CLOZARIL is an antipsychotic (a family of drugs used to treat patients suffering from schizophrenia and other mental illnesses). CLOZARIL requires that people-and their healthcare professionals- make a commitment to this therapy. Although it is extremely rare, a blood disorder called agranulocytosis has been associated with CLOZARIL. In this disorder, white blood cells are not made-or not enough of them are made. This reduces the body's resistance to infection. Even though the risk of agranulocytosis is low, people who take CLOZARIL must have their blood tested on a regular basis. Therefore, people taking CLOZARIL may need extra encouragement and support from their friends and healthcare professionals.