Popular antibiotic class linked to heart valve problems

While antibiotics are a normal part of everyday life for people all over the world, researchers at UBC are raising important questions about the side effects of a popular class of such medicines.

A study conducted by Dr. Mahyar Etminan, associate professor in the department of ophthalmology and visual sciences, alongside fellow associate members in the departments of medicine and pharmacology, indicates that a familiar class of antibiotics known as fluoroquinolones causes users to have a 2.5 times greater risk of experiencing adverse heart valve problems. This is in comparison to other commonly prescribed antibiotics like the bacteria-fighting amoxicillin.

“We have been looking at different side effects with this class of antibiotics for actually a few years now. We’ve looked at other types of side effects like ocular, also neurologic, and the [US] Food and Drug Administration (FDA) last year put an alert on these drugs, specifically with a link to aortic aneurysms,” said Etminan, who partnered with the Provincial Health Services Authority on the research.

“We thought that if it can damage the vessels, then it can potentially damage the heart valves as well, but no one really had looked at that, at that time, so we thought we would be the first group to look at it and see if there is a risk or not.”

Through a health trade database in the United States, the researchers accessed information regarding physician diagnosis, medical diagnosis, hospitalization and prescription drugs for a population of about nine million study enrolees. The data led researchers to conclude that fluoroquinolones are associated with higher risk of heart valve complications.

The results of the research cast doubt on why fluoroquinolones are prescribed in place of antibiotics that are associated with lower risk of developing heart issues.

The popularity of fluoroquinolones comes from the abilities of these antibiotics to cover a wide range of disease-causing bacteria, which makes them highly effective workers in the face of a collection of different illnesses.

Fluoroquinolones, when ingested orally, are also close to 100 per cent absorbed, making them very similar in productivity to all-purpose IV fluids delivered directly to the veins. This efficiency of absorption associated allows physicians to prescribe these antibiotics to patients without having to hospitalize them.

In light of this, Etminan stressed that fluoroquinolones play an important therapeutic role, but their usage should be selective.

“... Their role is mostly in patients who have very serious infections,” he said.

“Unfortunately, we know that for the most part when they are used in the community, they are used in cases where either antibiotics are not needed, or other safer types of antibiotics could also have been used.”

It often takes time for physicians to acknowledge new scientific findings related to drug prescription and usage. For this reason, although new discoveries are being made, physicians can be slow in processing and altering treatment practices to accommodate findings.

Through his research, Etminan hopes to raise awareness of the side effects associated with fluoroquinolones, while also encouraging better consideration of the increase in bacterial resistance as a result of over-prescribing this class of antibiotics.

The researchers hope that further studies will accentuate the complexity of the link between fluoroquinolones and heart complications.

“The more studies validate and confirm our findings, then that would prompt … health regulatory bodies like the FDA and Health Canada to put a warning on this,” said Etminan.