View source for WBR0477

 {{WBRQuestion
|QuestionAuthor= {{YD}}, (Reviewed by  {{YD}} and  {{AJL}})
|ExamType=USMLE Step 1
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=Hematology
|Prompt=A 24-year-old man is admitted to the hospital for auditory hallucinations and delusions. His older brother reports that the patient is diagnosed with treatment-resistant schizophrenia and has been administered several medications for the past 4 years without improvement. The physician then decides to start the patient on clozapine therapy. Which of the following lab tests should be routinely performed to monitor for clozapine-induced adverse events?
|Explanation=[[Clozapine]] is a second generation antipsychotic medication that has demonstrated significant efficacy for the treatment of schizophrenia and reduction in the frequency of relapses. [[Clozapine]] is reserved for refractory cases of schizophrenia due to its association with [[agranulocytosis]] in approximately 1% of cases. Periodic complete blood count (CBC) is usually performed in schizophrenic patients who are administered [[clozapine]] to monitor for any signs of leokopenia, granulocytopenia, and [[agranulocytosis]] by measurement of white blood cells (WBC) count and absolute neutrophil count (ANC). With initiation of clozapine therapy, WBC and ANC are monitored weekly for the first 6 months, then every other week for the next 6 months, then every 4 weeks thereafter.
|AnswerA=Serum ALT level
|AnswerAExp=Although clozapine has been associated with hepatotoxicty, screening for hepatotoxicity by liver transaminase testing is currently not recommended following initiation of [[clozapine]] administration. Approximately 30 - 50% of patients have an asymptomatic elevation in liver transaminases. Fulminant hepatic failure has been reported in patients administered clozapine in rare instances.
|AnswerB=Serum creatinine level
|AnswerBExp=Creatinine testing is not routinely performed upon [[clozapine]] administration.
|AnswerC=Absolute neutrophil count
|AnswerCExp=Due to the risk of [[agranulocytosis]], white blood cell (WBC) count and absolute neutrophil count (ANC) must be routinely performed for patients administered [[clozapine]].
|AnswerD=Electrolyte panel
|AnswerDExp=Electrolyte panel testing is not routinely performed upon [[clozapine]] administration.
|AnswerE=Hemoglobin level
|AnswerEExp=Generally, a complete blood count (CBC) is obtained for patients who are administered clozapine to monitor for leokopenia, granulocytopenia, and agranulocytosis by measurement of WBC and ANC levels. Although a CBC gives information about the hemoglobin levels, neither anemia nor polycythemia is the main concern following clozapine administration.
|EducationalObjectives=[[Clozapine]] is a second generation antipsychotic medication that is highly effective in the treatment of symptoms of schizophrenia. [[Clozapine]] is reserved for treatment-resistant cases of schizophrenia due to its association with [[agranulocytosis]] in approximately 1% of cases.
|References=Chang A, Krygier DS, et al. Clozapine-induced fatal fulminant hepatic failure: a case report. Can J Gastroenterol. 2009;23(5):376-8.<br>
First Aid 2014 page 253
|RightAnswer=C
|WBRKeyword=Schizophrenia, Leukopenia, Granulocytopenia, Agranulocytosis, Adverse drug event, Adverse drug reaction, Side effect, Clozapine, WBC, ANC, Absolute neutrophil count, Screening, Antipsychotics
|Approved=Yes
}}