A postoperative pop of pain relief
By Liz Devitt
Research shows that novel drug formulation works in just one shot
When our pets hurt we ache for them, but managing pain in pets isn’t easy. Even though pain is considered the fourth vital sign, it’s hard to treat when animals hide their discomfort and when many medications prescribed for people are not as effective or have not been validated as effective in pets.
Dr. Lesley J. Smith (at left with her dog, Wilma), a board-certified veterinary anesthesiologist at the University of Wisconsin, knows the importance of pain management firsthand. She remembers how, years ago, when her first dog developed complications from cancer and needed limb amputation surgery, she had to scramble to get more medication when the analgesics her dog had already taken weren’t strong enough to keep the pain at bay. More recently, Morris Animal Foundation funding allowed Dr. Smith to study a better way to treat postsurgical pain in dogs.
“Right now, our standard of care for relief of severe pain requires an intravenous catheter, intensive care nursing and continuous infusions of drugs,” Dr. Smith explains. “Currently, there’s nothing commercially available that is effective, long lasting and easily administered. Our study looked at a single-injection drug, given under the skin, that lasts at least three days.”
What’s the wonder drug? Hydromorphone, an opioid that has provided pain relief for decades. Although the drug is commonly used, a new formulation makes it easier to administer. Dr. Smith and her co-investigators reformulated hydromorphone into a lipid-based vesicle—called a liposome—that slowly releases the drug to deliver a steady stream of pain relief.
“Most people are familiar with patient-controlled analgesia, where a person has an IV catheter and pushes a button for more medication,” Dr. Smith says. “Our pets can’t do that for themselves, though, so this formula of the drug DPPC-C hydromorphone is a chemical way to achieve that.”
In earlier research, also funded by Morris Animal Foundation, Dr. Smith and Dr. Lisa Krugner-Higby studied the metabolism and side effects of DPPC-C hydromorphone in a group of healthy Beagles.
Using the information they collected, they studied the new hydromorphone formulation in pets that needed major surgery. Their results show that a single dose of DPPC-C hydromorphone is as effective as the current standard of care for pain relief. An added bonus is that it doesn’t cause unexpected side effects and requires far less intensive care.
Although there aren’t any plans to commercialize this drug formulation right now, Dr. Smith’s work paves the way for finding other formulations of longacting pain medications. With less pain, our pets have everything to gain.
Posted by MAfon May 18, 2012. Permalink