Zepatier (elbasvir/grazoprevir) is a prescription oral tablet used to treat chronic hepatitis C in adults and certain children. Zepatier can cause side effects that range from mild to serious, such as headache and fatigue.

Some people, not everyone, may experience mild to serious side effects during their Zepatier treatment. Examples of the drug’s commonly reported side effects include:

Common side effects of Zepatier when also using ribavirin include:

  • skin rash
  • shortness of breath
  • fatigue
  • headache
  • anemia (low level of red blood cells)

If you have kidney problems and are taking Zepatier, you may be more likely to experience nausea, headaches, or fatigue.

Mild side effects have been reported with Zepatier. These include:

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop taking Zepatier unless your doctor recommends it.

Zepatier may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

* To learn more about this side effect, see the “Side effects explained” section below.
† An allergic reaction is possible after taking Zepatier, but this side effect was only reported after the FDA approved Zepatier for public use.

Serious side effects have been reported with Zepatier. These include:

If you develop serious side effects while taking Zepatier, call your doctor right away. If the side effects seem life threatening or you think you have a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.
† An allergic reaction is possible after taking Zepatier, but this side effect was only reported after the FDA approved Zepatier for public use.

Note: After the FDA approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Zepatier, visit MedWatch.

Get answers to some frequently asked questions about Zepatier’s side effects.

Does Zepatier cause long-term side effects?

It’s possible. Long-term side effects include those that may start at any time you’re taking a drug, even if you’ve taken it for a long time. They also include side effects that may not go away, even after you stop taking the drug.

Examples of long-term side effects reported in Zepatier’s studies include:

According to reports made after Zepatier became available, some people developed severe liver problems. In some cases, these problems were fatal. These liver problems affected people with healthy livers as well as those who already had liver issues such as cirrhosis.

Because of this, your doctor will check your liver function before you start Zepatier treatment and after 8 and 12 weeks of treatment. If you have cirrhosis (scarring of the liver) or advanced liver problems, you might need these tests done more often.

Side effects of liver problems can include:

  • jaundice (yellowing of your skin or the whites of your eyes)
  • abdominal pain and swelling
  • confusion
  • nausea or vomiting

If you experience any of these symptoms, stop taking Zepatier and call your doctor right away.

If you’re concerned about long-term side effects from Zepatier, talk with your doctor or pharmacist.

How do side effects of Zepatier compare with those seen with Harvoni?

Zepatier and ledipasvir/sofosbuvir (Harvoni) can cause similar side effects. Examples of side effects that can occur with both drugs include:

Each drug can cause additional side effects as well. To learn more about how side effects of these drugs compare, talk with your doctor or pharmacist.

* To learn more about this side effect, see the “Side effects explained” section below.

Learn more about some of the side effects Zepatier may cause.

Risk of hepatitis B reactivation in certain people

Zepatier has a boxed warning for the risk of hepatitis B reactivation in certain people. This was an uncommon side effect reported in studies of the drug.

If you’ve had hepatitis B before, taking Zepatier could cause it to reactivate (flare up). If hepatitis B reactivates, it can cause serious liver issues, such as liver failure, and can even be fatal.

Reactivation of hepatitis B can cause symptoms such as:

  • jaundice
  • abdominal pain or swelling
  • dark-colored urine
  • nausea and vomiting
  • reduced appetite
  • pale-colored stool
  • fever
  • weakness and fatigue

Your risk of hepatitis B reactivation with Zepatier may be higher if you:

  • have a weakened immune system
  • are receiving cancer treatment
  • take drugs that suppress your immune system

What might help

If you’ve had hepatitis B before, talk with your doctor before starting Zepatier treatment. They’ll test you for hepatitis B before you start treatment. If the test shows you have hepatitis B, your doctor will likely want to treat it before prescribing Zepatier. They may also monitor you more closely during your Zepatier treatment.

Increased liver enzymes

Zepatier can cause increased liver enzymes, which may be a sign of liver damage.

Increased liver enzymes were a common side effect reported in studies of Zepatier. In most people, increased liver enzymes may not cause any symptoms. But some people may experience symptoms such as:

  • nausea and vomiting
  • abdominal pain and swelling
  • dark-colored urine
  • weakness and fatigue
  • jaundice
  • pale-colored stool
  • reduced appetite

Certain people may have a higher risk of increased liver enzymes with Zepatier, including those who:

  • are of Asian descent
  • are female*
  • are age 65 years or older
  • have liver disease

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

What might help

If you think you may have a higher risk of elevated liver enzymes with Zepatier, talk with your doctor or pharmacist. Your doctor can schedule blood tests to check your liver function during your Zepatier treatment. If you take other medications, your doctor or pharmacist can check whether they may increase your risk of elevated liver enzymes.

Allergic reaction

Like most drugs, Zepatier can cause an allergic reaction in some people. However, this side effect was only reported after the FDA approved Zepatier for public use.

Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin (usually in your eyelids, lips, hands, or feet)
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an antihistamine you swallow, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Zepatier, they’ll decide if you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Zepatier, they may have you switch to a different treatment.

Keeping track of side effects

During your Zepatier treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how Zepatier affects you. They can then use this information to adjust your treatment plan if needed.

Below is important information you should consider before taking Zepatier.

Boxed warning: Risk of hepatitis B reactivation in certain people

Zepatier has a boxed warning for the risk of hepatitis B reactivation in certain people. A boxed warning is the most serious warning from the FDA.

To learn more, see the “Side effects explained” section above.

Other warnings

Zepatier can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Zepatier is a good treatment option for you.

Talk with your doctor about your health history before you take Zepatier. Be sure to tell them if you:

Alcohol and Zepatier

There are no known interactions between alcohol and Zepatier.

However, consuming too much alcohol can cause liver problems. Zepatier may also cause liver problems. So drinking too much while taking Zepatier may increase your risk of liver problems.

If you have questions about consuming alcohol during your Zepatier treatment, talk with your doctor or pharmacist.

Pregnancy and breastfeeding with Zepatier

Zepatier is usually prescribed for someone who’s pregnant or breastfeeding only if the benefits of treatment outweigh the potential risks.

Pregnancy

It’s not known whether it’s safe to take Zepatier during pregnancy.

If you’re able to become pregnant, your doctor may recommend using a form of birth control throughout your Zepatier treatment.

If you’re pregnant or planning a pregnancy, talk with your doctor before taking Zepatier.

Breastfeeding

It isn’t known whether Zepatier is safe to take while breastfeeding. It’s unknown whether the drug passes into breast milk and, if so, how it could affect a breastfed child.

If you’re breastfeeding or planning to do so, talk with your doctor before starting Zepatier treatment.

Like most drugs, Zepatier can cause a number of side effects that range from mild to serious. However, most are temporary and go away after a few days to weeks. If you have questions about side effects that Zepatier can cause, talk with your doctor.

Examples of questions you may want to ask include:

  • Which side effects should I report to you right away?
  • How likely am I to have side effects from Zepatier?
  • Can what I eat or drink make Zepatier’s side effects worse?

To learn more about Zepatier, see this article.

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.