Oprex
Oprex Uses, Dosage, Side Effects, Food Interaction and all others data.
Oprex blocks postsynaptic dopamine D1 and D2 receptors in the mesolimbic system and decreases the release of hypothalamic and hypophyseal hormones. It produces calmness and reduces aggressiveness with disappearance of hallucinations and delusions.
Use of the first-generation antipsychotics (including haloperidol) is considered highly effective for the management of the "positive" symptoms of schizophrenia including hallucinations, hearing voices, aggression/hostility, disorganized speech, and psychomotor agitation. However, this class is limited by the development of movement disorders such as drug-induced parkinsonism, akathisia, dystonia, and tardive dyskinesia, and other side effects including sedation, weight gain, and prolactin changes. Compared to the lower-potency first-generation antipsychotics such as Chlorpromazine, Zuclopenthixol, Fluphenazine, and Methotrimeprazine, haloperidol typically demonstrates the least amount of side effects within class, but demonstrates a stronger disposition for causing extrapyramidal symptoms (EPS). Low‐potency medications have a lower affinity for dopamine receptors so that a higher dose is required to effectively treat symptoms of schizophrenia. In addition, they block many receptors other than the primary target (dopamine receptors), such as cholinergic or histaminergic receptors, resulting in a higher incidence of side effects such as sedation, weight gain, and hypotension.
The balance between the wanted drug effects on psychotic symptoms and unwanted side effects are largely at play within dopaminergic brain pathways affected by haloperidol. Cortical dopamine-D2-pathways play an important role in regulating these effects and include the nigrostriatal pathway, which is responsible for causing extrapyramidal symptoms (EPS), the mesolimbic and mesocortical pathways, which are responsible for the improvement in positive schizophrenic symptoms, and the tuberoinfundibular dopamine pathway, which is responsible for hyperprolactinemia.
A syndrome consisting of potentially irreversible, involuntary, dyskinetic movements may develop in patients. Although the prevalence of the syndrome appears to be highest among the elderly, especially elderly women, it is impossible to rely upon prevalence estimates to predict, at the inception of antipsychotic treatment, which patients are likely to develop the syndrome.
Trade Name | Oprex |
Availability | Prescription only |
Generic | Haloperidol |
Haloperidol Other Names | Haloperidol, Haloperidolum |
Related Drugs | hydroxyzine, lorazepam, ondansetron, diazepam, Zofran, meclizine, promethazine, risperidone, Ativan, Depakote |
Type | Tablet, Syrup |
Formula | C21H23ClFNO2 |
Weight | Average: 375.864 Monoisotopic: 375.140134897 |
Protein binding | Studies have found that free fraction of haloperidol in human plasma is 7.5-11.6%. This was found to be comparable among healthy adults, young adults, elderly patients with schizophrenia, and even in patients with liver cirrhosis. |
Groups | Approved |
Therapeutic Class | Butyrophenone drugs, Drugs used in tremor, tics & related disorder |
Manufacturer | Psycormedies |
Available Country | India |
Last Updated: | September 19, 2023 at 7:00 am |
Uses
Adults:
- Schizophrenia: treatment of symptoms and prevention of relapse (oral and IM)
- Other psychoses, especially paranoid (oral and IM)
- Mania and hypomania(oral and IM)
- Mental or behavioural problems such as aggression, hyperactivity and self- mutilations in the mentally retarded and in patients with organic brain damage
- As an adjunct to short-term management of moderate to severe psychomotor agitation, excitement, violent or dangerously impulsive behavior (oral and IM)
- Intractable hiccup (oral)
- Restlessness and agitation in the elderly (oral)
- Gilles de la Tourette syndrome and severe tics (oral)
- Nausea and vomiting (IM)
Children (Oral administration only):
- Childhood behavioral disorders especially when associated with hyperactivity and aggression
- Gilles de la Tourette syndrome
- Childhood schizophrenia
Oprex is also used to associated treatment for these conditions: Chemotherapy-Induced Nausea and Vomiting (CINV), Delirium, Gilles de la Tourette's Syndrome, Huntington's Disease (HD), Obsessive Compulsive Disorder (OCD), Psychosis, Schizophrenia, Aggressive reaction, Severe Hyperactivity, Severe disruptive behaviour disorder
How Oprex works
While haloperidol has demonstrated pharmacologic activity at a number of receptors in the brain, it exerts its antipsychotic effect through its strong antagonism of the dopamine receptor (mainly D2), particularly within the mesolimbic and mesocortical systems of the brain. Schizophrenia is theorized to be caused by a hyperdopaminergic state within the limbic system of the brain. Dopamine-antagonizing medications such as haloperidol, therefore, are thought to improve psychotic symptoms by halting this over-production of dopamine. The optimal clinical efficacy of antipsychotics is associated with the blockade of approximately 60 % - 80 % of D2 receptors in the brain.
While the exact mechanism is not entirely understood, haloperidol is known to inhibit the effects of dopamine and increase its turnover. Traditional antipsychotics, such as haloperidol, bind more tightly than dopamine itself to the dopamine D2 receptor, with dissociation constants that are lower than that for dopamine. It is believed that haloperidol competitively blocks post-synaptic dopamine (D2) receptors in the brain, eliminating dopamine neurotransmission and leading to the relief of delusions and hallucinations that are commonly associated with psychosis. It acts primarily on the D2-receptors and has some effect on 5-HT2 and α1-receptors, with negligible effects on dopamine D1-receptors. The drug also exerts some blockade of α-adrenergic receptors of the autonomic system.
Antagonistic activity regulated through dopamine D2 receptors in the chemoreceptive trigger zone (CTZ) of the brain renders its antiemetic activity. Of the three D2-like receptors, only the D2 receptor is blocked by antipsychotic drugs in direct relation to their clinical antipsychotic abilities.
Clinical brain-imaging findings show that haloperidol remains tightly bound to D2 dopamine receptors in humans undergoing 2 positron emission tomography (PET) scans with a 24h pause in between scans. A common adverse effect of this drug is the development of extrapyramidal symptoms (EPS), due to this tight binding of haloperidol to the dopamine D2 receptor.
Due to the risk of unpleasant and sometimes lifelong extrapyramidal symptoms, newer antipsychotic medications than haloperidol have been discovered and formulated. Rapid dissociation of drugs from dopamine D2 receptors is a plausible explanation for the improved EPS profile of atypical antipsychotics such as Risperidone. This is also consistent with the theory of a lower affinity for D2 receptors for these drugs. As mentioned above, haloperidol binds tightly to the dopamine receptor, potentiating the risk of extrapyramidal symptoms, and therefore should only been used when necessary.
Dosage
Oprex dosage
Oral Administration-
Adults: Schizophrenia, Psychoses, Mania and Hypomania, Mental or behavioral problems, Psychomotor agitation, Excitement, Violent or dangerously impulsive behavior, Organic brain damage.Initial dosage:
- Moderate symptomatology 1.5-3.0 mg bd or tds.
- Severe symptomatology/resistant patients 3.0-5.0 mg bd or tds. The same starting doses may be employed in adolescents, who in certain cases, may require up to 30 mg or exceptionally up to 60 mg/day
- In resistant schizophrenics daily dosages up to 100 mg (or rarely up to 120 mg) may be necessary to achieve an optimal response.
Maintenance dosage:
- Once satisfactory control of symptoms has been achieved dosage, dosage should be gradually reduced to the lowest maintenance dose, often as low as 5 mg/day. Too rapid a dosage reduction should be avoided.
- Restlessness or agitation in elderly: Initial dose 1.5- 3.0 mg bd or tds titrated to attain an effective maintenance dose (1.5-5.0 mg daily)
- Gilles de la tourette syndrome/Severe tics/Intractable hiccup: Starting dose1.5 mg tds adjusted according to response. A daily maintenance dose of 10 mg may be required in Gilles de la tourette syndrome.
Children:
- Childhood behavioural disorder/schizophrenia: Total daily maintenance dose of 0.025-0.05 mg/kg/day. Half the total dose should be given in the morning and the other half in the evening, up to a maximum of 10 mg daily. Not recommended for parenteral use in children.
Parenteral Administration-
Administered intramuscularly in doses of 2 to 5 mg, is utilized for prompt control of the acutely agitated schizophrenic patient with moderately severe to very severe symptoms. Depending on the response of the patient, subsequent doses may be given, administered as often as every hour, although 4 to 8 hour intervals may be satisfactory. The maximum dose is 20 mg/day.
Dosage for all indications should be individually determined and is best initiated and titrated under close clinical supervision. To determine the initial dose consideration should be given to the patients age, severity of symptoms and previous response to other neuroleptics. The normal starting dose should be halved, followed by a gradual titration to achieve an optimal response.
Side Effects
Extrapyramidal symptoms, acute dystonia, parkinsonian rigidity, tremor, oculogyric crises and laryngeal dystonia, confusional states or epileptic fits, depression, sedation, agitation, drowsiness, insomnia, headache, vertigo and apparent exacerbation of psychotic symptoms, nausea, loss of appetite, constipation and dyspepsia, dry mouth as well as excessive salivation, blurred vision, urinary retention have been reported.
Toxicity
Acute oral toxicity (LD50): 71 mg/kg in rats .
Precaution
Caution is advised in patients with liver disease, renal failure, epilepsy and conditions predisposing to epilepsy (e.g. alcohol withdrawal and brain damage) or convulsions. Oprex should only be used with great caution in patients with disturbed thyroid function.
Interaction
Oprex has been reported to interfere with the anticoagulant properties of phenindione in an isolated case and the possibility should be kept in mind of a similar effect occurring when haloperidol is used with other anticoagulants. Oprex may antagonize the action of epinephrine and other sympathomimetic agents and reverse the blood pressure-lowering effects of adrenergic-blocking agents, such as guanethidine. Enhanced CNS effects may occur when haloperidol is used in combination with methyldopa. Oprex inhibits the metabolization of tricyclic antidepressants, thereby increasing plasma levels of these drugs. This may result in increased tricyclic antidepressant toxicity (anticholinergic effects, cardiovascular toxicity, lowering of seizure threshold). Oprex may impair the antiparkinson effects of levodopa. If an antiparkinson agent is used concomitantly with haloperidol, both drugs should not be discontinued simultaneously, since extrapyramidal symptoms may occur due to the slower excretion rate of haloperidol.
Food Interaction
- Avoid alcohol. Alcohol may potential hypotension and CNS adverse effects.
[Moderate] GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents.
Use in combination may result in additive central nervous system depression and
MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol.
Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
Oprex Drug Interaction
Major: escitalopram, escitalopram, quetiapine, quetiapine, sertraline, sertralineModerate: aripiprazole, aripiprazole, lorazepam, lorazepam, divalproex sodium, divalproex sodiumUnknown: acetaminophen, acetaminophen, acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, cholecalciferol, cholecalciferol
Oprex Disease Interaction
Major: dementia, hyperthyroidism, parkinsonism, CNS depression/coma, related psychosis, previous neuroleptic malignant syndrome (NMS), seizure disorders, acute alcohol intoxication, cardiovascular disease, CNS depression, NMS, tardive dyskinesiaModerate: seizure, alcohol, cardiovascular disease, QT prolongation, renal/liver disease, hyperprolactinemia/breast cancer, neutropenia, dehydration, hyperprolactinemia
Volume of Distribution
The apparent volume of distribution was found to range from 9.5-21.7 L/kg. This high volume of distribution is in accordance with its lipophilicity, which also suggests free movement through various tissues including the blood-brain barrier.
Elimination Route
Oprex is a highly lipophilic compound and is extensively metabolized in humans, which may cause a large interindividual variability in its pharmacokinetics.
Studies have found a wide variance in pharmacokinetic values for orally administered haloperidol with 1.7-6.1 hours reported for time to peak plasma concentration (tmax), 14.5-36.7 hours reported for half-life (t1⁄2), and 43.73 μg/L•h [range 14.89-120.96 μg/L•h] reported for AUC. Oprex is well-absorbed from the gastrointestinal tract when ingested orally, however, the first-pass hepatic metabolism decreases its oral bioavailability to 40 - 75%.
After intramuscular administration, the time to peak plasma concentration (tmax) is 20 minutes in healthy individuals or 33.8 minutes in patients with schizophrenia, with a mean half-life of 20.7 hours. Bioavailability following intramuscular administration is higher than that for oral administration.
Administration of haloperidol decanoate (the depot form of haloperidol for long-term treatment) in sesame oil results in slow release of the drug for long-term effects. The plasma concentrations of haloperidol gradually rise, reaching its peak concentration at about 6 days after the injection, with an apparent half-life of about 21 days. Steady-state plasma concentrations are achieved after the third or fourth dose.
Half Life
Following oral administration, the half-life was found to be 14.5-36.7 hours. Following intramuscular injection, mean half-life was found to be 20.7 hours.
Clearance
Following intravenous administration, the plasma or serum clearance (CL) was found to be 0.39-0.708 L/h/kg (6.5 to 11.8 ml/min/kg). Following oral administration, clearance was found to be 141.65 L/h (range 41.34 to 335.80 L/h).
Oprex clearance after extravascular administration ranges from 0.9-1.5 l/h/kg, however this rate is reduced in poor metabolizers of CYP2D6 enzyme. Reduced CYP2D6 enzyme activity may result in increased concentrations of haloperidol. The inter-subject variability (coefficient of variation, %) in haloperidol clearance was estimated to be 44% in a population pharmacokinetic analysis in patients with schizophrenia .
Genetic polymorphism of CYP2D6 has been demonstrated to be an important source of inter-patient variability in the pharmacokinetics of haloperidol and may affect therapeutic response and incidence of adverse effects.
Elimination Route
In radiolabeling studies, approximately 30% of the radioactivity is excreted in the urine following a single oral administration of 14C-labelled haloperidol, while 18% is excreted in the urine as haloperidol glucuronide, demonstrating that haloperidol glucuronide is a major metabolite in the urine as well as in plasma in humans.
Pregnancy & Breastfeeding use
There is no proven harmful effect in the first trimester, however there have been some reports of limb malfonnations, so the drug is best avoided if possible. The principal hazard in late pregnancy is extrapyramidal adverse effects in the neonate. The drug is excreted only in trace amounts and sedation or extrapyramidal rigidity in the neonate can occur but is rarely a problem.
Contraindication
Comatose states; CNS depression; Parkinson's disease; known hypersensitivity to haloperidol; lesions of the basal ganglia.
Acute Overdose
In general, the symptoms of overdosage would be an exaggeration of known pharmacologic effects and adverse reactions, the most prominent of which would be: severe extrapyramidal reactions, hypotension or sedation.The patient would appear comatose with respiratory depression and hypotension which could be severe enough to produce a shock-like state.
Storage Condition
Store at 15-30° C.
Innovators Monograph
You find simplified version here Oprex
Oprex contains Haloperidol see full prescribing information from innovator Oprex Monograph, Oprex MSDS, Oprex FDA label
FAQ
What is Oprex used for?
Oprex also is used in the treatment of schizophrenia, tics in Tourette syndrome, mania in bipolar disorder, delirium, agitation, acute psychosis, and hallucinations in alcohol withdrawal. Oprex is also used to control motor and speech tics in people with. Oprex may also be used for purposes not listed in this medication guide.
How safe is Oprex?
Many people using this Oprex do not have serious side effects. In rare cases, Oprex may increase your level of a certain chemical made by the body. For females, this increase in prolactin may result in unwanted breast milk, missed/stopped periods, or difficulty becoming pregnant.
How does Oprex work?
Oprex works by inhibiting the effects of dopamine and increasing its turnover.
What are the common side effects of Oprex?
The common side effects of Oprex are include;
- dry mouth.
- increased saliva.
- blurred vision.
- loss of appetite.
- constipation.
- diarrhea.
- heartburn.
- nausea.
Is Oprex safe during pregnancy?
Oprex is rated FDA Pregnancy Category C. In animal studies, Oprex rarely induced fetal malformations. In humans, the amount of placental passage shown by the drug is 65.5% ± 40.3%.
Is Oprex safe during breastfeeding?
Oprex possible to use cautiously during breastfeeding. Monitor the infant for drowsiness and developmental milestones, especially if other antipsychotics are used concurrently.
Can I drink alcohol with Oprex?
Alcohol can increase the nervous system side effects of bransd such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with Oprex.
Can I drive after taking Oprex?
Oprex may affect your judgment and impair your ability to drive or operate machinery. It may also increase your risk of falls.
How many time can I take Oprex daily?
It is usually taken two or three times a day. Take Oprex at around the same times every day.
When should be taken of Oprex?
You can take Oprex before or after your meals. Swallow the dose with a drink of water.
How long does Oprex take to work?
Oprex is absorbed quickly but it may take a few days to a few weeks for psychotic symptoms or symptoms of Tourette syndrome to abate. The maximum effects are usually seen within four to six weeks.
How long does Oprex stay in my system?
The half-life of the drug is approximately 3 weeks.
Can I take Oprex every day?
Oprex should be taken every day as ordered by your healthcare provider.
How do I stop taking Oprex?
Do not stop receiving Oprex suddenly without asking your doctor. You may need to slowly decrease your dose before stopping it completely.
When should I stop taking Oprex?
Symptoms may include fever, rigid or stiff muscles, changed mood, irregular pulse or blood pressure, fast or irregular heartbeat, and unexplainable sweating. If you experience these symptoms, stop taking Oprex right away and get medical help.
Who should not take Oprex?
You should not use Oprex if you are allergic to it, or if you have: Parkinson's disease; or. certain conditions that affect your central nervous system. Oprex is not approved for use in older adults with dementia-related psychosis.
What happens if I miss a dose?
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What happens if I overdose?
Seek emergency medical attention. An overdose of Oprex can be fatal.
Can Oprex affect my heart?
Oprex can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.
Can you just stop Oprex?
You should not stop taking Oprex abruptly as it may lead to the development of withdrawal symptoms.
Can Oprex affects my liver?
Oprex therapy is commonly associated with minor serum aminotransferase elevations and in very rare instances has been linked to clinically apparent acute liver injury
Can Oprex affects my heart ?
Oprex can cause a serious heart problem.