VANCOUVER, British Columbia — Ever since Sir Alexander Fleming first discovered penicillin in 1928, antibiotics have helped millions of people treat and overcome bacterial infections of all kinds. Today, antibiotics are prescribed frequently and generally considered safe by both physicians and patients. However, a new study has discovered that fluoroquinolones, a widely used and prescribed class of antibiotics, are linked to an increased risk of developing two serious heart conditions.
Working in unison with the Provincial Health Services Authority’s (PHSA) Therapeutic Evaluation Unit, a team of researchers from the University of British Columbia have found that fluoroquinolone antibiotics users face a 2.4 times higher risk of developing both aortic and mitral regurgitation in comparison to patients who take amoxicillin, a different class of antibiotic. Both of these conditions can cause blood to leak back into the heart, and both can cause serious issues such as atrial fibrillation and heart failure if left unchecked.
According to the study’s findings, patients are most at risk within 30 days of using fluoroquinolone antibiotics. Fluoroquinolones are prescribed under an assortment of different names, including Ciprofloxacin and Cipro.
Researchers say that fluoroquinolones are prescribed so often by physicians because they are effective against a broad array of bacteria, and boast a high absorption rate.
“You can send patients home with a once-a-day pill,” explains Mahyar Etminan, lead author and associate professor at UBC, in a release. “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.”
The study’s authors are hopeful that physicians will keep their findings in mind when determining the cause of heart problems in patients; if no other underlying cause for a problem is found, the use of fluoroquinolone antibiotics may be the root cause.
“One of the key objectives of the Therapeutic Evaluation Unit is to evaluate different drugs and health technologies to determine whether they enhance the quality of care delivered by our programs or improve patient outcomes,” says Dr. Bruce Carleton, director of the unit and research investigator at BC Children’s Hospital, a program of PHSA. “This study highlights the need to be thoughtful when prescribing antibiotics, which can sometimes cause harm.”
To come to their conclusions, the research team analyzed data collected by the FDA, as well as a private health insurance claims U.S. database that included patient demographics, drug names, doses prescribed, and duration of treatment. Using these databases, researchers extracted a combined pool of more than nine million randomly selected patients’ worth of data. Then, they identified 12,505 patients diagnosed with valvular regurgitation and compared them to a control group of 125,020 other patients.
Active fluoroquinolone use among patients was defined as any patient actively using a prescription or any patient who had taken the antibiotic 30 days before a cardiac event or development. Recent use was defined as any patient who had taken the antibiotic within 31-60 days of a cardiac development, and past exposure was defined as any patient who had been exposed to the antibiotic within 61-365 days of a cardiac incident. Researchers then compared the use of fluoroquinolon with amoxicillin and azithromycin, two other antibiotics.
The results of the study revealed that patients currently taking fluoroquinolon were most at risk, followed by patients who had recently used the antibiotic. Surprisingly, they observed no increased risk of heart problems among patients in the “past use” group.
The research team believe that, if additional studies confirm their findings, that heart health warnings should be added as a potential side effect of using luoroquinolon. Furthermore, researchers hope that physicians start prescribing different forms of antibiotics more frequently, especially for infections that can be easily treated with any number of antibiotic classes.
The study is published in the Journal of the American College of Cardiology.