Orladeyo (berotralstat) is a brand-name oral capsule prescribed to help prevent hereditary angioedema (HAE) attacks in adults and some children. As with other drugs, Orladeyo can cause side effects, such as abdominal pain and diarrhea.

Orladeyo can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Orladeyo in clinical trials:

Some of these side effects are discussed in more detail in the “Side effect specifics” section below.

Mild side effects can occur with Orladeyo use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to the Orladeyo prescribing information.

Mild side effects that have been reported with Orladeyo include:

  • back pain
  • GI side effects:
    • vomiting
    • diarrhea
    • abdominal pain
  • GERD
  • fatigue
  • headache
  • flatulence (gas)
  • skin rash

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

An allergic reaction is possible after using Orladeyo. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Orladeyo and want to tell the FDA about it, visit MedWatch.

Orladeyo may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to the drug’s prescribing information.

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

Serious side effects that have been reported include a risk of a heart rhythm problem called QT prolongation.

An allergic reaction is possible after taking Orladeyo. However, this side effect wasn’t reported in the drug’s clinical trials.

To learn more about QT prolongation and allergic reaction, see the “Side effect specifics” section below.

Orladeyo may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How do side effects of Orladeyo compare with those seen with Takhzyro?

These drugs share many side effects, including diarrhea, headache, and skin rash. However, there are some differences because of how each drug is given.

While Orladeyo is an oral tablet that you swallow, lanadelumab-flyo (Takhzyro) is given as a subcutaneous injection. As such, it can cause injection site reactions such as pain, bruising, or skin discoloration. Orladeyo doesn’t cause this side effect. (The reason “-flyo” appears at the end of the drug’s name is to show that it’s distinct from similar medications that may be created in the future.)

Orladeyo and Takhzyro are both prescribed to help prevent attacks of hereditary angioedema (HAE). Talk with your doctor if you have questions about how the side effects of these medications compare. Your doctor will prescribe the drug that’s right for you.

Can Orladeyo cause long-term side effects?

It’s unlikely, as long-term side effects weren’t reported in clinical trials of Orladeyo. Most of this medication’s side effects are expected to be temporary. They’ll likely go away shortly after you start or stop treatment with the drug. However, the length of time Orladeyo’s side effects last will vary between people.

To learn more, see the “Orladeyo side effects” section above. If you’d like more information about possible long-term side effects of the drug, talk with your doctor or pharmacist.

Learn more about some of the side effects that Orladeyo may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Orladeyo.

GI side effects

People who took Orladeyo in clinical trials commonly reported GI side effects, including abdominal pain, vomiting, and diarrhea. Abdominal pain was the most common side effect of Orladeyo in these trials.

These side effects generally occurred soon after starting treatment with the drug. They were temporary and typically went away on their own.

What you can do

If you experience GI side effects, your doctor may be able to recommend ways to relieve them. Be sure to tell your doctor if these side effects don’t go away or if they become severe. Your doctor may prescribe a lower dose of Orladeyo to decrease the GI side effects.

Risk of QT prolongation

It’s possible that Orladeyo can cause a heart rhythm problem called QT prolongation. It can be serious and, in some cases, life threatening. This side effect was rare in the drug’s clinical trials.

Symptoms of QT prolongation may include:

QT prolongation was reported only with dosages higher than the recommended dosage of 150 milligrams (mg) per day.

What you can do

It’s important to take Orladeyo exactly as prescribed by your doctor. Taking additional doses of the drug or taking more than the recommended dose of Orladeyo increases your risk of QT prolongation. For this reason, doctors don’t recommend doses higher than 150 mg. To learn about Orladeyo and dosage, see this article.

If you experience any of the symptoms listed above, talk with your doctor right away.

If you have questions about your personal risk of QT prolongation, talk with your doctor before starting Orladeyo.

Allergic reaction

As with most drugs, Orladeyo can cause an allergic reaction in some people. However, this side effect wasn’t reported in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Orladeyo. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Orladeyo. This drug may not be the right treatment option for you if you have certain medical conditions or other factors that affect your health. These include:

Kidney problems: It’s not known whether Orladeyo is safe to take if you have severe kidney problems. This includes chronic kidney disease, especially if you’re receiving dialysis. Before starting Orladeyo, tell your doctor if you are receiving dialysis or have severe kidney problems. Your doctor may recommend a different treatment option for you.

Liver problems: Tell your doctor if you have liver problems before taking Orladeyo. You may have an increased risk of side effects with the drug. Depending on the severity of your liver condition, your doctor may recommend taking a lower dose of Orladeyo. Doing so may reduce your risk of side effects.

Allergic reaction: If you’ve had an allergic reaction to Orladeyo or any of its ingredients, your doctor will likely not prescribe Orladeyo. Ask your doctor what other medications may be better options for you.

Pregnancy or breastfeeding: It’s not known whether Orladeyo is safe to take if you’re pregnant or breastfeeding your child. Talk with your doctor before starting Orladeyo if you are pregnant, planning to become pregnant, or breastfeeding. They can discuss the risks and benefits of Orladeyo treatment with you.

Alcohol consumption: There’s no known interaction between Orladeyo and alcohol. However, drinking alcohol may increase your risk of side effects of Orladeyo, such as vomiting or diarrhea. If you drink alcohol, talk with your doctor. They may be able to advise on an amount that is safe to consume while taking Orladeyo.

Most side effects that Orladeyo can cause are mild and go away as your body adjusts to the drug. Serious side effects are rare. If you have symptoms that are bothersome or become serious, talk with your doctor.

If you’d like to learn more about Orladeyo, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

  • More information about Orladeyo: For details about other aspects of Orladeyo, refer to this article.
  • Cost: If you’d like to learn about Orladeyo and cost, see this article.
  • Dosage: For information about the dosage of Orladeyo, view this article.
  • A look at HAE: For details about your condition, see these articles about HAE and HAE episodes.

Disclaimer: Medical News Today 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.