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Entries in Opioids (2)

Wednesday
Mar212012

Do Opioids Play Role in Cancer Growth?

iStockphoto/Thinkstock(NEW YORK) -- When Dr. Jonathan Moss was developing a drug to relieve the severe constipation plaguing end-stage cancer patients taking opioid painkillers, he noticed a few of those patients lived longer than expected.

Although likely to die within a month, some "went on to live for five to six months," Moss said.  He began to think the methylnaltrexone (Relistor) might be doing more than simply improving their ability to eat.

"I began to wonder in my mind…could it be an effect on the progression of the tumor?" he said.

Subsequent laboratory studies confirmed that Relistor inhibited tumor growth and angiogenesis -- the sprouting of blood vessels that nourish tumors.

Now, almost a decade later, multiple laboratory and animal studies, are converging with some human research to suggest that opioid drugs and the body's natural opioids may play a role in the growth and spread of cancer, according to two studies and an accompanying commentary published Tuesday in a special issue of the journal Anesthesiology.

Moss, co-author of the commentary and one of the studies, cautioned that it would be premature for cancer patients or their doctors to give up on opioids, which have a 200-year history in relieving cancer pain and post-surgical pain.

"There are no double-blind human studies showing that if you take an opioid, that you are more or less likely to have tumor progression," said the professor of anesthesiology and critical care medicine at the University of Chicago.

Without proof provided by a "large human study," the findings are "very interesting," but "much too early" to change practices, said Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Clinic Foundation and Hospital in Baton Rouge, La.  He expressed concern that cancer patients might become unnecessarily worried that pain meds will make their cancers grow.

In one of the new studies, breast cancer patients survived longer if they had a gene that made them resistant to opioids (meaning they probably needed more medication to control their pain).  In the Carolina Breast Cancer Study of more than 2,039 women diagnosed between 1993 and 2001, women with invasive breast cancer who had one copy of the gene variant survived twice as long.  Survival quadrupled for those with two copies of the gene variant, according to research led by Dr. Andrey V. Bortsov, an assistant professor of anesthesiology and his colleagues at the University of North Carolina, Chapel Hill.

In the other study, led by Patrick A. Singleton, an assistant professor of medicine at the University of Chicago, researchers found that naturally occurring opioids could fuel the growth of human non-small cell lung cancer in human lung cancer cells transplanted into mice with compromised immune systems.

"What we saw was a two-fold increase in tumor growth, and even more strikingly, a 20-fold increase in metastasis," he said in an interview.

"The two papers together are really bookends," Moss said.  The finding that lung cancer cells have lots of so-called mu opioid receptors involved in tumor growth and spread provides "a plausible explanation for what people in North Carolina have found.  The mu opioid receptor may be very importantly involved in the progression of tumors."

As a result, he said that receptor could become a therapeutic target for new cancer drugs.

Copyright 2012 ABC News Radio

Monday
Mar122012

Prescription Painkillers for Small Surgeries May Lead to Long-Term Use

iStockphoto/Thinkstock(TORONTO) -- Older adults who receive pain medications after surgery may be at higher risk of becoming addicted, according to a new study published in the journal Archives of Internal Medicine.

Physicians often prescribe opioids, including codeine and oxycodone, after outpatient surgeries.

While these drugs are proven to be effective for temporary pain relief, they are also associated with side effects including sedation, constipation and breathing problems, as well as addiction.

Researchers analyzed data from nearly 400,000 Canadian patients ages 66 and older who received an opioid prescription within seven days of undergoing surgery for cataracts, gallbladder removal, prostate tissue removal or varicose vein stripping.

What they found was that more than 10 percent of the patients who received an opioid after a surgery were identified as long-term opioid users one year after surgery. They also found patients were 3.7 times more likely to use non-steroidal anti-inflammatory drugs on a long-term basis if they received a prescription for the drug within seven days after surgery.

"We tried to look at what some of the events are that start people on the road to acute or chronic use of opioids," said Dr. Chaim Bell, associate professor of medicine at University of Toronto and co-author of the study. "It's much easier to prevent the initiation of the medication than wean people off it later. Everyone should get pain relief, but the painkiller and the dose should be tailored to the specific patient."

The findings align with the general experience of Dr. David Maine, director of the Center for Interventional Pain Medicine. He said the decision to start and prescribe an opioid at any time is a serious one. Treatment goals should be clearly defined when a prescription is first written, to ensure safety and effectiveness of the medication -- and to minimize the risk of addiction.

"Generally with older patients, if starting an opioid, we set up a short interval follow-up to ensure tolerability of the medication as well as efficacy," said Maine. "If either of those are an issue then we make a change. Sometimes that change is discontinuing the medication entirely. Ultimately, I think the decision to stop an opioid analgesic is as important as the decision to start."

Dr. Timothy Collins of the Pain and Palliative Care Program at Duke University Medical Center said the results of the study are surprising since patients who undergo such small surgeries should be finished with their pain medications after 10 to 14 days.

"Changes in the way pain medications are prescribed such as linking the pain medication to a specific outcome would help," said Collins. "Patients would have to have better function, or significant improvement on a pain scale, in order to continue on the medication. Frequently patients just say 'I feel better' or 'it helps some' but do not have any other evidence that the medication is actually helping them function better."

One in five American adults received a painkiller prescription in 2006, totaling more than 230 million total prescription painkiller purchases.

And in 2010, the Centers for Disease Control and Prevention reported that the number of fatal opioid poisonings more than tripled from 4,000 in 1999, to 13,800 in 2006.

Lack of communication between surgeons and family physicians may contribute to excessive painkiller prescriptions, along with the potential addiction and abuse of them, Bell said. Communication barriers, such as hearing or cognition deficits in older patients, also may hinder patients' understanding of when it is appropriate to taper a pain medicine or take it only on an as needed basis, said Dr. Doris Cope, director of the Pain Medicine Program at University of Pittsburgh Medical Center.

The study emphasizes the importance of tailoring patient education on a case-by-case basis, as well as the need for careful coordination of medical care among a patient's surgeons, doctors and caregivers, said Cope. Hopefully, she added, "this can be better achieved in the offices of busy primary care physicians."

Copyright 2012 ABC News Radio







ABC News Radio