| Please also refer to Drug Interactions section.
Cardiac monitoring There have been very rare reports of QT prolongation, ventricular arrhythmias, and Torsade de Pointes in patients without risk factors for QT prolongation administered therapeutic doses of pimozide, and in the setting of overdose. Ventricular tachycardia and ventricular fibrillation (in some cases with fatal outcomes) have also been reported, in addition to very rare reports of sudden death and cardiac arrest.As with other neuroleptics, cases of sudden unexpected death have been reported with pimozide at recommended doses and in the setting of overdose. An ECG should be performed prior to initiation of treatment with pimozide, as well as periodically during treatment. If repolarization changes (prolongation of QT interval, T-wave changes or U-wave development) appear or arrhythmias develop, the need for treatment with pimozide in these patients should be reviewed. They should be closely monitored and their dose of pimozide should be reduced or the drug discontinued. If QT or QTc exceeds 500 msec, pimozide should be discontinued.As with other neuroleptics, caution is advised in patients with cardiovascular diseases, patients with a family history of QT prolongation.Hypotension may very rarely occur.Electrolyte disturbances should also be considered a risk factor (see Section 4.3 Contraindications and Section 4.5 Interaction with other medicinal products and other forms of interaction) and periodic electrolyte monitoring is recommended.Drugs which may cause electrolyte disturbances are not recommended in patients receiving long-term pimozide (please also refer to the Drug Interactions section.)
Venous Thromboembolism (VTE) Cases of venous thromboembolism (VTE) have been reported with antipsychotic drugs. Since patients treated with antipsychotics often present with acquired risk factors for VTE, all possible risk factors for VTE should be identified before and during treatment with Orap and preventive measures undertaken.
Liver disease Caution is advised in patients with liver disease because pimozide is metabolized in the liver.
Kinetics of response/withdrawal In schizophrenia, the response to antipsychotic drug treatment may be delayed. If drugs are withdrawn, recurrence of symptoms may not become apparent for several weeks or months.Acute withdrawal symptoms, including nausea, vomiting, sweating and insomnia, have been described after abrupt cessation of antipsychotic drugs. Recurrence of psychotic symptoms may also occur, and the emergence of involuntary movement disorders (such as akathisia, dystonia and dyskinesia) has been reported. Therefore, gradual withdrawal is advisable.
Extrapyramidal symptoms In common with all neuroleptics, extrapyramidal symptoms may occur (see Section 4.8). Antiparkinson drugs of the anticholinergic type may be prescribed as required, but should not be prescribed routinely as a preventive measure (see tardive dyskinesia below).
Tardive dyskinesia As with all antipsychotic agents, tardive dyskinesia may appear in some patients on long-term therapy or after drug discontinuation. The syndrome is mainly characterized by rhythmical involuntary movements of the tongue, face, mouth or jaw. The manifestations may be permanent in some patients.The syndrome may be masked when treatment is reinstituted, when the dosage is increased or when a switch is made to a different antipsychotic drug. Treatment should be discontinued as soon as possible.There is no known treatment for tardive dyskinesia. The antipsychotic drug may mask it, as may anticholinergic agents. Although the latter do not predispose to tardive dyskinesia, they should not be used routinely to mask the Parkinsonian effects of antipsychotic drugs as they may mask the early signs of tardive dyskinesia.
Neuroleptic malignant syndrome In common with other antipsychotic drugs, pimozide has been associated with neuroleptic malignant syndrome: an idiosyncratic response characterized by hyperthermia, generalised muscle rigidity, autonomic instability, altered consciousness. Hyperthermia is often an early sign of this syndrome.Antipsychotic treatment should be withdrawn immediately and appropriate supportive therapy and careful monitoring instituted.
Seizures As with other antipsychotic drugs, pimozide should be used cautiously in patients with a history of seizures or other conditions that potentially lower the seizure threshold (e.g. alcohol withdrawal or brain damage). In addition, grand mal convulsions have been reported in association with pimozide.
Body Temperature Regulation Disruption of the body's ability to reduce core body temperature has been attributed to antipsychotic agents. Appropriate care is advised when prescribing pimozide to patients who will be experiencing conditions which may contribute to an elevation in core body temperature, e.g., exercising strenuously, exposure to extreme heat, receiving concomitant medication with anticholinergic activity or being subject to dehydration.
Endocrine Effects Hormonal effects of antipsychotic neuroleptic drugs include hyperprolactinaemia, which may cause galactorrhoea, gynaecomastia, oligomenorrhoea or amenorrhoea, and erectile dysfunction.Pimozide should only be used with great caution in patients with thyrotoxicosis.
Increased Mortality in Elderly people with Dementia Data from two large observational studies showed that elderly people with dementia who are treated with antipsychotics are at a small increased risk of death compared with those who are not treated. There are insufficient data to give a firm estimate of the precise magnitude of the risk and the cause of the increased risk is not known.Orap is not licensed for the treatment of dementia-related behavioural disturbances.
Other Caution is also advised in patients with renal failure, Parkinson's disease and phaeochromocytoma. Concomitant use of pimozide with other neuroleptics should be avoided.
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