Overdose : מינון יתר

4.9   Overdose
Intoxications generally occur only after more severe overdoses because of the relatively wide therapeutic range.
Symptoms of overdose
In the event of an overdose, the adverse reactions described in section 4.8, in particular, can occur with increased severity, depending on the dose administered:
- extrapyramidal disorders: acute dyskinetic or dystonic symptoms, glossopharyngeal dystonia. oculogyric crises, laryngeal or pharyngeal spasms.
- somnolence and even coma, occasionally agitation and confusion with delirium.
- cerebral seizures.
- hyperthermia or hypothermia.
- cardiovascular: hypotension, but also hypertension, tachycardia or bradycardia, ECG abnormalities such as arrhythmia (PQ or QT interval prolongation, torsades de pointes), heart and circulatory failure (rapid if massive intoxication),
- anticholinergic effects: blurred vision, raised intraocular pressure, glaucoma attack, reduced intestinal motility, urinary retention.
- respiratory complications: respiratory depression, respiratory arrest, aspiration, cyanosis, pneumonia.
Measures in the event of overdose
Intensive care treatment should be initiated as quickly as possible.
Treatment is symptomatic. Volume replacement, anticonvulsants and vasoconstrictors (norepinephrine, not epinephrine) may be used and, if there are cardiac complications, antiarrhythmics and/or sodium hydrogen carbonate or lactate may be necessary.
The ECG and vital signs should be monitored until the ECG has returned to normal.
Analeptics are contraindicated as there is a tendency to cerebral seizures due to the lowering of the seizure threshold caused by fluphenazine decanoate. Beta-blockers should also be avoided because they increase vasodilatation.
If there are severe extrapyramidal symptoms, antiparkinsonians, e.g., biperiden, should be administered IV; in some cases, it may be necessary to administer the antiparkinsonian medication for several weeks.
Highbody temperature should be treated with antipyretics, and with ice baths if necessary.
Hypothermia should be treated by slow warming.
If an anticholinergic syndrome occurs, physostigmine salicylate is available as an antidote for use under intensive care conditions (with ECG monitoring).
Given the large volume of distribution and high degree of plasma protein binding, forced diuresis and hemodialysis are not very useful in the case of pure fluphenazine intoxications.
Diazepam should only be given to treat seizures if facilities for artificial ventilation are available (because of the risk of respiratory depression).