Why is regular CBC monitoring important for clozapine therapy, and what is the typical schedule?

• A. To monitor liver enzymes; weekly
• B. To detect agranulocytosis; weekly for initial months, then every 2 weeks to monthly
• C. To track blood glucose; monthly
• D. To measure potassium; yearly

Answer: (B)

Regular CBC monitoring is essential to detect agranulocytosis, a dangerous drop in white blood cells that can occur with clozapine. Catching this early lets clinicians stop the medication and treat infections before they become life-threatening. Because the risk is highest when starting treatment, counts are checked frequently at first. The typical pattern is weekly CBCs during the initial months, then every two weeks as the patient continues, and finally monthly if counts remain stable. This schedule provides steady protection while gradually reducing testing as safety is established. Baseline counts are needed before starting, and any significant drop leads to holding or stopping clozapine and rechecking counts.