Key takeaways

  • Krystexxa (pegloticase) is a prescription drug approved to treat a certain type of gout in adults.
  • This drug is given as an intravenous (IV) infusion by a doctor or another healthcare professional in a hospital, clinic, or infusion center. Infusions typically last about 2 hours.
  • Krystexxa has boxed warnings for the risks of severe allergic reactions and infusion reactions. It also has a boxed warning for life threatening blood cell problems in people with a G6PD deficiency.

Specifically, Krystexxa is used in adults to treat chronic (long-term) gout when other treatments haven’t worked.

To learn more about Krystexxa’s uses, see the “Uses for Krystexxa” section.

Krystexxa basics

Krystexxa contains the active ingredient pegloticase. It belongs to a group of drugs called PEGylated uric acid-specific enzymes.

Krystexxa is a brand-name medication. A generic version of the drug isn’t currently available.

Krystexxa has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Krystexxa precautions” section.

Krystexxa’s indication (the condition it’s used to treat) is chronic refractory gout in adults. (Refractory means other treatments have been tried for this condition, but either didn’t work or eventually stopped working.)

Krystexxa may be prescribed on its own or with other medications (such as oral methotrexate) and folic acid or folinic acid supplements.

Gout is a condition in which your blood contains too much uric acid. This is a waste product that forms crystals in certain joints, especially the one at the base of your big toe. It can also form crystals in other joints, such as your elbows, wrists, fingers, knees, ankles, and feet.

Gout crystals irritate the affected joint, causing severe pain and inflammation. This is called a gout attack or gout flare-up. Symptoms include skin discoloration over the joint, heat, stiffness, swelling, and sudden, intense pain.

How it works

The active ingredient in Krystexxa is an enzyme called pegloticase. Its mechanism of action (how it works) to treat gout is by breaking down uric acid that collects in certain joints and organs. Uric acid that’s been broken down is easier for your body to eliminate via your kidneys and urine, thus easing the pain and swelling from gout.

Like most drugs, Krystexxa may cause mild to serious side effects. The following lists contain some of the more common side effects Krystexxa may cause, but they don’t include all possible side effects.

Keep in mind that the side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Krystexxa. They can also suggest ways to help reduce or manage them.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect during treatment with Krystexxa and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Mild side effects

Here’s a list of some of the mild side effects Krystexxa can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read the drug manufacturer’s prescribing information.

Mild side effects of Krystexxa that have been reported include:

  • fatigue
  • limb pain
  • joint pain
  • nausea
  • COVID-19 (while not a side effect of the drug itself, Krystexxa may make your body more vulnerable to viral infections)

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Krystexxa can occur, but they aren’t common. If you have serious side effects from this medication, call your doctor right away. If you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Krystexxa that have been reported include:

For more information about side effects related to boxed warnings, see the “Krystexxa precautions” section.

Allergic reaction

For some people, Krystexxa can cause an allergic reaction, including a severe allergic reaction called anaphylaxis. Krystexxa has a boxed warning for anaphylaxis. See the “Krystexxa precautions” section for more information.

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 and can determine whether you should continue Krystexxa treatment.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty 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 Krystexxa, they may have you switch to a different treatment.

The Krystexxa dosage your doctor prescribes will depend on several factors. These include the severity of your condition, your age, and other medical conditions you may have.

The following information describes dosages that are commonly used or recommended. But your doctor will determine the best dosage to fit your needs.

Forms and strength

Krystexxa is available as a liquid solution that’s given as an intravenous (IV) infusion (an injection into a vein given over time). It comes in two forms, each of which contains 8 milligrams (mg) of pegloticase. These are:

  • ready-to-use 8 mg per 50 milliliters (0.16 mg per mL) in a single-dose vial
  • to-be-diluted 8 mg per mL in a single-dose vial

Recommended dosage for gout

For the treatment of gout, your doctor will likely prescribe 8 mg every 2 weeks. They may also prescribe 15 mg of oral methotrexate and folic acid or folinic acid supplements. You’ll begin taking these 4 weeks before starting Kyrstexxa treatment and will take them once per week during treatment.

Krystexxa can also be given alone (without methotrexate and folic or folinic acid) if these other products aren’t suitable for you.

How it’s given

Krystexxa comes as a liquid solution that’s given as an IV infusion by a doctor or another healthcare professional. You’ll receive these infusions at a hospital, clinic, or infusion center.

Your doctor will monitor you for infusion reactions or allergic reactions during and after your infusion, since these reactions can become serious. Krystexxa has boxed warnings for these reactions. See the “Krystexxa precautions” section for more details.

To help prevent these reactions, your doctor will give you medications such as an antihistamine and a corticosteroid before your infusion.

Your doctor will explain how Krystexxa will be given to you. They’ll also explain how much you’ll be given and how often.

About receiving Krystexxa

The following are some common questions about receiving Krystexxa treatment.

  • How long does each infusion last? Krystexxa infusions typically take about 2 hours or longer.
  • How long does it take Krystexxa to start working? Krystexxa starts to work within the first day of treatment.
  • Is Krystexxa a long-term treatment? It depends on how your body responds to Krystexxa. If your uric acid level goes above a certain amount more than once during treatment, this could indicate the drug’s no longer working. It could also increase your risk of side effects. In this case, your doctor may have you stop Krystexxa treatment.

Before starting Krystexxa, talk with your doctor. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, or supplements you use. Sharing this information can help you avoid potential interactions.

Krystexxa can interact with the following drugs:

  • medications that contain a PEG molecule
  • methotrexate, which your doctor may prescribe along with Krystexxa (see the “Uses for Krystexxa” section for details)
  • urate-lowering medications

This list does not contain all substances that may interact with Krystexxa. If you have questions about interactions that may affect you, ask your doctor or pharmacist.

Krystexxa and alcohol

Alcohol isn’t known to interact with Krystexxa. But it may be unsafe to consume alcohol if you have gout, which Krystexxa is used to treat. Because of this, your doctor may recommend that you limit the amount of alcohol you drink.

If you have questions about how much alcohol is safe to drink during treatment with Krystexxa, talk with your doctor.

Whether you have health insurance or not, cost may be a factor when you’re considering this treatment option. What you’ll pay for Krystexxa may depend on several things, such as your treatment plan, your insurance plan, your location, and the pharmacy that’s used.

If you need help paying for Krystexxa or understanding your insurance coverage, a program called Amgen By Your Side is available. This program can help determine your cost assistance options, including whether you qualify for the Amgen Commercial Co-Pay Program. For more information and to find out whether you’re eligible for support, visit the program website or call 844-469-4297.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist.

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The following is important information to consider and discuss with your doctor before starting treatment with Krystexxa.

Pregnancy and Krystexxa

It’s not known whether Krystexxa is safe during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before starting treatment with this medication.

Krystexxa and breastfeeding

It’s not known whether Krystexxa is safe while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before starting this drug.

This section describes the warnings and precautions for Krystexxa.

FDA warnings

Krystexxa has boxed warnings about the risk of severe allergic reaction and infusion reaction. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous. The following are boxed warnings for Krystexxa.

Infusion reactions

Infusion reactions are common with Krystexxa treatment, especially when it’s given without methotrexate. Krystexxa is given in a hospital, clinic, or infusion center so a healthcare professional can monitor you for infusion reactions during and after your treatment.

If a reaction occurs, they may slow your infusion or stop and restart it at a lower rate. Be sure to tell them if you experience any of the following symptoms:

  • chest pain or discomfort
  • difficulty breathing
  • hives
  • itchy skin
  • skin discoloration

Symptoms can also develop after you’ve left the hospital, clinic, or infusion center. If you have a medical emergency, call 911 or your local emergency number immediately.

Risk of severe allergic reaction

Anaphylaxis is a serious and life threatening allergic reaction that can happen during Krystexxa infusions, which is why they’re given in a hospital, clinic, or infusion center.

Symptoms of anaphylaxis include:

To lower your risk of anaphylaxis, your doctor or another healthcare professional will give you medications such as an antihistamine and a corticosteroid before your infusion. They’ll also monitor you for symptoms during and after the infusion. Tell them right away if you experience any symptoms of anaphylaxis.

Symptoms can also develop after you’ve left the hospital, clinic, or infusion center. If you have a medical emergency, call 911 or your local emergency number immediately.

Blood cell problems in people with a G6PD deficiency

If you have a glucose-6-phosphate dehydrogenase (G6PD) deficiency, your doctor won’t prescribe Krystexxa for you. With this condition, you don’t have enough of an enzyme called G6PD, which regulates chemical reactions in your body and helps keep red blood cells healthy.

Life threatening blood cell problems have been reported in people with G6PD deficiency who were given Krystexxa. These include methemoglobinemia (the buildup of an atypical form of hemoglobin in your blood) and hemolysis (the breakdown of red blood cells).

Before you begin Krystexxa treatment, your doctor will order tests to learn whether you have G6PD deficiency.

Other precautions

Before starting Krystexxa, discuss your health history with your doctor. This treatment may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Note: For more information about the potential negative effects of Krystexxa, see the “Side effects of Krystexxa” section.

Other drugs that can treat gout are available.

The following drugs are similar to Krystexxa:

If you’d like to explore an alternative to Krystexxa, talk with your doctor. They can tell you about other medications that might work well for you.

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.