Due to license restrictions, mandatory blood monitoring must be undertaken in all patients prescribed clozapine. These restrictions apply because a small number of clozapine patients may develop neutropenia.
Patients prescribed clozapine will have full blood count (FBC) measurements taken to the following schedule:
|Baseline for registration|
|Weekly||For a minimum of 18 weeks from start|
|Fortnightly||From the end of weekly monitoring to a minimum of 52 weeks|
|Monthly||For as long as treatment continues post 52 weeks|
|Twice weekly||If an amber result is obtained. Continue until green|
|Daily||If a red result is obtained. Continue until two successive green results|
Note: Patients may only progress from weekly to fortnightly or fortnightly to 4 weekly FBC if authorised by the clozapine monitoring service.
Clozapine clinics and wards must have reliable processes for ensuring clozapine FBCs are taken as scheduled.
FBCs are normally sent to the clozapine monitoring service’s laboratory for analysis. If samples are analysed locally it is the responsibility of the ward or clozapine clinic to inform pharmacy that a local sample has been taken and to act upon the result.
Clozapine discontinuation FBC monitoring will be undertaken as required by the clozapine monitoring service.
Once a FBC is entered, the patient is assigned a coloured "status":
|Blood counts (x 109/L)||Classification||Action|
|WBC ≥ 3.5
neutrophils ≥ 2.0
|GREEN||Continue clozapine treatment|
|WBC ≥ 3.0 and < 3.5
neutrophils ≥ 1.5 and < 2.0
|AMBER||Increase monitoring frequency to TWICE weekly until GREEN|
|WBC < 3.0
neutrophils < 1.5
|RED||STOP clozapine treatment immediately. DAILY bloods until TWO consecutive GREEN results|