Antibiotics and Liver Injury: What’s the Relationship and Risk?

In rare cases, common drugs such as Z-Paks, prescribed to fight illnesses, can harm the liver. A U-M patient and liver specialist explain.

7:00 AM

Author | Michigan Medicine

Eric Barth walking his dog after recovering from a drug-induced liver injury from Z-Paks

In 2009, Eric Barth arrived at an emergency department in Kalamazoo, Michigan, with the typical symptoms of pneumonia.

Physicians there prescribed the 45-year-old patient with a high dose of azithromycin, commonly known as a "Z-Pak," which he took as instructed for a five-day span.

SEE ALSO: Why Herbal and Dietary Supplements Cause Some Doctors Concern

Azithromycin, a commonly prescribed antibiotic, has proven effective for the treatment of bacterial infections. As expected, it worked for Barth almost immediately.

About two weeks later, though, he began to experience troubling side effects that included upper abdominal pain, nausea and dark-colored urine.

"I started feeling more ill every day," recalls Barth, now 52. "It's like what the fast-talking voice-over says in the TV (pharmaceutical) commercials: 'Be careful of a yellowing of the skin and eyes, as this can be the sign of an untoward liver reaction.'

"It turns out, in my case, that's what it was."

What might have been more unexpected is that the medication intended to help him is likely what caused the malady.

Weighing efficacy and risk

A visit to Barth's primary care physician, which included blood tests, found that his liver values were very high.

That suggests a hallmark symptom of drug-induced liver injury (DILI), says Robert J. Fontana, M.D., a hepatologist and Medical Director of the Liver Transplant Program at University of Michigan Health System.

SEE ALSO: Which Over-the-Counter Pain Medication Is Best?

Azithromycin can lead to DILI in a relatively small subset of patients, according to research performed in Fontana's clinic. The frequency of these reactions varies between 1 in 10,000 patients taking the drug to less than 1 in a million. And it is one of many on a long list of antibiotics associated with liver-related adverse events.

Barth was referred to Fontana and ultimately diagnosed with cholestatic hepatitis.

He has been receiving treatment for the condition, which is now chronic, with an immunosuppressant for the past six years. His condition is in remission, says Fontana, who has studied Barth's condition as part of his ongoing research funded by the National Institutes of Health since 2003 called the Drug Induced Liver Injury Network.

According to Fontana, more than 1,600 patients have been enrolled into the study, and the DILIN team is now beginning to identify genetic markers in some patients who develop liver reactions. Going forward, it is hoped that this line of research will lead to a reduction in adverse liver events from a multitude of drugs and herbal and dietary supplements, which are also increasingly associated with potentially severe liver reactions in some people.

Thanks to Fontana's care and encouragement, Barth has been able to resume a normal life.

"There was always a real sense of reassurance from him that I would get better," Barth says. "And that was a huge help in my recovery."

Doctors, meanwhile, shouldn't avoid prescribing antibiotics like azithromycin because of the risks, Fontana says.

"These drugs have been proven safe and effective for the vast majority of patients," Fontana says. "However, as physicians, we should consider the possibility of liver damage in some patients and warn all patients of these risks … (and) also advise them of how to recognize the symptoms and what to do should they arise."

More Articles About: Health Management Medication Interactions Liver Disease Pharmacy
Health Lab word mark overlaying blue cells
Health Lab

Explore a variety of healthcare news & stories by visiting the Health Lab home page for more articles.

Media Contact Public Relations

Department of Communication at Michigan Medicine

[email protected]


Stay Informed

Want top health & research news weekly? Sign up for Health Lab’s newsletters today!

Featured News & Stories cannabis leaf sketched blue
Health Lab
1 in 8 older adults use cannabis products, suggesting need to screen for risks
The Michigan Medicine finding suggest a need for more education and screening of older adults for cannabis-related risks.
maps purple and blue
Health Lab
Real-time opioid overdose data improves safety response from community
To improve coordinated community response to opioid overdoses, University of Michigan researchers are placing near-real time data in the hands of public health and safety officers. The Michigan System for Opioid Overdose Surveillance, was created in 2016 in response to the opioid crisis through a partnership between the University of Michigan Injury Prevention Center and the Michigan High Intensity Drug Trafficking Areas.
three pharmacists smiling
Health Lab
An innovative pharmacy service for pain management
An innovative service at Michigan Medicine offers pain management support for patients and care teams
wheelchair walker image
Health Lab
Spread of drug resistant bacteria linked to patient hand contamination and antibiotic use within nursing homes
A Michigan Medicine research team seeks to identify characteristics of patients within nursing homes, as well as the nursing home environment itself, that are associated with contamination by vancomycin-resistant enterococci.
Multicolored pill bars graph chart
Health Lab
Dental opioid prescriptions still declining, but not as quickly as pre-pandemic
Dental pain treatment with opioid painkillers like Oxycontin and Oxycodone declined before and during the pandemic but the rate of decline slowed after 2020.
cells in green and purple and black background under microscope
Health Lab
Tiny model organs detect liver toxicity of new drugs
A University of Michigan-led study provided evidence of the efficacy of a new drug-induced liver injury screening platform using human liver organoids, or tiny 3D models of organs developed from patients’ stem cells that grow in petri dishes.