The risks and benefits of re-administering Fabrazyme following an anaphylactic or severe allergic reaction should be considered. Extreme care should be exercised, with appropriate medical support measures readily available, if the decision is made to re-administer the product [see Warnings and Precautions (5.4) and Clinical Studies (14) ] .

In clinical trials with Fabrazyme, approximately 50-55% of patients experienced infusion reactions during Fabrazyme administration, some of which were severe [see Warnings and Precautions (5.1) ].  Severe infusion reactions experienced by more than one patient in clinical studies with Fabrazyme included chills, vomiting, hypotension, and paresthesia.  Other infusion reactions included pyrexia, feeling hot or cold, dyspnea, nausea, flushing, headache, fatigue, pruritus, pain in extremity, hypertension, chest pain, throat tightness, abdominal pain, dizziness, tachycardia, nasal congestion, diarrhea, edema peripheral, myalgia, urticaria, bradycardia, and somnolence. 

Most patients in clinical trials were pretreated with acetaminophen.  In patients experiencing infusion reactions, pretreatment with an antipyretic and antihistamine is recommended.  Infusion reactions occurred in some patients after receiving pretreatment with antipyretics, antihistamines, and oral steroids.  Infusion reactions tended to decline in frequency with continued use of Fabrazyme.  However, infusion reactions may still occur despite extended duration of Fabrazyme treatment.  If an infusion reaction occurs, decreasing the infusion rate, temporarily stopping the infusion, and/or administrating additional antipyretics, antihistamines, and/or steroids may ameliorate the symptoms.  If severe infusion reactions occur, immediate discontinuation of the administration of Fabrazyme should be considered, and appropriate medical treatment should be initiated.  Severe reactions are generally managed with administration of antihistamines, corticosteroids, intravenous fluids, and/or oxygen, when clinically indicated.  Because of the potential for severe infusion reactions, appropriate medical support measures should be readily available when Fabrazyme is administered.  Patients who have experienced infusion reactions should be treated with caution when re-administering Fabrazyme.

Patients with advanced Fabry disease may have compromised cardiac function, which may predispose them to a higher risk of severe complications from infusion reactions [see Warnings and Precautions (5.1) and (5.2) ]. Patients with compromised cardiac function should be monitored closely if the decision is made to administer Fabrazyme.

In clinical trials with Fabrazyme, a few patients developed IgE antibodies or skin test reactivity specific to Fabrazyme.  Two of six patients in the re-challenge study discontinued treatment with Fabrazyme prematurely due to recurrent infusion reactions. Four serious infusion reactions occurred in three patients during Fabrazyme infusions, including bronchospasm, urticaria, hypotension, and development of Fabrazyme-specific antibodies.  Other infusion-related reactions occurring in more than one patient during the study included rigors, hypertension, nausea, vomiting, and pruritus.  Physicians should consider tes