Last updated on RxList: 7/30/2018
Krystexxa Side Effects Center

Last reviewed on RxList 7/30/2018

Krystexxa (pegloticase) Injection for Intravenous Infusion is an enzyme that metabolizes uric acid into a harmless chemical that is eliminated from the body in urine and is used to treat chronic gout. Krystexxa is usually given after other gout medications have been tried without successful treatment of symptoms. Common side effects of Krystexxa include:

Tell your doctor if you have serious side effects of Krystexxa including

  • chest pain, or
  • flushing (warmth, redness, or tingly feeling)

The recommended dose and regimen of Krystexxa for adult patients is 8 mg (uricase protein) given as an intravenous infusion every two weeks. Krystexxa may interact with other drugs. Tell your doctor all medications and supplements you use. During pregnancy, Krystexxa should be used only if prescribed. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Our Krystexxa (pegloticase) Injection, for Intravenous Infusion Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.


Gout Attack Symptoms, Causes, Treatment, and Diet See Slideshow
Krystexxa Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: 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 side effects may include:

  • allergic reactions;
  • new gout flares;
  • vomiting, constipation;
  • bruising; or
  • sore throat.

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.

Read the entire detailed patient monograph for Krystexxa (Pegloticase Injection)


Gout is a form of arthritis. See Answer
Krystexxa Professional Information


The following serious adverse reactions are discussed in greater detail in other sections of the label:

  • Anaphylaxis [see WARNINGS AND PRECAUTIONS]
  • Infusion Reactions [see WARNINGS AND PRECAUTIONS]
  • G6PD Deficiency Associated Hemolysis and Methemoglobinemia [see WARNINGS AND PRECAUTIONS]
  • Congestive Heart Failure [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

The data described below reflect exposure to KRYSTEXXA in patients with chronic gout refractory to conventional therapy in two replicate randomized, placebo-controlled, double-blind 6-month clinical trials: 85 patients were treated with KRYSTEXXA 8 mg every 2 weeks; 84 patients were treated with KRYSTEXXA 8 mg every 4 weeks; and 43 patients were treated with placebo. These patients were between the ages of 23 and 89 years (average 55 years); 173 patients were male and 39 were female; and 143 patients were White/Caucasian, 27 were Black/African American, 24 were Hispanic/Latino and 18 were all other ethnicities. Common co-morbid conditions among the enrolled patients included hypertension (72%), dyslipidemia (49%), chronic kidney disease (28%), diabetes (24%), coronary artery disease (18%), arrhythmia (16%), and cardiac failure/left ventricular dysfunction (12%).

Because clinical studies are conducted under widely varying and controlled conditions, adverse reaction rates observed in clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug, and may not predict the rates observed in a broader patient population in clinical practice.

The most commonly reported adverse reactions that occurred in greater than or equal to 5% of patients treated with KRYSTEXXA 8 mg every 2 weeks are provided in Table 1.

Table 1. Adverse Reactions Occurring in 5% or More of Patients Treated with KRYSTEXXA Compared to Placebo

Adverse Reaction
(Preferred Term)
8 mg every 2 weeks
Na (%)
N (%)
Gout flare 65 (77%) 35 (81%)
Infusion reaction 22 (26%) 2 (5%)
Nausea 10 (12%) 1 (2%)
Contusionb or Ecchymosisb 9 (11%) 2 (5%)
Nasopharyngitis 6 (7%) 1 (2%)
Constipation 5 (6%) 2 (5%)
Chest Pain 5 (6%) 1 (2%)
Anaphylaxis 4 (5%) 0 (0%)
Vomiting 4 (5%) 1 (2%)
a If the same subject in a given group had more than one occurrence in the same preferred term event category, the subject was counted only once.
b Most did not occur on the day of infusion and could be related to other factors (e.g., concomitant medications relevant to contusion or ecchymosis, insulin dependent diabetes mellitus).


Anti-pegloticase antibodies developed in 92% of patients treated with KRYSTEXXA every 2 weeks, and 28% for placebo. Anti-PEG antibodies were also detected in 42% of patients treated with KRYSTEXXA. High anti-pegloticase antibody titer was associated with a failure to maintain pegloticase-induced normalization of uric acid. The impact of anti-PEG antibodies on patients’ responses to other PEG-containing therapeutics is unknown.

There was a higher incidence of infusion reactions in patients with high anti-pegloticase antibody titer: 53% (16 of 30) in the KRYSTEXXA every 2 weeks group compared to 6% in patients who had undetectable or low antibody titers.

As with all therapeutic proteins, there is a potential for immunogenicity. The observed incidence of antibody positivity in an assay is highly dependent on several factors including assay sensitivity and specificity and assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, the comparison of the incidence of antibodies to pegloticase with the incidence of antibodies to other products may be misleading.

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of KRYSTEXXA. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship.

General disorders and administration site conditions: asthenia, malaise, peripheral swelling

Read the entire FDA prescribing information for Krystexxa (Pegloticase Injection)

© Krystexxa Patient Information is supplied by Cerner Multum, Inc. and Krystexxa Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

Health Solutions From Our Sponsors