For many doctors, the use of the anti-fungal medication terbinafine has been a game-changer in treating fungal issues. However, it can present a potential risk of liver damage when taken orally.

This article provides information about terbinafine’s use and possible side effects, as well as ways to lower that risk and protect your liver health.

It’s important to always discuss any medication concerns or general questions with your healthcare team.

Terbinafine is an antifungal medication used to treat certain types of fungal and yeast infections. It can be purchased in a cream, gel, or spray to help treat conditions like ringworm, jock itch, and athlete’s foot. A pill version can be prescribed to treat fungal nail infections.

The Food and Drug Administration (FDA) approved it for use as a topical cream in 1999 and for oral use in 1992. It is commonly sold under the brand names Lamisil and Terbinex.

Like many medications, after terbinafine is ingested, the liver metabolizes it, and the kidneys excrete it. So it’s very important that these organs are properly functioning.

There’s long been some concern about terbinafine’s potential for negative effects on the liver. Research looking into this goes back to before the United States approved the oral version of the drug.

In fact, a study dating back to 1996 evaluated use of the medication in 9,879 UK patients — and while there was a risk for adverse effects, the study found liver problems in only 0.1% of study participants.

That study and other more recent research indicates that preexisting liver conditions may play a role in why a very small number of individuals experience liver issues while on terbinafine. There’s also evidence suggesting that some individuals are more susceptible based on a genetic link to liver issues when taking terbinafine.

Because of potential risks, manufacturers have continually advised against prescribing terbinafine tablets for patients with liver disease.

It’s true that liver injury is a potential side effect of terbinafine. But liver failure does not commonly occur.

In fact, liver injury from terbinafine use only occurs in an estimated 1 in 50,000 to 120,000 prescriptions.

If liver injury does occur, it usually happens within the first 6 weeks of taking terbinafine. (It’s important to know that in the previously mentioned research, the probability of having elevated liver enzyme levels requiring stopping treatment was shown to increase when terbinafine treatments lasted longer than 8 weeks compared with those only taking it for only 2 to 6 weeks. This is one reason why your doctor may request blood testing if you need to take terbinafine for a prolonged period.)

In most cases, patients reporting symptoms leads to discovering liver damage. Symptoms can include:

In some cases, no symptoms are initially present. In these cases, blood testing may help identify terbinafine-related liver problems. (Doctors can use liver function blood tests to determine if there are elevated liver enzyme levels in the blood.)

Before taking terbinafine, it’s important to discuss your health history and any prior drug reactions with your doctor. Your healthcare team may also have blood drawn to check your liver health before prescribing terbinafine.

Once you start taking terbinafine, it’s important stay alert to symptoms like jaundice, nausea, fatigue, and itching that may indicate liver problems. When you know what to look for, you can — and are more likely to — notify your doctor quickly. Early detection can help prevent serious liver problems!

While it’s generally not necessary to undergo frequent laboratory monitoring, your doctor may suggest it, especially if you’ll be on terbinafine for an extended period of time.

If terbinafine use is damaging your liver, your doctor may simply have you stop taking the medication. Frequently, liver health improves in cases of acute damage within several months of discontinuing terbinafine use.

In cases where severe liver damage occurs, a liver transplant may be necessary.

Terbinafine is an oral and topical antifungal medication commonly sold under the brand names Lamisil and Terbinex. The oral medication form may cause liver damage. But there’s only a small likelihood the oral medication will cause liver damage.

Before starting Terbinafine, talk with your doctor about any questions or concerns you may have. They can also answer any questions you may have about symptoms of liver damage.