Clozapine Flashcards
To what class of drugs does Clozapine belong?
Second Generation Antipsychotics
What is Clozapine’s mechanism of action?
Dopamine D1, Dopamine D2, 5-HT2A, Alpha1-adrenoreceptor, and muscarinic-receptor antagonist
What is Clozapine licensed to treat according to the BNF?
Schizophrenia in patients unresponsive to or intolerant of conventional antipsychotic drugs
Psychoses in Parkinson’s disease
What very serious adverse effects can occur with Clozapine?
Agranulocytosis
Myocarditis and Cardiomyopathy
Intestinal obstruction
What is Aganulocytosis?
severe and dangerous leukopenia (lowered white blood cell count), most commonly of neutrophils causing a neutropenia in the circulating blood
What observation should alert a clinician to the risk of myocarditis or cardiomyopathy in patient being treated with Clozapine?
Persistent tachycardia particularly in the first 2 months of commencing treatment
How should treatment from Clozapine be withdrawn?
Reduce dose over 1-2 weeks to avoid rebound psychosis
What is the regime for monitoring leucocyte and differential blood counts whilst taking Clozapine?
Monitor differential WBC weekly for 18 weeks, then fortnightly for up to one year, then monthly thereafter
How often should blood lipids and weight be measured?
Weight at baseline and regularly for first 3 months
Blood lipids at baseline then 3 months
Both should be rechecked at 3 monthly intervals for first year then yearly thereafter
What are the very common/common side-effects with Clozapine?
Anorexia Constipation Hypersalivation Malaise Speech disorders urinary incontinence Weight gain Dry mouth Blurred vision
What medication can be used to treat hypersalivation?
Hyoscine Hydrobromide
When might it not be appropriate to treat a patient with Hyoscine Hydrobromide?
If patient is at risk of additive antimuscarinic side effects of hyoscine and clozapine.
What is the starting dose for Clozapine - ages 18-59?
12.5mg 1-2 times per day for day 1
25-50 mg for day 2
if tolerated increase over next 14-21 days by 25-50mg per day to max 300mg divided dose
Up to 200mg max in largest dose - taken at bedtime.
Is clozapine normally commenced by primary care?
No normally commenced in hospital
Contra-inidcations to Clozapine?
Alcholic/toxic psychoses Bone Marrow Disorders History of Agranulocytosis History of circulatory collapse History of neutropenia Severe cardiac disorders Severe CNS depression Uncontrolled epilepsy Paralytic ileus
