Study warns of common antibiotic's glucose risks
CTV.ca News Staff

A new Canadian study is warning that a commonly prescribed antibiotic is associated with an increased risk of potentially life-threatening blood sugar abnormalities.

Gatifloxacin, sold under the brand name Tequin by manufacturer Bristol-Myers Squibb, is linked with an increased danger of blood sugar fluctuations when compared to other antibiotics in the same drug class, according to a warning from a Canadian study that was published online by The New England Journal of Medicine.

The study was to be published in the journal in late March but it was released early because of its important public health implications.

"Gatifloxacin is one member of a class of antibiotics called fluoroquinolones, which are currently the most prescribed antibiotics in North America," the study's lead author Dr. Laura Park-Wyllie, and research fellow for the Toronto-based Institute For Clinical Evaluative Services said in a written statement.

"However, in recent years, several other fluoroquinolones have been withdrawn or restricted because of serious adverse events. Several reports suggest that gatifloxacin is particularly prone to influence blood glucose levels."

Researchers studied the association between antibiotic use and subsequent hospital visits for high and low blood sugar levels, in Ontario residents aged 66 years and older between April 2002 and March 2004.

The results showed that patients treated for low blood sugar levels were more than four times more likely to have received gatifloxacin in the preceding 30 days, compared to other common antibiotics.

Researchers also found that patients hospitalized with high blood sugar levels were almost 17 times more likely to have been treated with gatifloxacin, than with other antibiotics in the preceding 30 days.

While it's unusual for a drug to have two opposing effects, it's believed Tequin may interfere with regulation of insulin secretion from the pancreas, which controls blood sugar levels.

According to the study, the risk of blood sugar abnormalities was not restricted to patients with diabetes.

In contrast, no significant increased risk of low or high blood sugar levels was seen with any other drug from the same class of antibiotics.

Low blood sugar symptoms include confusion, lightheadedness, shakiness, perspiration, palpitations, and trouble speaking. If the levels drop further, a person may experience seizures, coma, and even death.

Meanwhile, high blood sugar symptoms include excessive urination and thirst, confusion, and nausea. Similarly, the condition can escalate to the point of coma and death.

"Here's a drug with side effects that are potentially fatal, that are difficult to predict. �?Knowing what I know, I would never prescribe this antibiotic again," study co-author Dr. David Juurlink of the Toronto-based Institute For Clinical Evaluative Services told CTV News.

Gatifloxacin is typically taken to treat patients with pneumonia, bronchitis, gonorrhea and other infections, such as those affecting the skin, urinary tract or kidneys.

"This is a big deal. This is a drug that is prescribed 5,000 times a day in the U.S., 500 times a day in Canada. And if the numbers that we find apply to this population, we are talking about, literally, dozens of people, who getting into trouble every day with high blood sugar or low blood sugar as a result of this," Juurlink said.

Some Canadian hospitals noted that the drug caused problems with patients and stopped using this antibiotic more than two years ago.

"Patients usually within 24 hours of receiving a dose of the antibiotic would have a marked drop in their blood sugar," Dr. Gerald Evans of Kingston General Hospital told CTV News.

After the team at Kingston General counted seven patients with the same side effects, they quickly pulled the drug.

"Here at Kingston General Hospital ... we felt it was the right thing to do, and it's been borne out now, two years later, that it was the right decision," Evans said.

There have been 14 deaths in Canada potentially linked to blood sugar abnormalities among Tequin users since the drug was approved in 2001, The Canadian Press reported.

The cases are still being reviewed and no link between the drug and the deaths has been established.

As of December 31, Health Canada had also received 169 reports of low blood sugar and 109 reports of high blood sugar possibly related to the drug.

In February of this year, both Health Canada and the U.S. Food and Drug Administration issued warnings advising diabetic patients, as a precaution, not to use the antibiotic due to concerns about blood sugar levels.

Health Canada plans to update safety information on the drug's labelling and is considering whether that should include a "black box" warning, which is issued when a drug is potentially lethal, spokeswoman Jirina Vlk told CP.

"We need to try to determine can we can maximize the benefits of this drug and minimizing its risks," Health Canada's Kimby Barton said.

It's yet unclear whether the drugmaker itself will issue new warnings, said Bristol-Myers Squibb in Canada spokesman Marc Osborne.

"Tequin is generally well-tolerated in appropriate patients," he said.

With a report from CTV's Avis Favaro
From:   http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20060301/antibiotic_bloodsugar_060301/20060301?hub=TopStories

 

Regulators probing antibiotic linked to U.S. death
Jan. 21 2006,  Canadian Press

WASHINGTON �?Researchers reported Friday three cases of severe liver problems, including one death, in patients at a North Carolina hospital after they began taking a novel antibiotic.

Federal regulators said they were reviewing an unknown number of U.S. cases involving the drug, telithromycin, and were consulting with their counterparts overseas.

One patient at Carolinas Medical Center in Charlotte, N.C., died after taking telithromycin, which is marketed as Ketek, researchers at the hospital said. Another required and received a liver transplant, while the third recovered from drug-induced hepatitis after treatment with Ketek was stopped.

The severity of the cases warranted the researchers' alerting doctors to what they called a "possible link with telithromycin," said Dr. John Hanson, who works in the liver transplant centre at Carolinas Medical Center.

The reports do not prove the drug caused the problems, researchers said. Nor is there enough information to support major changes in how the drug is prescribed, Hanson said. Two of the three patients reported some use of alcohol, although there was no prior evidence of liver damage.

The cases are discussed in a paper to be published March 21 in the journal Annals of Internal Medicine. The journal released an electronic version on Friday.

The drug is made by Sanofi-Aventis. A company spokeswoman did not immediately return a message seeking comment left midday Friday.

The Food and Drug Administration approved the drug, marketed as Ketek, in 2004 for treatment of acute bacterial infections from chronic bronchitis, acute bacterial sinusitis and community-acquired pneumonia. On Friday, FDA spokeswoman Susan Bro said the agency would comb through its databases for other reports of liver problems in patients treated with the drug.

"Because these liver problems are significant and somewhat idiosyncratic or unpredictable, the FDA is evaluating the use of this medicine in both the U.S. and abroad where it is used and marketed to determine whether additional warning guidance is merited," Bro said.

A spokesperson for Health Canada said it was looking into the findings. Christopher Williams said the department had searched its adverse drug reaction database, but had found no reports of liver problems related to use of the drug.

Bro cautioned that patients on the drug who experience any sort of liver distress, including jaundice, should talk to their doctors immediately.

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