CLOZAPINE
(Clozaril, AA-Clozapine, Gen-Clozapine)Standard Prescription
clozapine__mg PO__(frequnecy)
Dosages
Patient must be registered prior to initiation: see note in comments.
Note: Different brands have individual blood monitoring programs and
are considered non-interchangeable.Initial: 6.25-12.5 mg PO HS on day 1,
then increase as tolerated by 6.25-25 mg increments (usually twice weekly) to target dose. May divide doses BID (approx. two-thirds of dose at HS and one-third of dose in AM) to reduce hypotensive effects and dizziness.
Children/ Adolescents:
Suggested dose range 100-400 mg/day
Adults:
Suggested dose range: 225-450 mg/day
Maximum: 900 mg/day, Dosage reduction may be required in patients with renal or hepatic impairment.
If treatment is interrupted for >48 hrs, clozapine should be restarted at initial dosage (see above) and re-titrated to target dose as tolerated.
Mechanism of Action
A second generation, atypical antipsychotic
Forms Supplied
tablet: 25 mg, 100 mg
(Gen-clozapine only: 50 mg, 200 mg tablet are not stocked at BCCH)
Clozaril brand not stocked at BCCH.
Physician/pharmacist must register patient with manufacturer-specific hematological monitoring program and obtain routine CBC on weekly, bi-weekly or every 4 week basis, or more frequently if toxicity develops (see manufacturer guidelines).
Clozaril brand not stocked at BCCH.
Physician/pharmacist must register patient with manufacturer-specific hematological monitoring program and obtain routine CBC on weekly, bi-weekly or every 4 week basis, or more frequently if toxicity develops (see manufacturer guidelines).
Comments
Risk of agranulocytosis (US data): 0.7/1000 patient-years. Risk highest in first 6 months of use, and drops exponentially over time..
Use of clozapine is restricted to patients who have failed trials of two other (structurally unrelated) antipsychotic agents.
Gradual upward dosage titration required due to sedation, postural hypotension, tachycardia.
Use of clozapine is restricted to patients who have failed trials of two other (structurally unrelated) antipsychotic agents.
Gradual upward dosage titration required due to sedation, postural hypotension, tachycardia.
Adverse effects: drowsiness, dizziness, syncope, hypotension, tachycardia, hypersalivation (while asleep), urinary incontinence, increased appetite. Rare: seizures, myocarditis (recommended monitoring for myocarditis includes baseline ECG and echocardiogram, CRP and troponin I at baseline and weekly x 4 weeks).
Lower incidence of extrapyramidal symptoms, tardive dyskinesia and prolactin elevation compared to other antipsychotics.
May cause rug interactions via inhibition of CYP 1A2 and 3A4.
Clozapine is a CYP1A2 substrate . Serum levels are affected by strong CYP1A2 inhibitors/ inducers, including polycyclic aromatic hydrocarbons in cigarette smoke. Dose adjustment required if smoking status changes.
Risk of metabolic abnormalities (including weight gain, hyperglycemia and lipid abnormalities). Must do baseline & periodic assessment of height, weight, waist circumference, blood pressure, fasting glucose & lipid profile. Refer to www.camesaguideline.org for more information.References
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Last Edited
2021-08-01 22:17:52