One of the most commonly prescribed classes of antibiotics may be associated with two types of heart problems, a study claims.
The study, published in the Journal of the American College of Cardiology, found that current users of fluoroquinolone antibiotics, such as Ciprofloxacin, face a 2.4 times greater risk of developing aortic and mitral regurgitation, where the blood backflows into the heart, compared to patients who take amoxicillin, a different type of antibiotic.
The greatest risk is within 30 days of use, according to the researchers at the University of British Columbia (UBC) in Canada.
Recent studies have also linked the same class of antibiotics to other heart problems, they said.
Some physicians favour fluoroquinolones over other antibiotics for their broad spectrum of antibacterial activity and high oral absorption, which is as effective as intravenous, or IV, treatment.
"You can send patients home with a once-a-day pill," said Mahyar Etminan, an associate professor at UBC.
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"This class of antibiotics is very convenient, but for the majority of cases, especially community-related infections, they're not really needed. The inappropriate prescribing may cause both antibiotic resistance as well as serious heart problems," said Etminan.
The researchers hope their study helps inform the public and physicians that if patients present with cardiac issues, where no other cause has been discovered, fluoroquinolone antibiotics could potentially be a cause.
"This study highlights the need to be thoughtful when prescribing antibiotics, which can sometimes cause harm," said Bruce Carleton, a research investigator at UBC Children's Hospital.
Scientists analysed data from the US Food and Drug Administration's adverse reporting system.
They also analysed a massive private insurance health claims database in the US that captures demographics, drug identification, dose prescribed and treatment duration.
Researchers identified 12,505 cases of valvular regurgitation with 125,020 case-control subjects in a random sample of more than nine million patients.
They defined current fluoroquinolone exposure as an active prescription or 30 days prior to the adverse event, recent exposure as within days 31 to 60, and past exposure as within 61 to 365 days prior to an incident.
Scientists compared fluoroquinolone use with amoxicillin and azithromycin.
The results showed that the risk of aortic and mitral regurgitation, blood backflow into the heart, is highest with current use, followed by recent use, researchers said.
They saw no increased risk of aortic and mitral regurgitation with past use.