Clozapine Monitoring

Patients on clozapine should have regular haematological monitoring. If neutropenia occurs, the Laboratory Consultant will ensure that the Clinician responsible for the patient is aware of the abnormal result.

Management of Neutropenia

• WBC <3.5 x 10⁹/L or significant drop (>3.0) from baseline or infection: repeat CBC and differential. If repeat WBC <3.5 or neutrophils 1.5-2.0 then monitor twice weekly.
• First 18 weeks of treatment with clozapine:
  • WBC <3.0 x 10⁹/L or neutrophil <1.5 x 10⁹/L: Clozapine should be stopped. Ensure the contact details (including out of hours arrangements) of the Psychiatrist and case manager are in the patient’s notes. Inform the on-call Haematologist.
• After 18 weeks of treatment with clozapine:
  • WBC <2.5 x 10⁹/L or neutrophil <1.0 x 10⁹/L: Clozapine should be stopped. Ensure the contact details (including out of hours arrangements) of the Psychiatrist and case manager are in the patient’s notes. Inform the on-call Haematologist.
• Daily CBCs until neutrophils are clearly rising and >0.5 x 10⁹/L. Temperature to be taken BD. Monitor patient closely for symptoms of infection. Treat temperature >38⁰ with broad-spectrum antibiotics. Many of these patients may struggle to self-monitor at home.
• WBC <2.0 x 10⁹/L or neutrophils £1.0 x 10⁹/L: consider administration of G-CSF. Admit under Haematology if any features of infections or any concerns re self-monitoring. If neutrophils <0.5 x 10⁹/L, place in isolation.

Note: Guidelines for use of G-CSF: G-CSF (5 mcg/kg/day) until neutrophils > 1.0 x 10⁹/L for 2 successive days if neutrophils £1 x 10⁹/L. Pegylated GCSF is an option, and gives a longer duration of action (6 mg SC once only gives an effect of 10 days duration).