Zithromax antibiotics tied to rare heart risks

istockphoto

(AP) CHICAGO -- An antibiotic widely used for bronchitis and other common infections seems to increase chances for sudden deadly heart problems, a rare but surprising risk found in a 14-year study.

Zithromax, or azithromycin, is more expensive than other antibiotics, but it's popular because it often can be taken for fewer days. But the results suggest doctors should prescribe other options for people already prone to heart problems, the researchers and other experts said.

Vanderbilt University researchers analyzed health records and data on millions of prescriptions for several antibiotics given to about 540,000 Tennessee Medicaid patients from 1992 to 2006. There were 29 heart-related deaths among those who took Zithromax during five days of treatment. Their risk of death while taking the drug was more than double that of patients on another antibiotic, amoxicillin, or those who took none.

To compare risks, the researchers calculated that the number of deaths per 1 million courses of antibiotics would be about 85 among Zithromax patients versus 32 among amoxicillin patients and 30 among those on no antibiotics. The highest risks were in Zithromax patients with existing heart problems.

Patients in each group started out with comparable risks for heart trouble, the researchers said.

The results suggest there would be 47 extra heart-related deaths per 1 million courses of treatment with Zithromax, compared with amoxicillin. A usual treatment course for Zithromax is about five days, versus about 10 days for amoxicillin and other antibiotics. Zithromax is at least twice as expensive as generic amoxicillin; online prescription drug sellers charge a few dollars per pill for Zithromax.

"People need to recognize that the overall risk is low," said Dr. Harlan Krumholz, a Yale University health outcomes specialist who was not involved in the study. More research is needed to confirm the findings, but still, he said patients with heart disease "should probably be steered away" from Zithromax for now.

The study appears in Thursday's New England Journal of Medicine. The National Heart, Lung and Blood Institute helped pay for the research.

Zithromax, marketed by Pfizer Inc., has been available in the United States for two decades. It's often used to treat bronchitis, sinus infections and pneumonia. Wayne Ray, a Vanderbilt professor of medicine, decided to study the drug's risks because of evidence linking it with potential heart rhythm problems. Also, antibiotics in the same class as Zithromax have been linked with sudden cardiac death.

Zithromax is among top-selling antibiotics. U.S. sales last year totaled $464 million, according to IMS Health, a health care information and services company.

Pfizer issued a statement saying it would thoroughly review the study. "Patient safety is of the utmost importance to Pfizer and we continuously monitor the safety and efficacy of our products to ensure that the benefits and risks are accurately described," the company said.

Patients studied were age 50 on average and not hospitalized. Most had common ailments, including sinus infections and bronchitis. Those on Zithromax were about as healthy as those on other antibiotics, making it unlikely that an underlying condition might explain the increased death risk.

Medicaid patients generally have more disability and lower incomes than other patients, so whether the same results would be found in the general population is uncertain, Ray said.

Dr. Bruce Psaty, a professor of medicine at the University of Washington, said doctors and patients need to know about the potential risks. He said the results also raise concerns about long-term use of Zithromax, which other research suggests could benefit people with severe lung disease. Additional research is needed to determine if that kind of use could be dangerous, he said.

[leepdx]

I had a sinus infection two months ago that developed into pnemonia. The doctor prescribed this drug and after 3 days my heart started feeling strange. It still feels odd, I am very worried it has done permanent damage. Why don't the doctors prescribe penicillin anymore? I rarely take medication so it should have been sufficient for my circumstance.

[PFGRIMES76]

This is a real story, I have over $400,000 in medical bills to prove and I have a 25 year old son whose heart is failing. About three years ago he had a bad sinus infection. He is allergic to all the ..cillins, like penicillin and others. The doctor gave him Z-Pack. A week later, he was in the hospital with pneumonia for five days. He came home on a Friday. By Saturday night he could not get out of a chair. I had push him to the car on a chair and take him to the hospital. His heart was failing. He weighed over 300 pounds due to the buildup of fluid in his body. His ejection fraction was 10 out of 60. (Ejection Fraction measures how well the heart pumps blood, 60 is normal.) At that time he was already a candidate for a heart transplant.

Today his ejection fraction is 25 out of 60. He takes 20 pills a day. He cannot over exert himself, and worst of all, he knows that one day he will need a heart transplant.

Once the heart is damaged, it can never recover. Other than a heart transplant, his only hope comes from new therapies using stems cells from his own body.

Pfizer sold $464 million dollars of their drug last year alone. Over 20 years they have sold close to $2 billion.

We all take risks in our lives every day. When we get in a car, eat a meal at a restaurant, or even when we buy bean sprouts at the store. This I accept. Therefore, when the companies that sell us the things we use in our lives make a mistake, and cause harm, they must make it right.

My son faces a $1,000,000 heart transplant one day. He goes through each day not knowing if his next cold may turn into an infection that his heart and immune system cannot fight off.

Needless to say, I will be collecting data and contacting lawyers very soon.

[nohater]

who is ultimately responsible? is it drug companies, doctors who prescribe medications, people who take any pill whether over the counter or prescribed without truly knowing the side effects and other pitfalls associated with taking the pills? always ask myself, do i really need to take this pill? as well as, is there another way to deal with this issue?

[smittyc]

Really sounds like they are jumping the gun here. They had to extrapolate the numbers to a million and compare it to one of the safest antibiotics on the mkt, amoxicillin which is a penicillin. I'd say not enough data available for this level of condemnation. I would also like to know what type of heart attacks are they referring to?