WBRZ - Baton Rouge

BATON ROUGE - A new study claims the antibiotic azithromycin, also known as a Z-Pak, could increase your risk of death.

It claims people with cardiovascular problems who take the antibiotic are in the most danger.

According to the study published in the New England Journal of Medicine, last year 55.3 million people were prescribed the drug.

Dr. Wayne Ray, professor of preventive medicine at Vanderbilt University, in Nashville, Tenn., is the lead author of the study.

Ray's study looked at Medicaid patients from 1992 to 2006 and found that patients on azithromycin had two and a half times the odds of dying from a cardiovascular cause while taking the medicine than patients on amoxicillin.

Both azithromycin and amoxicillin are commonly prescribed to help fight off bacterial infections.

People we spoke to say the news is alarming.

"That goes on all the time. They prescribe you a medicine that does one thing and then in the background it's doing something else," said Janice Ihaca.

Billy Williamson has a family history of heart problems and says it makes him think twice about the medicine he says works.

"It's something that's kind of near and dear to me; my father is a heart transplant recipient so its something that I think I'm genetically predisposed for," said Williamson.

According to the study doctors commonly prescribe a Z-Pak because its fewer pills to take in less days, which means people are more likely to finish their medicine. Despite this, Ray says the risk of death outweighs the convenvience of the medicine in high-risk patients.

Ray and his colleagues found the antibiotic could cause irregular heartbeats, which can sometimes lead to death. While doctors we spoke to agree the findings are worrisome, they say if you're concerned talk to your doctor.

Pfizer makes the drug and said in a written statement it will review the new study and that "patient safety is of the utmost importance."