You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Brand", "UnapprovedDrug", "Drug", "DrugGroup"].

Please return the output as a JSON object of the format: {"Brand" : ["Aspirin", ...], "DrugGroup": ["Salicyclate", ...], "Drug": ["Phenobarbital", ...], "UnapprovedDrug": ["Heroin", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

No formal drug interaction studies have been performed with ZEVALIN. Due to the frequent occurrence of severe and prolonged thrombocytopenia, the potential benefits of medications which interfere with platelet function and/or anticoagulation should be weighed against the potential increased risks of bleeding and hemorrhage. Patients receiving medications that interfere with platelet function or coagulation should have more frequent laboratory monitoring for thrombocytopenia. In addition, the transfusion practices for such patients may need to be modified given the increased risk of bleeding. Patients in clinical studies were prohibited from receiving growth factor treatment for 2 weeks prior to the ZEVALIN therapeutic regimen as well as for 2 weeks following completion of the regimen.
{"Brand": ["ZEVALIN"], "Drug": [], "DrugGroup": [], "UnapprovedDrug": []}