Which drug is associated with thrombocytosis?

Which drug is associated with thrombocytosis?

• A. Clozapine
• B. Quetiapine
• C. Risperidone
• D. Olanzapine

Answer: (A)

Thrombocytosis means an elevated platelet count, which isn’t a typical adverse effect used to distinguish these antipsychotics. Among these drugs, clozapine stands out for hematologic toxicity, but the hallmark risk is not an increase in platelets—it’s bone marrow suppression leading to neutropenia/agranulocytosis and often accompanying thrombocytopenia (low platelets). That’s why patients on clozapine require regular blood monitoring (CBC with differential and absolute neutrophil count) and are managed carefully if counts fall. The other medications—quetiapine, risperidone, and olanzapine—do not have as strong a signal for dangerous decreases in blood cells, though they have their own safety profiles. So the key concept to remember is clozapine’s hematologic risk, particularly the potential for low blood cell counts, rather than an increase in platelets.

Thrombocytosis means an elevated platelet count, which isn’t a typical adverse effect used to distinguish these antipsychotics. Among these drugs, clozapine stands out for hematologic toxicity, but the hallmark risk is not an increase in platelets—it’s bone marrow suppression leading to neutropenia/agranulocytosis and often accompanying thrombocytopenia (low platelets). That’s why patients on clozapine require regular blood monitoring (CBC with differential and absolute neutrophil count) and are managed carefully if counts fall. The other medications—quetiapine, risperidone, and olanzapine—do not have as strong a signal for dangerous decreases in blood cells, though they have their own safety profiles. So the key concept to remember is clozapine’s hematologic risk, particularly the potential for low blood cell counts, rather than an increase in platelets.