Pegloticase may rarely cause a serious allergic reaction. This may occur during or after the infusion of the medication. Your doctor will check your blood before each treatment and monitor you closely during and after infusion. Your doctor should prescribe other medications (such as antihistamines, corticosteroids) to help prevent an allergic reaction. However, serious allergic reactions may still occur in a few patients. Get medical help right away if you develop any signs of an allergic reaction, such as rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing, chest discomfort/pain.

Do not use this medication if you have a certain metabolic disorder called glucose-6-phosphate dehydrogenase (G6PD) deficiency because it can severely damage your red blood cells leading to anemia (hemolysis). If you are of African, Mediterranean, or Southern Asian descent, you may be at higher risk for G6PD deficiency and should be tested to see if you have this condition before starting this medication.