WBR0477

Author	[[PageAuthor::Yazan Daaboul, M.D., (Reviewed by Yazan Daaboul, M.D. and Alison Leibowitz [1])]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry, MainCategory::Pharmacology
Sub Category	SubCategory::Hematology
Prompt	[[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?]]
Answer A	AnswerA::Liver transaminases levels
Answer A Explanation	[[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.]]
Answer B	AnswerB::Serum creatinine level
Answer B Explanation	[[AnswerBExp::Creatinine testing is not routinely performed upon clozapine administration.]]
Answer C	AnswerC::Absolute neutrophil count
Answer C Explanation	[[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.]]
Answer D	AnswerD::Electrolyte panel
Answer D Explanation	[[AnswerDExp::Electrolyte panel testing is not routinely performed upon clozapine administration.]]
Answer E	AnswerE::Hemoglobin level
Answer E Explanation	[[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.]]
Right Answer	RightAnswer::C
Explanation	[[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 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. Educational Objective: 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. First Aid 2014 page 253]]
Approved	Approved::Yes
Keyword	WBRKeyword::Schizophrenia, WBRKeyword::Leukopenia, WBRKeyword::Granulocytopenia, WBRKeyword::Agranulocytosis, WBRKeyword::Adverse drug event, WBRKeyword::Adverse drug reaction, WBRKeyword::Side effect, WBRKeyword::Clozapine, WBRKeyword::WBC, WBRKeyword::ANC, WBRKeyword::Absolute neutrophil count, WBRKeyword::Screening, WBRKeyword::Antipsychotics
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