Krystexxa is an enzyme that metabolizes uric acid into a harmless chemical that is eliminated from the body in urine. People with gout have too much uric acid in their bodies. Uric acid crystals collect in joints, kidneys, and other organs, and may cause pain, redness and swelling (inflammation).

Krystexxa injection is a prescription medicine used in adults to help reduce the signs and symptoms of gout that are not controlled by other treatments.

Krystexxa is usually given after other gout medications have been tried without successful treatment of symptoms.

You should not receive Krystexxa if you are allergic to pegloticase, or if you have a genetic enzyme deficiency called glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Some drugs can interact with Krystexxa and should not be used at the same time, especially allopurinol (Zyloprim), probenecid (Benemid), or febuxostat (Uloric).

Tell your caregivers right away if you feel itchy, light-headed, short of breath, or have chest discomfort or skin redness during the injection.

You may be given other medications to prevent certain side effects of Krystexxa. You may need to start taking these medications at least a week before you receive your injection. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice. Tell your caregiver right away if you feel itchy, nervous, light-headed, short of breath, or have a fast heartbeat, chest discomfort, or redness of your skin when the medicine is injected into your vein.

Krystexxa is recommended to be given with another prescription medicine called methotrexate. It may also be used alone.

Krystexxa is given as an infusion into a vein, usually once every 2 weeks. A healthcare provider will give you this injection.

This medicine must be given slowly, and the infusion can take at least 2 hours to complete.

You may be given other medications to help prevent serious side effects or an allergic reaction. Your doctor may also recommend other gout medications to use during the first 6 months of treatment with Krystexxa. Keep using all medicines for as long as your doctor has prescribed.

When you first start using Krystexxa, you may have an increase in gout flares.

Your doctor will need to check your progress on a regular basis.

Tell your doctor if your symptoms do not improve after 3 months of treatment.

Usual Adult Dose for Gout:

8 mg every two weeks given as an intravenous infusion, co-administered with weekly methotrexate 15 mg orally. Krystexxa alone may be used in patients for whom methotrexate is contraindicated or not clinically appropriate.

Comment:
-Patients should receive premedications (e.g., antihistamines, corticosteroids) to minimize the risk of anaphylaxis and infusion reactions.

Use: For the treatment of chronic gout in patients who are refractory to conventional therapy (e.g., patients who have failed to normalize serum uric acid and whose signs/symptoms are inadequately controlled with xanthine oxidase inhibitors at the maximum medically appropriate dose or for whom these drugs are contraindicated)

You should not be treated with Krystexxa if you are allergic to pegloticase, or if you have a genetic enzyme deficiency called glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Some medicines can cause unwanted or dangerous effects when used with Krystexxa. Your doctor may change your treatment plan if you also use:

• allopurinol (Zyloprim); or

• febuxostat (Uloric).

Tell your doctor if you have ever had:

• heart problems; or

• high blood pressure.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

Call your doctor for instructions if you miss an appointment for your Krystexxa injection.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have any signs of an allergic reaction to Krystexxa: hives; wheezing, difficult breathing; swelling of your face, lips, tongue, or throat.

Some side effects may occur during the injection. Tell your caregiver if you feel nervous, light-headed, itchy, short of breath, or have fast heartbeats, chest discomfort, or redness of your skin during the injection.

Call your doctor at once if you have:

• chest pain; or

• flushing (warmth, redness, or tingly feeling).

Common Krystexxa side effects may include:

• COVID-19 symptoms such as fever or chills, cough, sore throat, shortness of breath, fatigue, muscle or body aches, headache, loss of taste or smell;

• hives, shortness of breath, chest pain or discomfort, skin redness, or itching;

• joint pain;

• allergic reactions;

• new gout flares;

• nausea, vomiting, constipation; or

• bruising.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may interact with pegloticase, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.