LEPONEX Clozapine 25mg Tablet 1's
Indications/Uses
Treatment-resistant schizophrenia: Clozapine (Leponex) is indicated in patients with treatment-resistant schizophrenia, i.e. patients with schizophrenia who are non-responsive to or intolerant of classic antipsychotics.
Non-responsiveness is defined as a lack of satisfactory clinical improvement despite the use of adequate doses of at least two marketed antipsychotics prescribed for adequate durations.
Intolerance is defined as the impossibility of achieving adequate clinical benefit with classic antipsychotics because of severe and untreatable neurological adverse reactions (extrapyramidal side effects or tardive dyskinesia).
Risk of recurrent suicidal behavior: Clozapine (Leponex) is indicated for reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder who are judged to be at chronic risk for re-experiencing suicidal behavior, based on history and recent clinical state. Suicidal behavior refers to actions by a patient that put him/herself at high risk for death.
Psychosis during the course of Parkinson's disease: Clozapine (Leponex) is indicated in psychotic disorders occurring during the course of Parkinson's disease, in cases where standard treatment has failed.
The failure of standard treatment is defined as the lack of control of the psychotic symptoms and/or the onset of functionally unacceptable motoric deterioration occurring after the following measures have been taken: Withdrawal of anticholinergic medication including tricyclic antidepressants; Attempt to reduce the dose of antiparkinsonian medication with dopaminergic effect.
Dosage/Direction for Use
Dosage information: The dosage must be adjusted individually. For each patient the lowest effective dose should be used. Cautious titration and a divided dosage schedule are necessary to minimize the risks of hypotension, seizure, and sedation.
Initiation of treatment must be restricted to those patients with a WBC count ≥3500/mm3 (3.5 x 109/L) and an ANC ≥2000/mm3 (2.0 x 109/L), and within standardized normal limits.
Dose adjustment is indicated in patients who are also receiving medicinal products that have pharmacokinetic interactions with clozapine, such as benzodiazepines or selective serotonin re-uptake inhibitors (see Interactions).
Switching from a previous antipsychotic therapy to Clozapine (Leponex): It is generally recommended that clozapine should not be used in combination with other antipsychotics. When clozapine (Leponex) therapy is to be initiated in a patient undergoing oral antipsychotic therapy, it is recommended that the dosage of other antipsychotics be reduced or discontinued by gradually tapering it downwards. Based on the clinical circumstances, the prescribing physician should judge whether or not to discontinue the other antipsychotic therapy before initiating treatment with clozapine.
Treatment resistant schizophrenia: Starting therapy: Clozapine (Leponex) should be started with 12.5 mg (half a 25 mg tablet) once or twice on the first day, followed by one or two 25 mg tablets on the second day. If well tolerated, the daily dose may then be increased slowly in increments of 25 mg to 50 mg in order to achieve a dose level of up to 300 mg/day within 2 to 3 weeks. Thereafter, if required, the daily dose may be further increased in increments of 50 mg to 100 mg at half-weekly or, preferably, weekly intervals.
Therapeutic dose range: In most patients, antipsychotic efficacy can be expected with 300 to 450 mg/day given in divided doses. Some patients may be treated with lower doses, and some patients may require doses up to 600 mg/day. The total daily dose may be divided unevenly, with the larger portion being taken at bedtime.
Maximum dose: To obtain full therapeutic benefit, a few patients may require larger doses, in which case judicious increments (not exceeding 100 mg) are permissible up to 900 mg/day. However the possibility of increased adverse reactions (in particular seizures) occurring at doses over 450 mg/day must be borne in mind.
Maintenance dose: After achieving maximum therapeutic benefit, many patients can be maintained effectively on lower doses. Careful downward titration is therefore recommended. Treatment should be maintained for at least 6 months. If the daily dose does not exceed 200 mg, once daily administration in the evening may be appropriate.
Ending therapy: In the event of planned termination of clozapine therapy, a gradual reduction in dose over a 1- to 2-week period is recommended. If abrupt discontinuation is necessary (e.g. because of leucopenia), the patient should be carefully observed for the recurrence of psychotic symptoms and symptoms related to cholinergic rebound (see Precautions).
Restarting therapy: In patients in whom the interval since the last dose of clozapine (Leponex) exceeds 2 days, treatment should be re-initiated with 12.5 mg (half a 25-mg tablet) given once or twice on the first day. If this dose is well tolerated, it may be feasible to titrate the dose to the therapeutic level more quickly than is recommended for initial treatment. However, in any patient who has previously experienced respiratory or cardiac arrest with initial dosing (see Precautions), but was then able to be successfully titrated to a therapeutic dose, re-titration should be done with extreme caution.
Reducing the risk of suicidal behavior in schizophrenia and schizoaffective disorder: The dosage and administration recommendations described in the preceding subsection regarding the use of clozapine (Leponex) in patients with treatment-resistant schizophrenia should also be followed when treating patients with schizophrenia or schizoaffective disorder at risk for recurrent suicidal behaviour.
A course of treatment with clozapine (Leponex) of at least two years is recommended in order to maintain the reduction of risk for suicidal behaviour. It is recommended that the patient's risk of suicidal behaviour be reassessed after two years of treatment and that thereafter the decision to continue treatment with clozapine be re-visited at regular intervals, based on thorough assessments of patient's risk for suicidal behaviour during treatment.
Psychotic disorders occurring during the course of Parkinson's disease, in cases where standard treatment has failed: Starting therapy: The starting dose must not exceed 12.5 mg/day (half a 25 mg tablet), taken in the evening. Subsequent dose increases must be by 12.5 mg increments, with a maximum of two increments a week up to a maximum of 50 mg, a dose that cannot be reached until the end of the second week. The total daily amount should preferably be given as a single dose in the evening.
Therapeutic dose range: The mean effective dose is usually between 25 and 37.5 mg/day. In the event that treatment for at least one week with a dose of 50 mg fails to provide a satisfactory therapeutic response, dosage may be cautiously increased by increments of 12.5 mg/week.
Maximum dose: The dose of 50 mg/day should only be exceeded in exceptional cases, and the maximum dose of 100 mg/day must never be exceeded.
Dose increases should be limited or deferred if orthostatic hypotension, excessive sedation or confusion occurs. Blood pressure should be monitored during the first weeks of treatment.
Maintenance dose: When there has been complete remission of psychotic symptoms for at least 2 weeks, an increase in anti-parkinsonian medication is possible if indicated on the basis of motor status. If this approach results in the recurrence of psychotic symptoms, Clozapine (Leponex) dosage may be increased by increments of 12.5 mg/week up to a maximum of 100 mg/day, taken in one or two divided doses (see previously mentioned).
Ending therapy: When ending therapy, a gradual reduction in dose by steps of 12.5 mg over a period of at least one week (preferably two) is recommended.
Treatment must be discontinued immediately in the event of neutropenia or agranulocytosis as indicated in Precautions. In this situation, careful psychiatric monitoring of the patient is essential since symptoms may recur quickly.
Special Populations: Cardiovascular disorders: In patients suffering from cardiovascular disorders (note: severe cardiovascular disorders are contraindications) the initial dose should be 12.5 mg given once on the first day, and dosage increase should be slow and in small increments.
Renal impairment: In patients with mild to moderate renal impairment the initial dose should be 12.5 mg given once on the first day, and dosage increase should be slow and in small increments.
Hepatic impairment: Patients with hepatic impairment should receive clozapine (Leponex) with caution along with regular monitoring of liver function tests (see Precautions).
Pediatrics: No pediatric studies have been performed. The safety and efficacy of clozapine (Leponex) in children and adolescents have not been established.
Patients 60 years of age and older: It is recommended that treatment in patients 60 years and older is initiated at a particularly low dose (12.5 mg given once on the first day) with subsequent dose increments restricted to 25 mg/day.
Method of administration: Clozapine (Leponex) is administered orally.
Overdosage
In cases of acute intentional or accidental clozapine overdosage, for which information on the outcome is available, to date the mortality is about 12%. Most of the fatalities were associated with cardiac failure or pneumonia caused by aspiration and occurred at doses above 2000 mg. There have been reports of patients recovering from an overdose in excess of 10,000 mg. However, in a few adult individuals, primarily those not previously exposed to clozapine, the ingestion of doses as low as 400 mg led to life-threatening comatose conditions and, in one case, to death. In young children, the intake of 50 mg to 200 mg resulted in strong sedation or coma without being lethal.
Signs and symptoms: Drowsiness, lethargy, areflexia, coma, confusion, hallucinations, agitation, delirium, extrapyramidal symptoms, hyper-reflexia, convulsions; hypersalivation, mydriasis, blurred vision, thermolability; hypotension, collapse, tachycardia, cardiac arrhythmias; aspiration pneumonia, dyspnea, respiratory depression or failure.
Treatment: There are no specific antidotes for clozapine.
Gastric lavage and/or the administration of activated charcoal within the first 6 hours after clozapine ingestion. (Peritoneal dialysis and hemodialysis are unlikely to be effective.) Symptomatic treatment under continuous cardiac monitoring, surveillance of respiration, monitoring of electrolytes and acid-base balance. The use of epinephrine should be avoided in the treatment of hypotension because of the possibility of a 'reverse epinephrine' effect.
Close medical supervision is necessary for at least 5 days because of the possibility of delayed reactions.
Administration
May be taken with or without food.
Contraindications
Known hypersensitivity to clozapine or to any of the excipients.
Patients unable to undergo regular blood tests.
History of toxic or idiosyncratic granulocytopenia/agranulocytosis (with the exception of granulocytopenia/agranulocytosis from previous chemotherapy).
Impaired bone marrow function.
Uncontrolled epilepsy.
Alcoholic and other toxic psychoses, drug intoxication, comatose conditions.
Circulatory collapse and/or CNS depression of any cause.
Severe renal or cardiac disorders (e.g. myocarditis).
Active liver disease associated with nausea, anorexia or jaundice; progressive liver disease, hepatic failure.
Paralytic ileus.
Warnings
Clozapine (Leponex) can cause agranulocytosis. Its use should be limited to patients: with schizophrenia who are non-responsive to or intolerant of classical antipsychotic agents, or with schizophrenia or schizoaffective disorder who are at risk of recurrent suicidal behavior (see Indications); who have initially normal leukocyte findings (white blood cell count (WBC) ≥3500/mm3 (≥3.5 x 109/L) and absolute neutrophil counts (ANC) ≥2000/mm3 (≥2.0 x 109/L)); and in whom regular white blood cell counts and absolute neutrophil counts can be performed as follows: weekly during the first 18 weeks of therapy, and at least every 4 weeks thereafter throughout treatment. Monitoring must continue throughout treatment and for 4 weeks after complete discontinuation (see Precautions).
Prescribing physicians should comply fully with the required safety measures. At each consultation, a patient receiving the medication should be reminded to contact the treating physician immediately if any kind of infection begins to develop. Particular attention should be paid to flu-like complaints such as fever or sore throat and to other evidence of infection, which may be indicative of neutropenia (see Precautions).
Clozapine (Leponex) must be dispensed under strict medical supervision in accordance with official recommendations (see Precautions).
Special Precautions
Special precautionary measure: Agranulocytosis: Because of the association of clozapine with agranulocytosis, the following precautionary measures are mandatory: Drugs known to have a substantial potential to depress bone marrow function should not be used concurrently with clozapine. In addition, the concomitant use of long-acting depot antipsychotics should be avoided because of the impossibility of removing these medications, which may be potentially myelosuppressive, from the body rapidly in situations where this may be required, e.g. granulocytopenia.
Patients with a history of primary bone marrow disorders may be treated only if the benefit outweighs the risk. They should be carefully reviewed by a haematologist prior to starting therapy.
Patients who have low white blood cell (WBC) counts because of benign ethnic neutropenia should be given special consideration and may be started on clozapine after agreement of a haematologist.
Clozapine (Leponex) must be dispensed under strict medical supervision in accordance with official recommendations.
White Blood Cell (WBC) counts and Absolute Neutrophil Count (ANC) monitoring: White blood cell count (WBC) and differential blood counts must be performed within 10 days prior to starting treatment to ensure that only patients with normal leukocyte (WBC ≥3500/mm3 (≥3.5 x 109/L)) and absolute neutrophil counts (ANC ≥2000/mm3 (≥2.0 x 109/L)) will receive clozapine. After the start of clozapine (Leponex) treatment, regular WBC count and ANC must be performed and monitored weekly for 18 weeks, and thereafter at least every four weeks throughout treatment, and for 4 weeks after complete discontinuation.
Prescribing physicians should comply fully with the required safety measures. At each consultation, the patient should be reminded to contact the treating physician immediately if any kind of infection begins to develop. Particular attention should be paid to flu-like complaints such as, fever or sore throat and to other evidence of infection, which may be indicative of neutropenia. A differential blood count must be performed immediately if any symptoms or signs of an infection occur.
Low WBC count and/or ANC: If during the first 18 weeks of clozapine (Leponex) therapy, the WBC count falls to between 3500/mm3 and 3000/mm3 and/or the ANC falls to between 2000/mm3 and 1500/mm3, haematological evaluations must be performed at least twice weekly.
After 18 weeks of therapy, haematological evaluations should be performed at least twice weekly if the WBC count falls to between 3000/mm3 and 2500/mm3 and/or the ANC falls to between 1500/mm3 and 1000/mm3.
In addition, if, during therapy, the WBC count is found to have dropped by a substantial amount from baseline, a repeat WBC count and a differential blood count should be performed. A substantial drop is defined as a single drop of 3000 mm3 or more in the WBC count or a cumulative drop of 3000 mm3 or more within three weeks.
Immediate discontinuation of clozapine (Leponex) is mandatory if the WBC count is less than 3000/mm3 or the ANC is less than 1500/mm3 during the first 18 weeks of therapy, or if the WBC count is less than 2500/mm3 or the ANC is less than 1000/mm3 after the first 18 weeks of therapy. WBC counts and differential blood counts should then be performed daily and patients should be carefully monitored for flu-like symptoms or other symptoms suggestive of infection. Following discontinuation of treatment, haematological evaluation is required until haematological recovery has occurred.
If clozapine has been withdrawn and WBC count falls further to below 2000/mm3 and/or the ANC falls below 1000/mm3, the management of this condition must be guided by an experienced haematologist. If possible, the patient should be referred to a specialised haematological unit, where protective isolation and the administration of GM-CSF (granulocyte-macrophage colony stimulating factor) or G-CSF (granulocyte colony stimulating factor) may be indicated. It is recommended that the colony stimulating factor therapy be discontinued when the neutrophil count has returned to a level above 1000/mm3.
Patients in whom clozapine has been discontinued as a result of white blood cell deficiencies (see previously mentioned) must not be re-exposed to clozapine.
It is recommended that the haematological values be confirmed by performing two blood counts on two consecutive days; however, clozapine should be discontinued after the first blood count. (See Tables 1 and 2.)
In the event of interruption of therapy for non-hematological reasons: Patients who have been on clozapine (Leponex) for more than 18 weeks and have had their treatment interrupted for more than 3 days but less than 4 weeks should have their WBC count and ANC monitored weekly for an additional 6 weeks. If no hematological abnormality occurs, monitoring at intervals not exceeding 4 weeks may be resumed. If treatment has been interrupted for 4 weeks or longer, weekly monitoring is required for the next 18 weeks of treatment (see Dosage & Administration).
Other Precautions: Eosinophilia: In the event of eosinophilia, discontinuation of clozapine is recommended if the eosinophil count rises above 3000/mm3. Therapy should be re-started only after the eosinophil count has fallen below 1000/mm3.
Thrombocytopenia: In the event of thrombocytopenia, discontinuation of clozapine is recommended if the platelet count falls below 50 000/mm3.
Cardiovascular disorders: In patients suffering from cardiovascular disorders (note: severe cardiovascular disorders are contraindications) the initial dose should be 12.5 mg given once on the first day, and dosage increase should be slow and in small increments (see Dosage & Administration).
Orthostatic hypotension, with or without syncope, can occur during clozapine treatment. Rarely (about one case per 3000-treated patients), collapse can be profound and may be accompanied by cardiac and/or respiratory arrest. Such events are more likely to occur during initial titration in association with rapid dose escalation; on very rare occasions they occurred even after the first dose. Therefore, patients commencing treatment require close medical supervision.
Myocarditis and Cardiomyopathy; Tachycardia that persists at rest, accompanied by arrhythmias, shortness of breath or signs and symptoms of heart failure, may rarely occur during the first month of treatment and very rarely thereafter. The occurrence of these signs and symptoms necessitates an urgent diagnostic evaluation for myocarditis, especially during the titration period. If the diagnosis of myocarditis is confirmed, clozapine should be discontinued. There have been postmarketing reports of myocarditis including fatal cases. Later in treatment, the same signs and symptoms may very rarely occur and may be linked to cardiomyopathy. Further investigation should be performed and if the diagnosis is confirmed, the treatment should be stopped unless the benefit clearly outweighs the risk to the patient.
In patients who are diagnosed with cardiomyopathy while on clozapine treatment, there is potential to develop mitral valve incompetence. Mitral valve incompetence has been reported in cases of cardiomyopathy related to clozapine treatment. These cases of mitral valve incompetence reported either mild or moderate mitral regurgitation on two-dimensional echocardiography (2DEcho) (see Adverse Reactions).
Monitoring of standing and supine blood pressure is necessary during the first weeks of treatment in patients with Parkinson's disease.
Myocardial infarction: There have been postmarketing reports of myocardial infarction including fatal cases. Causality assessment was difficult in the majority of these cases because of serious pre-existing cardiac disease and plausible alternative causes.
QT interval prolongation: As with other antipsychotics, caution is advised in patients with known cardiovascular disease or family history of QT prolongation.
As with other antipsychotics, caution should be exercised when clozapine is prescribed with medicines known to increase the QTc interval.
Cerebrovascular adverse events: An increased risk of cerebrovascular adverse events has been seen in the dementia population with some atypical antipsychotics. The mechanism for this increased risk is not known. An increased risk cannot be excluded for other antipsychotics or other patient populations. Clozapine should be used with caution in patients with risk factors for stroke.
Risk of thromboembolism: Since clozapine may cause sedation and weight gain, thereby increasing the risk of thromboembolism, immobilization of patients should be avoided.
Metabolic changes: Atypical antipsychotic drugs, including clozapine, have been associated with metabolic changes that may increase cardiovascular/cerebrovascular risk. These metabolic changes may include hyperglycemia, dyslipidemia, and body weight gain. While atypical antipsychotic drugs may produce some metabolic changes, each drug in the class has its own specific risk profile.
Hyperglycemia: On rare occasions, severe hyperglycemia, sometimes leading to ketoacidosis/hyperosmolar coma, has been reported during clozapine treatment in patients with no prior history of hyperglycemia. While a causal relationship to clozapine use has not been definitely established, glucose levels returned to normal in most patients after discontinuation of clozapine, and re-challenge produced a recurrence of hyperglycemia in a few cases. The effect of clozapine on glucose metabolism in patients with diabetes mellitus has not been studied. Impaired glucose tolerance, severe hyperglycemia, ketoacidosis and hyperosmolar coma have been reported in patients with no prior history of hyperglycemia. Patients with an established diagnosis of diabetes mellitus who are started on atypical antipsychotics should be monitored regularly for worsening of glucose control. Patients with risk factors for diabetes mellitus (e.g., obesity, family history of diabetes) who are starting treatment with atypical antipsychotics should undergo fasting blood glucose testing at the beginning of treatment and periodically during treatment. Exacerbation should be considered in patients receiving clozapine who develop symptoms of hyperglycemia, such as polydipsia, polyuria, polyphagia or weakness. Patients who develop symptoms of hyperglycemia during treatment with atypical antipsychotics should undergo fasting blood glucose testing. In some cases, hyperglycemia has resolved when the atypical antipsychotic was discontinued; however, some patients required continuation of antidiabetic treatment despite discontinuation of the suspect drug. In patients with significant treatment-emergent hyperglycemia, discontinuation of clozapine (Leponex) should be considered.
There is a risk of altering the metabolic balance resulting in slight impairment of glucose homeostasis and a possibility of unmasking a pre-diabetic condition or aggravating pre-existing diabetes.
Dyslipidemia: Undesirable alterations in lipids have been observed in patients treated with atypical antipsychotics, including clozapine. Clinical monitoring, including baseline and periodic follow-up lipid evaluations in patients using clozapine, is recommended.
Weight gain: Weight gain has been observed with atypical antipsychotic use, including clozapine. Clinical monitoring of weight is recommended.
Seizures: Clozapine may lower seizure threshold. In patients with a history of seizures the initial dose should be 12.5 mg given once on the first day, and dosage increase should be slow and in small increments (see Dosage & Administration).
Anticholinergic effects: Clozapine exerts anticholinergic activity, which may produce undesirable effects throughout the body. Careful supervision is indicated in the presence of prostatic enlargement and narrow-angle glaucoma. Probably on account of its anticholinergic properties, clozapine has been associated with varying degrees of impairment of intestinal peristalsis, ranging from constipation to intestinal obstruction, fecal impaction, paralytic ileus, megacolon and intestinal infarction/ischaemia (see Adverse Reactions). On rare occasions these cases have proved fatal.
Fever: During clozapine therapy, patients may experience transient temperature elevations above 38°C, with the peak incidence within the first 3 weeks of treatment. This fever is generally benign. Occasionally, it may be associated with an increase or decrease in the WBC count. Patients with fever should be carefully evaluated to rule out the possibility of an underlying infection or the development of agranulocytosis. In the presence of high fever, the possibility of neuroleptic malignant syndrome (NMS) must be considered. If the diagnosis of NMS is confirmed, clozapine should be discontinued immediately and appropriate medical measures should be administered.
Falls: Clozapine may cause seizures, somnolence, postural hypotension, motor and sensory instability, which may lead to falls and, consequently, fractures or other injuries. For patients with diseases, conditions, or medications that could exacerbate these effects, complete fall risk assessments when initiating antipsychotic treatment and recurrently for patients on long-term antipsychotic therapy.
Rebound, withdrawal Effects: If abrupt discontinuation of clozapine treatment is necessary (e.g. because of leucopenia), the patient should be carefully observed for the recurrence of psychotic symptoms and symptoms related to cholinergic rebound such as profuse sweating, headache, nausea, vomiting and diarrhea.
Driving and using machines: Owing to the ability of clozapine to cause sedation and lower the seizure threshold, activities such as driving or operating machinery should be avoided, especially during the initial weeks of treatment.
Special Populations: Hepatic impairment: Patients with stable pre-existing liver disorders may receive clozapine, but must undergo regular liver function tests. Such tests should be performed immediately in patients who develop symptoms of possible liver dysfunction such as nausea, vomiting and/or anorexia during treatment. If the elevation of the values is clinically relevant or if symptoms of jaundice occur, treatment must be discontinued. It may be resumed (see Re-starting therapy under Dosage & Administration) only when the results of liver function tests are normal. In such cases, liver function should be closely monitored after re-introduction of clozapine.
Renal impairment: In patients suffering from mild to moderate renal impairment, an initial dose of 12.5 mg/day (half a 25 mg tablet) is recommended (see Dosage & Administration).
Use in Elderly: Patients aged 60 years and older: It is recommended that treatment be initiated at a particularly low dose (12.5 mg given once on the first day) and subsequent dose increments be restricted to 25 mg/day.
Clinical studies with clozapine did not include sufficient numbers of subjects aged 60 years and over to determine whether or not they respond differently from younger subjects.
Orthostatic hypotension can occur with clozapine (Leponex) treatment and there have been rare reports of tachycardia, which may be sustained. Patients aged 60 years and older, particularly those with compromised cardiovascular function, may be more susceptible to these effects.
Patients aged 60 years and older may also be particularly susceptible to the anticholinergic effects of clozapine, such as urinary retention and constipation.
Patients aged 60 years and older with Dementia-related Psychosis: In patients aged 60 years and older with dementia-related psychosis, the efficacy and safety of clozapine has not been studied. Observational studies suggest that patients aged 60 years and older with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. In the published literature, risk factors that may predispose this patient population to increased risk of death when treated with antipsychotics include sedation, the presence of cardiac conditions (e.g. cardiac arrhythmias) or pulmonary conditions (e.g. pneumonia, with or without aspiration). Clozapine (Leponex) should be used with caution in patients aged 60 years and older with dementia.
Use In Pregnancy & Lactation
Women of child-bearing potential and contraceptive measures: Some female patients treated with antipsychotics other than clozapine may become amenorrheic. A return to normal menstruation may occur as a result of switching from other antipsychotics to clozapine. Adequate contraceptive measures must therefore be ensured in women of childbearing potential.
Use in Pregnancy: Reproduction studies in animals have revealed no evidence of impaired fertility or harm to the fetus due to clozapine. However, the safe use of clozapine in pregnant women has not been established. Therefore, clozapine (Leponex) should be used in pregnancy only if the expected benefit clearly outweighs any potential risk.
Non-teratogenic effects: Neonates exposed to antipsychotic drugs, during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress and feeding disorder in these neonates. These complications have varied in severity; while in some cases symptoms have been self-limited, in other cases neonates have required intensive care unit support and prolonged hospitalization.
Antipsychotic drugs, including clozapine, should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Use in Lactation: Animal studies suggest that clozapine is excreted in breast milk and has an effect in the suckling offspring. Therefore, mothers receiving clozapine (Leponex) should not breast-feed.
Adverse Reactions
Summary of the safety profile: The adverse effects of clozapine are most often predictable based on its pharmacological properties with the exception of agranulocytosis (see Precautions).
The most serious adverse reactions experienced with clozapine are agranulocytosis, seizure, cardiovascular effects and fever (see Precautions). The most common side effects are drowsiness/sedation, dizziness, tachycardia, constipation, and hypersalivation.
Data from the clinical trials experience showed that a varying proportion of clozapine-treated patients (from 7.1 to 15.6%) were discontinued due to an adverse event, including only those that could be reasonably attributed to clozapine. The more common events considered to be causes of discontinuation were leukopenia; somnolence; dizziness (excluding vertigo); and psychotic disorder.
Adverse drug reactions (ADRs) are listed by MedDRA system organ class (see Table 3). Within each system organ class, the adverse reactions are ranked by frequency, using the following convention: Very common (≥1/10), common (≥1/100, <1/10), uncommon (≥1/1,000, <1/100), rare (≥1/10,000, <1/1,000), very rare (<1/10,000), including isolated reports. Within each frequency grouping, adverse drug reactions are presented in order of decreasing seriousness.
Very rare events of ventricular tachycardia, cardiac arrest and QT prolongation which may be associated with Torsades De Pointes have been observed although there is no conclusive causal relationship to the use of this medicine.
Adverse drug reactions from spontaneous reports and literature (frequency not known): The following adverse drug reactions (ADRs) were derived from post-marketing experience with clozapine (Leponex) via spontaneous case reports and literature cases and have been categorized according to MedDRA system organ class (see Table 4). Because these reactions have been reported voluntarily from a population of uncertain size and are subject to confounding factors, these post-marketing ADRs have been categorized with a frequency of "not known" since it is not possible to reliably estimate their frequency. Adverse drug reactions are listed according to system organ classes in MedDRA. Within each system organ class, ADRs are presented in order of decreasing seriousness.
Drug Interactions
Pharmacodynamic-related interactions: Anticipated pharmacodynamic interactions resulting in concomitant use not being recommended: Medicinal products known to have a substantial potential to depress bone marrow function should not be used concurrently with clozapine (Leponex) (see Precautions).
As with other antipsychotics, caution should be exercised when clozapine is prescribed with medicines known to increase the QTc interval or causing electrolyte imbalance.
Observed pharmacodynamic interactions to be considered: Particular caution is recommended when clozapine therapy is initiated in patients who are receiving (or have recently received) a benzodiazepine or any other psychotropic agent, as these patients may have an increased risk of circulatory collapse, which, on rare occasions, can be profound and may lead to cardiac and/or respiratory arrest.
Concomitant use of lithium or other CNS-active agents may increase the risk of development of neuroleptic malignant syndrome (NMS).
Rare but serious reports of seizures, including onset of seizures in non-epileptic patients, and isolated cases of delirium where clozapine was co-administered with valproic acid have been reported. These effects are possibly due to a pharmacodynamic interaction, the mechanism of which has not been determined.
Anticipated pharmacodynamic interactions to be considered: Clozapine may enhance the central effects of alcohol, MAO inhibitors and CNS depressants such as narcotics, antihistamines, and benzodiazepines.
Because of the possibility of additive effects, caution is essential when substances possessing anticholinergic, hypotensive, or respiratory depressant effects are given concomitantly.
Owing to its anti-alpha-adrenergic properties, clozapine may reduce the blood pressure-increasing effect of norepinephrine or other predominantly alpha-adrenergic agents and reverse the pressor effect of epinephrine.
Pharmacokinetic-related interactions: Clozapine is a substrate for many CYP 450 isoenzymes, in particular 1A2 and 3A4. The risk of metabolic interactions caused by an effect on an individual isoform is therefore minimized. Nevertheless, caution is called for in patients receiving concomitant treatment with other substances that are either inhibitors or inducers of these enzymes.
No clinically relevant interactions have been observed thus far with tricyclic antidepressants, phenothiazines or type 1C anti-arrhythmics, which are known to bind to cytochrome P450 2D6.
Observed pharmacokinetic interactions to be considered: Concomitant administration of substances known to induce cytochrome P450 enzymes may decrease the plasma levels of clozapine: Substances known to induce the activity of 3A4 and with reported interactions with clozapine include, for instance, carbamazepine, phenytoin and rifampicin.
Concomitant administration of substances known to inhibit the activity of cytochrome P450 isozymes may increase the plasma levels of clozapine: Substances known to inhibit the activity of the major isozymes involved in the metabolism of clozapine and with reported interactions include, for instance, cimetidine, erythromycin (3A4), fluvoxamine (1A2), perazine (1A2) ciprofloxacin (1A2) and oral contraceptives (1A2, 3A4, 2C19).
The plasma concentration of clozapine is increased by caffeine (1A2) intake and decreased by nearly 50% following a 5-day caffeine-free period.
Elevated clozapine plasma concentrations also have been reported in patients receiving the substances in combination with selective serotonin re-uptake inhibitors (SSRIs) such as paroxetine (1A2), sertraline, fluoxetine or citalopram.
Anticipated pharmacokinetic interactions to be considered: Concomitant administration of substances known to induce cytochrome P450 enzymes may decrease the plasma levels of clozapine: Known inducers of 1A2 include, for instance, omeprazole and tobacco smoke. In cases of sudden cessation of tobacco smoking, the plasma clozapine concentration may be increased, thus leading to an increase in adverse effects.
Concomitant administration of substances known to inhibit the activity of cytochrome P450 isozymes may increase the plasma levels of clozapine: Potent inhibitors of CYP3A, such as azole antimycotics and protease inhibitors, could potentially also increase clozapine plasma concentrations; no interactions have been reported to date, however.
Caution For Usage
Incompatibilities: Not applicable.
Storage
Store at temperatures not exceeding 30°C.
Action
Pharmacology: Pharmacodynamics: Clinically clozapine produces rapid and marked sedation, and exerts antipsychotic effects in patients with schizophrenia resistant to other antipsychotic agents. In such cases, clozapine has proven effective in relieving both positive and negative schizophrenic symptoms in short- and long-term trials.
Clozapine is unique in that it produces virtually no major extrapyramidal reactions such as acute dystonia and tardive dyskinesia. Furthermore, parkinsonian-like side effects and akathisia are rare. In contrast to classical antipsychotics, clozapine produces little or no prolactin elevation, thus avoiding adverse effects such as gynecomastia, amenorrhea, galactorrhea, and impotence.
Potentially serious adverse reactions caused by clozapine therapy are granulocytopenia and agranulocytosis occurring at an estimated incidence of 3% and 0.7% respectively (see Precautions).
Mechanism of action: Clozapine (Leponex) has been shown to be an antipsychotic agent that is different from classic antipsychotics.
In pharmacological experiments, the compound does not induce catalepsy or inhibit apomorphine- or amphetamine-induced stereotyped behavior. It has only weak dopamine receptor-blocking activity at D1, D2, D3 and D5 receptors, but shows high potency for the D4 receptor, in addition to potent anti-alpha-adrenergic, anticholinergic, antihistaminic, and arousal reaction-inhibiting effects. It has also been shown to possess antiserotoninergic properties.
Clinical Studies: Clinical studies in treatment-resistant schizophrenia (Clozapine study 16 & 30): The first study was Study 16, a randomized, double-blind, multicenter, parallel group comparative trial of clozapine versus chlorpromazine (CPZ) in hospitalized patients (aged 18 to 65 years and of either sex) with treatment resistant schizophrenia (DSM-II criteria). 151 such patients were randomly assigned to either clozapine (150-900 mg) or chlorpromazine (300-1800 mg) for 28 days with an optional extension up to 28 days (75 in clozapine group and 76 in chlorpromazine group). Efficacy was assessed by measuring mean change from baseline in the Brief Psychiatric Rating Scale (BPRS), Clinical Global Impression (CGI) scores and the Nurses Observation Scale for Inpatient Evaluation (NOSIE-30). Throughout the study, and at endpoint, clozapine patients had a more rapid onset of action and showed significant improvement in BPRS items compared to chlorpromazine patients. At week 1, clozapine was statistically superior to CPZ in two items assessed: Motor retardation [0.67 vs. 0.12; p<0.05] and blunted affect [0.93 vs. 0.34; p<0.01]. At week 2, two more items also showed statistically significant improvements in clozapine group, emotional withdrawal [1.48 vs. 0.98; p<0.01] and unusual thought content [2.06 vs. 1.45; p<0.05]. At week 3, clozapine was statistically superior in 7 out of the 18 BPRS items assessed. At endpoint, clozapine showed statistically significant improvements in every item assessed. Results were similar for BPRS factors and CGI scores also. By week 2, statistically significant differences favoring clozapine were observed in the BPRS Total Score and maintained throughout the duration of study. Tests of comparative efficacy at endpoint showed clozapine to be significantly better for all five factors assessed: anxiety/depression (0.85 vs. 0.54; p<0.05), anergia (1.15 vs. 0.72; p<0.001), thought disturbance (1.80 vs. 1.28; p <0.01), activation (1.34 vs. 0.89; p<0.01), and hostile/suspiciousness (1.26 vs. 0.74; p<0.01)). At endpoint, clozapine showed statistically significant improvements in mean change in total BPRS score [22.53 vs. 14.64, p<0.001] and CGI [1.95 vs. 1.33, p<0.01]. Clozapine patients generally did better in the all NOSIE factors, except for social competence. Mean change from baseline showed statistically significant differences favoring clozapine in the improvement of irritability at weeks 3 (6.28 vs. 0.67, p<0.01) and week 4 (6.84 vs. 1.36, p<0.05). For most of the factors, particularly, total patient assets, there was clear evidence of an early onset of therapeutic benefit with clozapine, thus corroborating BPRS data, although no statistical difference was observed. At endpoint, clozapine was superior to CPZ for the following NOSIE factors: social interest (4.14 vs. 3.24), personal neatness (3.19 vs. 2.26), irritability (3.04 vs. 0.60) and manifest psychosis (6.32 vs. 4.24) as well as total assets (20.54 vs. 16.66).
Second study was Study 30, a randomized, double-blind, multicenter, parallel group, 6-week, comparative study of clozapine versus chlorpromazine plus benztropine. The study population included 319 treatment-resistant schizophrenic patients, between the ages of 18-60 years, who met DSM-III criteria for schizophrenia, refractory to treatment. Eligible patients were randomly assigned to either clozapine (up to 900 mg/day) or chlorpromazine plus benztropine (up to 1800 mg/day of chlorpromazine, plus 6 mg/day of benztropine). Efficacy was assessed using the BPRS score, CGI scale, and NOSIE-30. At the end of 6 weeks, clozapine was significantly superior to chlorpromazine in all "Positive", "Negative" and general symptoms of BPRS (p<0.001) except 'Grandiosity' and 'BPRS total score'. Clozapine showed a significantly superior change in CGI scale compared to chlorpromazine starting at week 1 (p<0.001). Clozapine was superior to chlorpromazine on all six NOSIE-30 factors and total assets starting at either week 1 or 2 (p < 0.05 to 0.001). Clozapine was statistically significant in the following NOSIE factors, social competence, social interest and personal neatness, and total assets (p<0.001), as well as irritability and motor retardation (p<0.01 <0.05, respectively).
Clinical study in risk of recurrent suicidal behavior (InterSePT Trial): The effectiveness of clozapine in reducing the risk of recurrent suicidal behavior was assessed in the International Suicide Prevention Trial (InterSePT), a prospective, randomized, open label, international, parallel-group comparison of clozapine vs. olanzapine in patients with schizophrenia or schizoaffective disorder (DSM-IV) judged to be at risk for re-experiencing suicidal behavior, lasting for 24 months. A total of 956 patients were randomized to either clozapine (starting with 25 mg/day, titrated upwards to 200-900 mg/day) or olanzapine (5-20 mg/day). The primary efficacy measure was time to a significant suicide attempt, including a completed suicide; hospitalization due to imminent suicide risk (including increased level of surveillance for suicidality for patients already hospitalized); or worsening of suicidality severity as demonstrated by "much worsening" or "very much worsening" from baseline in the CGI-SS-BP scale. Clozapine showed a statistically significant overall treatment effect compared to olanzapine for the primary efficacy measure (p=0.0309). Treatment effect for Type 1 events (a significant suicide attempt or hospitalization due to imminent suicide risk (including increased level of surveillance) was statistically significant in favor of clozapine (p=0.0316), with a hazard ratio [risk ratio] of 0.76 (95% C.I.: 0.58, 0.98). Similarly, the treatment effect for Type 2 events (worsening of suicidality severity as demonstrated by 7-point CGI-SS-BP change scale score of 6 or 7, or by implicit worsening of suicidality severity as demonstrated by occurrence of a Type 1 event) was statistically significant in favor of clozapine (p=0.0388), with a hazard ratio of 0.78 (95% C.I.: 0.61, 0.99). Probability (Standard Error, SE) of experiencing a Type 1 and Type 2 events was higher for olanzapine patients compared to clozapine patients at all visits. At week 104, the clozapine treatment group demonstrated a significantly lower probability of both Type 1 (24% vs. 32%; 95% C.I. 2%, 14%) and Type 2 event (28% vs. 37%; 95% C.I.: 2%, 15%).
Clinical study in psychosis in Parkinson's disease: A randomized, double-blind parallel group, multicenter trial was conducted to compare the efficacy of clozapine vs. placebo for the treatment of psychosis in Parkinson's disease (drug-induced psychosis unresponsive to usual management) and to compare the effect of clozapine vs. placebo on the motor function of patients with Parkinson's disease. Study participants included 60 male or female patients (32 clozapine, 28 placebo), who met the diagnosis criteria of idiopathic Parkinson's disease and with the following criteria of antiparkinsonian induced psychosis: psychotic symptoms for ≥2 weeks and requiring treatment (≥4 at item P1 or P3 of the PANSS; MMS > 20; no improvement of psychotic symptoms or unacceptable deterioration of motor function within a week despite usual therapeutic management; CGI-S >4. Patients received either clozapine or placebo for 4 weeks, starting with 10 days titration phase, up to the maximum dose of 50 mg (Period 2). All patients who completed period 2, received clozapine during 12 weeks with flexible dosage up to 150 mg/day (Period 3). Attempt of clozapine withdrawal (over 1 week) was made, with assessment visit 3 weeks later (Period 4). The mean change in CGI-S score (primary efficacy variable) was significantly greater in the clozapine group compared to the placebo group (-1.8 vs. -0.6; p=0.001) at the end of period 2. Significant improvement in CGI-S score was achieved at week 1 and maintained at all time points of period 2 for the clozapine group. At the end of Period 2, the mean change in the PANSS positive subscore (secondary efficacy variable) was significantly greater in the clozapine group than in the placebo group. Significant improvement in the PANSS positive subscores was obtained at week 1 and maintained at all subsequent time points. Reduction in scores of individual items were significant for all items. Clozapine treated patients continued to improve on both parameters during period 3. Improvement was slightly increased at end of period 3 for both the efficacy parameters, CGI-S (clozapine -2.5 vs. -1.8 for placebo) and PANSS (clozapine -7.7 vs. -4.8 for placebo).
Pharmacokinetics: Absorption: The absorption of orally administered clozapine is 90% to 95%; neither the rate nor the extent of absorption is influenced by food.
Clozapine is subject to moderate first-pass metabolism, resulting in an absolute bioavailability of 50% to 60%.
Distribution: In steady-state conditions, when given twice daily, peak blood levels occur on an average at 2.1 hours (range: 0.4 to 4.2 hours), and the volume of distribution is 1.6 L/kg. Clozapine is approximately 95% bound to plasma proteins.
Biotransformation/metabolism: Clozapine is almost completely metabolized before excretion by CYP1A2 and 3A4, and to some extent by CYP2C19 and 2D6. Of the main metabolites only the desmethyl metabolite was found to be active. Its pharmacological actions resemble those of clozapine, but are considerably weaker and of short duration.
Elimination: Its elimination is biphasic, with a mean terminal half-life of 12 hours (range: 6 to 26 hours). After single doses of 75 mg the mean terminal half-life was 7.9 hours; it increased to 14.2 hours when steady-state conditions were reached by administering daily doses of 75 mg for at least 7 days.
Only trace amounts of unchanged drug are detected in the urine and feces, approximately 50% of the administered dose being excreted as metabolites in the urine and 30% in the feces.
Linearity/non-linearity: Dosage increases from 37.5 mg to 75 mg and 150 mg given twice daily were found to result during steady state in linearly dose-proportional increases in the area under the plasma concentration/time curve (AUC), and in the peak and minimum plasma concentrations.
Toxicology: Non-Clinical Safety Data: Preclinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity and carcinogenic potential (for reproductive toxicity, see Use in Pregnancy & Lactation).
Mutagenicity: Clozapine and/or its metabolites were devoid of genotoxic potential when investigated for induction of gene mutations, chromosome aberrations and primary DNA-damage in a spectrum of in vitro mutagenicity tests. Likewise, no genotoxic activity was observed in vivo (bone marrow micronucleus test in mice).
Carcinogenicity: In Sprague-Dawley (CD) rats treated in the diet for 2 years, maximum tolerated doses of 35 mg/kg per day revealed no carcinogenic potential of clozapine. Likewise, no evidence of tumorigenic effects was obtained in two 1.5-year feeding studies in Charles River (CD) mice. In the first study, oral dose levels of up to 64 mg/kg per day were administered to males, and of up to 75 mg/kg per day to females respectively. In the second study, the highest dose for both sexes was 61 mg/kg per day.
Reproductive toxicity: No embryotoxic or teratogenic potential of clozapine was observed in rats or rabbits at daily oral doses of up to 40 mg/kg. In male rats receiving the same dosages for 70 days prior to mating, fertility was unaffected.
In female rats, fertility as well as pre- and postnatal development of the offspring was not adversely affected by oral clozapine treatment prior to mating (up to 40 mg/kg per day). When rats were treated at the same dosages during the later part of pregnancy and during lactation, survival rates of the young from lactating dams were lowered and the young were hyperactive. However, there was no lasting effect on pup development after weaning.
MedsGo Class
Antipsychotics
Features
- Clozapine