Directions for use and doses
IM, in the gluteal region.
Intended exclusively for adults, exclusively for intramuscular administration. Do not administer i.v.
Doses exceeding 3 ml should be avoided to avoid an unpleasant feeling of fullness at the injection site.
Adults: Patients on long-term treatment with oral antipsychotics (mainly haloperidol) may be advised to switch to depot injections. The dose should be adjusted on an individual basis due to significant individual differences in response. Dose selection should be carried out under strict medical supervision of the patient. The choice of the initial dose is carried out taking into account the symptoms of the disease, its severity, the dose of haloperidol or other antipsychotics prescribed during previous treatment.
At the beginning of treatment, it is recommended to prescribe doses 10-15 times higher than the dose of oral haloperidol every 4 weeks, which usually corresponds to 25-75 mg of haloperidol decanoate (0.5-1.5 ml). The maximum initial dose should not exceed 100 mg.
Depending on the effect, the dose can be increased stepwise by 50 mg until the optimal effect is obtained. Typically the maintenance dose corresponds to 20 times the daily dose of oral haloperidol. If symptoms of the underlying disease return during dose titration, treatment with haloperidol decanoate can be supplemented with oral haloperidol. Typically, injections are given every 4 weeks, but due to large individual differences in effectiveness, more frequent use of the drug may be required.
Elderly patients and patients with oligophrenia: a lower initial dose is recommended, for example, 12.5–25 mg every 4 weeks. In the future, depending on the effect, the dose may be increased.
Pharmacological properties of the drug Haloperidol decanoate
Haloperidol decanoate is a long-acting antipsychotic drug. After intramuscular administration, the active substance, the antipsychotic haloperidol, which in its chemical structure is a butyrophenone derivative, is gradually released from the haloperidol decanoate ester by hydrolysis. It has a central antidopaminergic effect. By blocking dopaminergic receptors in the mesocortical and limbic systems, haloperidol is effective in the treatment of hallucinations and delusions. The drug has a pronounced calming effect during psychomotor agitation. Due to the pronounced antidopamine effect associated with the influence on the chemoreceptors of the trigger zone and adenohypophysis, the drug has a pronounced antiemetic effect. After intramuscular administration, the maximum concentration of active haloperidol in the blood serum is reached on days 3–9, after which it decreases. The half-life of Haloperidol decanoate is 3 weeks. With monthly administration, a stable concentration of the drug in the blood plasma is established after 2–4 months. The pharmacokinetics of Haloperidol decanoate after intramuscular administration is dose-dependent. A linear relationship was identified between the administration of the drug at a dose below 450 mg and the resulting concentration of haloperidol in the blood plasma. The empirically established concentration in the blood required for the manifestation of a therapeutic effect ranges from 4 to 20–25 μg/l. Haloperidol penetrates the BBB. The drug is 92% bound to blood plasma proteins, excreted from the body in the form of metabolites, 60% in feces, 40% in urine.
Overdose of the drug Haloperidol decanoate, symptoms and treatment
With parenteral use of the long-acting drug (Haloperidol decanoate), the likelihood of overdose is lower than with oral use of haloperidol. If an overdose of Haloperidol decanoate is suspected, the prolonged nature of the drug's action should be taken into account. The main signs of overdose: severe extrapyramidal disorders (muscle rigidity, possible muscle hypertonicity, generalized or local tremor), arterial hypotension or hypertension (arterial hypertension), severe lethargy. In some cases, coma with respiratory depression may develop against the background of severe arterial hypotension. Ventricular arrhythmias may occur with prolongation of the QT . There is no specific antidote. Symptomatic therapy is carried out: the stomach is washed, activated charcoal is used. In a comatose state, the function of the respiratory system is supported, if necessary, with the use of a ventilator. Monitoring of ECG and critical hemodynamic parameters is necessary. To treat patients with severe arterial hypotension or circulatory failure, it is necessary to administer a sufficient volume of fluid, blood plasma or concentrated albumin intravenously, as well as the administration of vasopressive agents (norepinephrine or dopamine). Epinephrine should not be used because in combination with haloperidol it can cause paradoxical hypotension. For severe extrapyramidal disorders, antiparkinsonian drugs are prescribed parenterally.
Side effects of the drug Haloperidol decanoate
CNS Extrapyramidal symptoms With long-term use, tremor, muscle rigidity, bradykinesia, akathisia, acute muscular dystonia, oculogyric crisis, laryngeal dystonia are possible. To eliminate them, antiparkinsonian drugs with anticholinergic effects should be prescribed, however, it must be taken into account that their constant use reduces the effectiveness of haloperidol. Tardive dyskinesia As with other antipsychotics, it may occur with prolonged use or discontinuation of the drug. It manifests itself as rhythmic movements of the muscles of the face, lips, tongue or lower jaw that are not subject to volitional control. Discontinue when taking haloperidol again, increasing the dose, or switching to another antipsychotic. If signs of tardive dyskinesia appear, it is advisable to continue treatment with another drug. Neuroleptic malignant syndrome A rare reaction that occurs as an idiosyncrasy, characterized by hyperthermia, generalized muscle rigidity, autonomic lability and impaired consciousness. An early sign of neuroleptic malignant syndrome is often hyperthermia. If characteristic symptoms appear, it is necessary to interrupt treatment with the antipsychotic and, under conditions of careful observation, begin maintenance and detoxification therapy. Other side effects from the central nervous system In some cases, depression, lethargy (up to a state similar to lethargy) or agitation, various dyssomnic phenomena, headache, transient mnestic-intellectual disorders, dizziness, motor restlessness, feelings of anxiety, fear or euphoria, epileptic grand mal seizures and resumption of psychotic symptoms. Digestive tract In rare cases - nausea, vomiting, loss of appetite and dyspeptic symptoms. Both an increase and a decrease in body weight are possible. Endocrine system Due to the antidopamine effect, hyperprolactinemia, galactorrhea, gynecomastia, oligo- and amenorrhea may occur. Hypoglycemia and decreased secretion of antidiuretic hormone were observed extremely rarely. Cardiovascular system In some cases, tachycardia and arterial hypotension may occur. Extremely rare: prolongation of the QT on the ECG and/or the appearance of ventricular arrhythmias. These disorders were noted in patients receiving the drug in high doses, or with a predisposition to disorders of the cardiovascular system. Other side effects Rarely, a slight decrease in the number of blood cells was detected, very rarely - agranulocytosis and thrombocytopenia (usually when combining haloperidol with other drugs), extremely rarely - changes in liver function, hepatitis (most often cholestatic). In exceptional cases, hypersensitivity reactions (urticaria, photosensitivity, anaphylaxis) were detected. Cases of constipation, blurred vision, dry mouth, urinary retention, priapism, erectile dysfunction, peripheral edema, increased sweating, salivation, heartburn, changes in body temperature (both increased and decreased) have been reported. In elderly patients, attacks of angle-closure glaucoma may be detected. Reactions at the injection site are also possible.
Special instructions for the use of the drug Haloperidol decanoate
Isolated cases of sudden death of psychiatric patients taking antipsychotic drugs, in particular haloperidol, have been described. QT interval on the ECG was observed in a number of patients during treatment with haloperidol , the drug should be used with caution in patients at risk of prolongation of the QT QT syndrome , hypokalemia, simultaneous use of other drugs that can cause prolongation of the QT T ). If the use of Haloperidol decanoate is necessary, oral haloperidol should be administered first to determine possible hypersensitivity. Due to the fact that haloperidol is metabolized in the liver, caution is required when using the drug in severe hepatic pathology. With long-term use, periodic monitoring of blood counts and liver function is necessary. Isolated cases of the development of convulsive syndrome during the use of haloperidol have been described. Therefore, patients with epilepsy, as well as patients with increased convulsive readiness (chronic intoxication of alcohol or other origins, a history of traumatic brain injury, etc.), should be prescribed haloperidol decanoate with caution. For patients whose psychopathological disorders include symptoms of depressive syndrome, haloperidol should be prescribed in combination with antidepressants. During the initial period of treatment with the drug, you should not drive vehicles or work in conditions with an increased risk of injury. Subsequently, the degree of restrictions is determined individually. Treatment with the drug is incompatible with drinking alcohol. It has been experimentally established that haloperidol does not significantly increase the number of congenital pathologies. In some cases, congenital developmental anomalies have been described during the use of haloperidol during pregnancy (usually when the drug is used in combination with other drugs). Thus, haloperidol can be prescribed during pregnancy only if the expected benefits of treatment clearly exceed the possible teratogenic effect. Haloperidol passes into breast milk. In some cases, extrapyramidal disorders have been observed in newborns whose mothers took haloperidol. Therefore, when prescribing haloperidol, it is recommended to stop breastfeeding. When stored at low temperatures, a fraction of the active component may be released from the solution. This phenomenon can be eliminated by warming the ampoules in your hands or keeping them at room temperature for a certain time. For administration, only homogeneous solution can be used!
Drug interactions Haloperidol decanoate
Thyroxine increases the toxicity of haloperidol, therefore, in patients with hyperthyroidism, haloperidol can only be used under the guise of adequate thyreostatic therapy. If there is a need for simultaneous antiparkinsonian therapy for the patient, a break should be taken after the last dose of Haloperidol decanoate, given its prolonged effect. The drug can enhance the effect of central nervous system depressants - alcohol, sedatives and hypnotics, as well as narcotic analgesics. Concomitant use of haloperidol with these drugs may cause respiratory depression. Enhances the effect of methyldopa on the central nervous system. Reduces the antiparkinsonian effect of levodopa. Haloperidol decanoate inhibits the metabolism of tricyclic antidepressants, so their levels in the blood plasma may increase with increased anticholinergic effects, as well as toxicity, including in relation to the cardiovascular system. Pharmacokinetic studies revealed a moderate or moderate increase in the concentration of haloperidol in the blood serum when used simultaneously with quinidine, buspirone, and fluoxetine. If their combined use is necessary, a reduction in the dose of haloperidol may be necessary. With long-term use of drugs that have the properties of liver enzyme inducers (carbamazepine, rifampicin, phenobarbital, etc.), the concentration of haloperidol in the blood decreases. Therefore, if their combined use is necessary, an increase in the dose of haloperidol may be required. In case of subsequent discontinuation of therapy with these drugs, the advisability of reducing the dose of Haloperidol decanoate should be kept in mind. Rarely, with the combined use of Haloperidol decanoate and lithium salts, encephalopathy, extrapyramidal symptoms, tardive dyskinesia, neuroleptic malignant syndrome, brain stem symptoms, and coma were noted. In most cases, such disorders are reversible. The reason for their manifestation in this situation is not clear. If these disorders occur, you should immediately stop using Haloperidol decanoate. Haloperidol may reduce the effectiveness of oral anticoagulant therapy. Haloperidol inhibits the action of epinephrine and other sympathomimetics, and also reduces the effectiveness of antihypertensive adrenergic blocking agents.
