Anti-psychotics i.e. Clozapine Flashcards
What are the indications of clozapine?
Schizophrenia, treatment-resistant schizophrenia, psychosis, psychosis occurring in Parkinson’s disease, acute mania, Tourette’s syndrome, nausea and vomiting, short term management of severe anxiety, challenging behaviour e.g. antisocial sexual behaviour, intractable hiccup, pain relief.
What are the contraindications of clozapine?
Alcoholic and toxic psychosis, bone marrow disorders, coma, drug intoxication, history of agranulocytosis, history of circulatory collapse, history of neutropenia, paralytic ileus, severe cardiac disorders e.g. myocarditis, severe CNS depression, uncontrolled epilepsy.
State the mechanism of action for anti-psychotics.
Anti-psychotics work by reducing the neurotransmission effects of dopamine, noradrenalin and serotonin (mainly dopamine). Dopamine is a neurotransmitter that is released by neurons to transmit signals to other nerve cells. The dopamine hypothesis of schizophrenia states that too much dopamine is responsible for symptoms, and taking anti-psychotics that reduce dopaminergic neurotransmission has been shown to lead to a reduction in symptoms.
What are the very common/common unwanted side effects of clozapine?
Akathisia, anorexia, benign hyperthermia, blurred vision, constipation, convulsions/seizures, decreased white blood cell count/leukopenia/neutropenia, dizziness, dry mouth, dysarthria, ECG changes, elevated liver enzymes, eosinophilia, extrapyramidal symptoms, fatigue, fever, headaches, hypersalivation, hypertension, insulin resistance, leukocytosis, malaise, metabolic syndrome, muscle stiffness, nausea, postural hypotension, QT-elongation, rash, rigidity, sedation, sexual dysfunction, shakiness, sleep disturbances, speech disorders, sweating, syncope, tachycardia, tiredness, tremors, unusual skin pigmentation, urinary incontinence, urinary retention, vomiting, weight gain.
What are the monitoring requirements of clozapine?
Leukocytes and differential blood counts must be normal prior to starting treatment, counts should be monitored every week for 18 weeks, then 2 weeks for up to 1 year, then monthly after 1 year of treatment due to potential for neutropenia and agranulocytosis (dangerously low white blood cell count). Patients should be closely medically supervised when beginning treatment due to risk of collapse due to hypotension and convulsions. Blood lipids and weight should be measured at baseline, 3 months, then yearly due to potential for weight gain. Fasting blood glucose should be measured at baseline, 1 month, 4-6 months then yearly. Patient, prescriber and pharmacist must be registered with the Patient Monitoring Service.
What is the treatment cessation for clozapine?
Reduce dose over 1-2 weeks to avoid risk of rebound psychosis. If stopped abruptly monitor patient closely. There is a high risk of relapse if medication is stopped after 1-2 years. Patients should be monitored for 2 years after withdrawal for signs/symptoms of relapse.
What is the patient and carer advice for clozapine?
Avoid direct sunlight as photosensitisation can occur. Drowsiness may affect driving/performing skilled tasks. Effects of alcohol are enhanced. Advise how to administer oral suspension if necessary.
