FDA changes clozapine monitoring guidelines: Implications for worldwide practice

US FDA decision to change their clozapine monitoring guidelines in 2015 for the first time. The changes proposed are as follows: lowering the neutrophil count before ceasing clozapine from 1.5 to 1.0 × 10⁹/l, allowing the potential for re-challenge following severe neutropenia (<1.0 × 10⁹/l) and allowing those with benign ethnic neutropenia the opportunity to be commenced on clozapine. These changes will allow a greater number of patients with schizophrenia in USA to be continued on clozapine. In our correspondence we summarize the evidence that support these changes. The FDA changes will likely have impact on clozapine monitoring protocols in other countries.