-removal
surgery, and Daiter consulted with several specialists for ways
to relieve her dog's cancer pain. Therapy included several
conventional pain medications, along with dietary changes,
acupuncture and massage. "Sophie especially liked massage - she
liked to be touched," says Daiter.
Dr. Messonnier agrees that drugs work best for immediate
relief of acute and severe pain, while herbal, homeopathic and
nutritional supplements are most helpful for chronic conditions.
"For a dog with arthritis, I would use a drug like Rimadyl for a
bad day, and use glucosamine and acupuncture for a long-term
approach," he says. Canine disk disease might be treated with a
combination of acupuncture and a homeopathic remedy called
Hypericum (veterinary strength, not over-the-counter) for nerve
injury. He says homeopathic Arnica is helpful for any sort of
trauma or wound, and also recommends a proprietary herbal mixture
called Post Care to control the bruising, swelling and pain
associated with surgery or trauma.
Light therapy also has applications. "My Cornish rex got on
the wrong side of a dog and was bitten on the hock," says Claire
Marsh of New Zealand. With veterinary care, Ren's wound healed
fine, but the four-year-old cat remained lame. X rays showed a
detached ligament with a bone chip. "The vet felt Ren would be
lame for life," says Marsh. Then a friend loaned her a Bioptron
light.
The light, from Bioptron® Light Therapy Systems, emits
linear polarized light that is said to have a biostimulant effect
on living cells that enhances blood circulation, promotes
regeneration and healing of wounds and provides pain relief. For
Ren, the effect was immediate. For the first time in seven weeks,
Ren started chasing the other cat - in the middle of his first
treatment. After 10 days of therapy, although he still slightly
favors that leg, Marsh says, "Ren zooms around the house like his
old self." She plans to have further X rays done to validate his
recovery with the veterinarian. The Bioptron products have been
approved for use as medical devices in Europe and in Canada. Such
products are available in the United States, but are approved for
cosmetic purposes only. For further information, visit
www.hospitalmanagement.net/contractors/rehabilitation/bioptron.
Consult with a veterinarian who practices integrated medicine for
the best options for your pet. [To find such a veterinarian,
visit www.ahvma.org, or call (410) 569-0795.]
Making Choices
In the last weeks of Sophie's life, the elevator in the
building was out, and she contracted her stomach each time she
was carried up or down the stairs. Although the dog remained
eager to meet people, Dale says, "You could tell she was hurting,
but she never lost her dignity." As the end neared, Daiter's
priority for her pet was making sure that Sophie could enjoy the
time she had left. "We used a morphine patch to ease her pain, so
she could be with me and her friends in the building and go out
happy."
Ultimately, treatment is based on what an owner is able or
willing to do for a pet. "There is no right or wrong," says Dr.
Messonnier. Twice-weekly acupuncture may not be possible for
those who don't have transportation, so they prefer to give
pills.
"There is an additional cost for pain relief," says Reding.
Clinics may charge an extra $40 to $60 for a Fentanyl patch, for
example.
Some clinics cut costs by eliminating pain medicine, says Dr.
Messonnier. "Don't assume your veterinarian already uses pain
management," he says. "If the spay only costs $50, a light needs
to go off - ask!" Be aware that anesthetic does not address pain.
Dr. Messonnier says that ketamine (a common injectable
anesthetic) only controls superficial pain, and does not block
the visceral pain that results from spay surgery.
The latest research makes it clear that pain is an important
health issue for cats and dogs. Whatever their condition,
providing proper pain management always enriches their quality of
life and can help them recover more quickly and completely. It's
also an ethical obligation. For those who love cats and dogs,
making the hurt go away is simply the right thing to do.
Amy D. Shojai, of Sherman, Texas, has written a dozen books on
dog and cat health care and behavior. For a list of titles, visit
www.shojai.com.
© 2003 ASPCA
ASPCA Animal Watch - Spring 2003
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