Drug information of Clozapine
Clozapine is an antipsychotic medication. It works by changing the actions of chemicals in the brain. Clozapine is used to treat severe schizophrenia, or to reduce the risk of suicidal behavior in people with schizophrenia or similar disorders.
Mechanism of effect
Clozapine's antipsychotic actioncombination of antogistic effects at D2 receptors in the mesolimbic pathway and 5-HT2A receptors in the frontal cortex. D2 antagonism relieves positive symptoms while 5-HT2A antagonism alleviates negative symptoms.
Clozapine is a selective monoaminergic antagonist with high affinity for the serotonin Type 2 (5HT2), dopamine Type 2 (D2), 1 and 2 adrenergic, and H1 histaminergic receptors.
Absorption: Rapid and almost complete. Approximately 50% of the administered dose is excreted in the urine and 30% in the feces. Half life: 8 hours (range 4-12 hours)
Usual Adult Dose for Schizophrenia Initial dose: 12.5 mg orally once or twice a day Titration and Maintenance: May increase total daily dose in increments of 25 mg to 50 mg per day to a target dose of 300 mg to 450 mg per day (administered in divided doses) by the end of week 2.
Subsequent dose increases can be in increments of up to 100 mg once or twice weekly. Maximum dose: 900 mg per day
1-Clozapine can cause neutropenia (a low absolute neutrophil count (ANC)), defined as a reduction below pre-treatment normal levels of blood neutrophils. 2-Hypotension, bradycardia, syncope, and cardiac arrest have occurred with Clozapine treatment. 3-Use caution when administering Clozapine to patients with a history of seizures or other predisposing risk factors for seizure (e.g., head trauma or other CNS pathology, use of medications that lower the seizure threshold, or alcohol abuse). 4-Consider the possibility of myocarditis or cardiomyopathy in patients receiving Clozapine who present with chest pain, dyspnea, persistent tachycardia at rest, palpitations, fever, flu-like symptoms, hypotension, other signs or symptoms of heart failure, or electrocardiographic findings (low voltages, ST-T abnormalities, arrhythmias, right axis deviation, and poor R wave progression). 5-Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. 6-QT prolongation, Torsades de Pointes and other life-threatening ventricular arrhythmias, cardiac arrest, and sudden death have occurred with Clozapine treatment. 7-Weight gain has occurred with the use of antipsychotics, including Clozapine.
Points of recommendation
1--In the event of planned discontinuation, reduce the dose gradually over a period of 1 to 2 weeks. 2-May be taken with or without food 3- Patients should be advised to contact their health care professional if they miss taking their drug for more than 2 days. 4-Patients should be informed of the significant risk of developing agranulocytosis and that their participation in the CLOZAPINE REMS Program is designed to reduce this risk; patients will need to immediately report symptoms consistent with severe neutropenia or infection (e.g. fever, weakness, lethargy, or sore throat). 5-This drug may impair judgment, thinking, or motor skills, and carries a risk of seizures; patients should be cautioned about engaging in activities that could cause serious risk to self or others if a sudden loss of consciousness were to occur.