Health Tip: Understanding Antibiotic Resistance

(HealthDay News) -- Antibiotic resistance occurs when bacteria mutate and make certain medications ineffective in preventing bacterial infections.

The U.S. Department of Health and Human Services offers these suggestions for preventing antibiotic-resistant infections:

• Talk to your doctor about whether you actually need an antibiotic to treat a particular illness.
• Don't take antibiotics when they are not helpful. For example, antibiotics will not treat infections caused by viruses, including the common cold and the flu.
• Always take antibiotics as prescribed by your doctor. Don't skip any dose, and don't stop taking them early, even if you feel better.
• Never "save" antibiotics to take later. Never re-use them for a different illness.
• Never take an antibiotic that was prescribed to another person.

Beta Blocker Use Questioned in Non-Heart Surgery

(HealthDay News) -- An analysis of 33 studies on drugs known as beta blockers has concluded that they are not useful in any surgical procedure other than heart surgery. In fact, using beta blockers for non-coronary surgery may actually increase the risk of stroke, the scientists say.

The researchers who conducted the study -- known as a meta-analysis -- recommend that the guidelines committees of both the American College of Cardiology and the American Heart Association "soften" their recommendations that beta blockers be used to prevent surgical complications in non-coronary operations.

"Our study says that if you look at the overall picture, do a meta-analysis, studies that are not particularly well-done come to the conclusion that they are useful," said Dr. Franz Messerli, professor of medicine at Columbia University and an author of a report published online by The Lancet to coincide with the annual heart meeting now underway. "But if you look at the high-quality studies, there are distinctly more strokes with beta blockers." Beta blockers are drugs that inhibit adrenaline and slow the nerve impulses to the heart. They can also be used to treat irregular heartbeat, known as arrhythmia.

The meta-analysis did show a 35 percent reduced risk of heart attacks and a 64 percent reduction in less serious heart artery blockages among the more than 12,000 participants in all the studies where beta blockers were prescribed before surgery. But there was no overall reduction in total deaths, heart failure or deaths due to heart disease, and a doubled risk of nonfatal stroke.

Beta blocker usage was also associated with a high risk of bradycardia, low heart rate requiring medical treatment, which occurred in 1 of every 22 people getting beta blockers, and of lower blood pressure dangerous enough to require treatment.

In September 2008, researchers writing in the Journal of the American College of Cardiology concluded that beta blocker drugs don't prevent development of heart failure in people with high blood pressure and should not be used as first-line treatment for hypertension.

The increased risk of stroke, occurring in 1 of every 293 beta blocker recipients, is especially important, Messerli said. "Stroke is one of the most devastating complications of cardiovascular disease," he said. "For that reason, we would be very reluctant to use beta blockers in noncomplicated patients."

There is a presurgical role for beta blockers in many cases, Messerli said. "If a patient has coronary artery disease, he or she should certainly be on beta blockers," he said. "If they are on beta blockers already, they should remain on beta blockers. But if there is no particular cardiovascular risk, beta blockers should not be prescribed for noncardiac procedures."

Existing recommendations that call for routine use of beta blockers before surgery should be revised, Messerli said. "This is regarded as a quality measure for physicians," he said. "If they don't prescribe a beta blocker, it is considered to be falling short of a quality measure. Since the data are relatively soft, it certainly should not be a quality measure."

But an argument for use of beta blockers before surgery was made in an accompanying comment to the study by Dr. Don Poldermans, professor of medicine at Erasmus Medical Center in Rotterdam, the Netherlands. One major problem with studies showing difficulties when beta blockers were prescribed was that the doses were too high, Poldermans said.

"A low dose is safe, so why not use it?" Poldermans said, citing a study that he presented to the American Heart Association's annual scientific sessions, in New Orleans.

The study of 1,066 people who underwent surgery and were classified as being of intermediate risk of cardiovascular complications found that 2.1 percent of those getting a moderate daily dose of bisoprolol, a widely used beta blocker, suffered heart attacks or died of heart disease, compared to 6 percent of those not getting the beta blocker, Poldermans reported.

What might help decide the issue would be "a study to clarify dose and regimen" of beta blockers before surgery, he said. But such a study might be difficult to do, because the dangers of high-dose beta blockers are clear, Poldermans said.

"I would be very careful with high doses of beta blockers," he said. "There could be an increased risk of stroke. But a low dose is safe, so why take a high dose?"

More information
Learn why and how beta blockers are used from the Texas Heart Institute.

Colon Cancer Drug Won't Help Those With Certain Gene Mutation

(HealthDay News) -- A new study suggests that people with advanced colon cancer who have a particular gene mutation won't benefit from the medication cetuximab (Erbitux).

While the drug can add months to the lives of people without a mutation in a gene called K-ras, those who have the mutation won't see any benefit from this additional therapy, reports the study, which is published in the Oct. 23 issue of the New England Journal of Medicine.

"We believe that, in the context of pre-treated advanced bowel cancer, the K-ras mutation status of the cancer should be determined before using cetuximab, and cetuximab should only be given to patients with tumors that do not have the mutation," said study author Dr. Christos S. Karapetis, a senior consultant medical oncologist and director of clinical research in the department of medical oncology at Flinders Medical Centre in Australia.

Karapetis said that about four in 10 people with colon cancer have the K-ras mutation.

Erbitux works by interrupting cell growth and division. It does this by binding to a receptor known as epidermal growth factor receptor (EGFR). A mutation in the K-ras gene is believed to interfere with cetuximab's ability to disrupt EGFR, according to the study.

For the study, 572 people with advanced colorectal cancer were randomly assigned to receive either weekly treatment with cetuximab and supportive care (287 people) or supportive care alone (285 people). All had undergone other treatment options without success.

Almost 400 tumor specimens from the study volunteers were tested for K-ras mutations (198 from the cetuximab group and 196 from the supportive care group). Just over 42 percent of the tumors evaluated were found to have mutations in the K-ras gene.

Even with cetuximab treatment, people with K-ras mutations had no significant changes in overall survival or in progression-free survival. Those without the mutations, on the other hand, appeared to benefit significantly from the therapy.

People with no K-ras mutations who were treated with cetuximab had nearly twice the overall survival rate compared to the supportive care group -- 9.5 months versus 4.8 months. And, the time of progression-free survival was also nearly doubled for those treated with cetuximab -- 3.7 months versus 1.9 months in the supportive care group.

"Patients with a colorectal tumor bearing mutated K-ras did not benefit from cetuximab," the researchers concluded.

"This study suggests that if someone has this particular mutation, they won't respond to this drug," said Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society. "The bottom line is that this study is important and really has the potential to impact how we treat patients with colorectal cancer with this very expensive drug."

He added that other researchers have noted similar results for K-ras mutations in earlier-stage colorectal cancer.

"This is one more refinement on personalized medicine, and we're moving into an age of molecular markers that eventually will guide treatment. If someone has a cancer in the future, that cancer will be analyzed for what kind of cancer it is, and then we'll know what the best treatments are for that cancer," Lichtenfeld said.

Another important molecular marker that guides treatment is already in use for breast cancer treatment, according to Lichtenfeld. Breast cancers are tested for a type of receptor called HER2. Those with this molecular marker are likely to have a more aggressive type cancer, but also a type of cancer that responds to treatment with the drug trastuzumab (Herceptin), he said.

"I'm excited about the future, and this study shows we can be more targeted with our targeted therapies," said Lichtenfeld.

More information
To learn more about colon cancer treatment options, visit the National Cancer Institute.

Cholesterol-Lowering Drugs Will Wreck Your Muscles

Cholesterol-lowering “statin” drugs often come with side effects. The most frequently reported consequence is fatigue, and about 9 percent of patients report statin-related pain.

The results of a new study show that statins at higher doses may also affect the ability of the skeletal muscles -- which allow your body to move -- to repair and regenerate themselves.

The study examined the proliferative capacity of human satellite cells when exposed to the statin simvastatin. They found that higher end concentrations of the drug led to reduced proliferation, which would likely negatively affect the muscle's ability to heal and repair itself.

Sources:
Eurekalert September 25, 2008

Alcohol, Drug Counseling Benefits Teens, Too

(HealthDay News) -- Alcoholics Anonymous and Narcotics Anonymous offer benefits to adolescents, even if they eventually stop attending meetings, says a study that included 160 teens enrolled at two treatment centers in California.

The teens, with an average age 16, stayed from four to six weeks at the centers, which were focused on abstinence and used a 12-step model. The teens were reassessed at six months, and one, two, four, six, and eight years after they left the centers.

"We found that most of the youth attended at least some AA/NA meetings post-treatment," John F. Kelly, associate director of the MGH-Harvard Center for Addiction Medicine at Massachusetts General Hospital, said in a prepared statement.

"Those patients with severe addiction problems and those who believed they could not use alcohol/drugs in moderation attended the most. The NA and AA focus on abstinence/recovery probably resonates better with these more severely dependent individuals who also typically need ongoing support," said Kelly, who's also an assistant professor in psychiatry at Harvard Medical School.

While many of the study participants eventually stopped going to AA/NA meetings, they seemed to benefit from their time with the organizations.

"We found that patients who attended more AA and/or NA meetings in the first six months post-treatment had better longer term outcomes, but this early participation effect did not last forever -- it weakened over time," Kelly said.

"The best outcomes achieved into young adulthood were for those patients who continued to go to AA and/or NA. In terms of a real-world recovery metric, we found that for each AA/NA meeting that a youth attended, they gained a subsequent two days of abstinence, independent of all other factors that were also associated with a better outcome."

Kelly noted that even a little exposure to AA/NA can go a long way.

"During the first six months post-treatment, even small amounts of AA/NA participation -- such as once per week -- was associated with improved outcome, and three meetings per week was associated with complete abstinence. This suggests youth may not need to attend as frequently as every day, sometimes recommended clinically, to achieve very good outcomes," Kelly said.

The study was published online in the journal Alcoholism: Clinical and Experimental Research and was expected to be in the August print issue.

More information
The Nemours Foundation has more about teens and alcohol.