Philidol

Philidol Uses, Dosage, Side Effects, Food Interaction and all others data.

Philidol 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 Philidol
Availability Prescription only
Generic Haloperidol
Haloperidol Other Names Haloperidol, Haloperidolum
Related Drugs hydroxyzine, lorazepam, ondansetron, diazepam, Zofran, meclizine, promethazine, risperidone, Ativan, Depakote
Type Tablet
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 Intra Life Pvt Ltd
Available Country India
Last Updated: September 19, 2023 at 7:00 am
Philidol
Philidol

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

Philidol 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 Philidol 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

Philidol 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. Philidol should only be used with great caution in patients with disturbed thyroid function.

Interaction

Philidol 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. Philidol 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. Philidol 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). Philidol 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.

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

Philidol 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. Philidol 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).

Philidol 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 Philidol

Philidol contains Haloperidol see full prescribing information from innovator Philidol Monograph, Philidol MSDS, Philidol FDA label

FAQ

What is Philidol used for?

Philidol 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. Philidol is also used to control motor and speech tics in people with. Philidol may also be used for purposes not listed in this medication guide.

How safe is Philidol?

Many people using this Philidol do not have serious side effects. In rare cases, Philidol 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 Philidol work?

Philidol works by inhibiting the effects of dopamine and increasing its turnover.

What are the common side effects of Philidol?

The common side effects of Philidol are include;

  • dry mouth.
  • increased saliva.
  • blurred vision.
  • loss of appetite.
  • constipation.
  • diarrhea.
  • heartburn.
  • nausea.

Is Philidol safe during pregnancy?

Philidol is rated FDA Pregnancy Category C. In animal studies, Philidol rarely induced fetal malformations. In humans, the amount of placental passage shown by the drug is 65.5% ± 40.3%.

Is Philidol safe during breastfeeding?

Philidol 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 Philidol?

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 Philidol.

Can I drive after taking Philidol?

Philidol 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 Philidol daily?

It is usually taken two or three times a day. Take Philidol at around the same times every day.

When should be taken of Philidol?

You can take Philidol before or after your meals. Swallow the dose with a drink of water.

How long does Philidol take to work?

Philidol 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 Philidol stay in my system?

The half-life of the drug is approximately 3 weeks.

Can I take Philidol every day?

Philidol should be taken every day as ordered by your healthcare provider.

How do I stop taking Philidol?

Do not stop receiving Philidol suddenly without asking your doctor. You may need to slowly decrease your dose before stopping it completely.

When should I stop taking Philidol?

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 Philidol right away and get medical help.

Who should not take Philidol?

You should not use Philidol if you are allergic to it, or if you have: Parkinson's disease; or. certain conditions that affect your central nervous system. Philidol 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 Philidol can be fatal.

Can Philidol affect my heart?

Philidol 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 Philidol?

You should not stop taking Philidol abruptly as it may lead to the development of withdrawal symptoms.

Can Philidol affects my liver?

Philidol therapy is commonly associated with minor serum aminotransferase elevations and in very rare instances has been linked to clinically apparent acute liver injury

Can Philidol affects my heart ?

Philidol can cause a serious heart problem.

*** Taking medicines without doctor's advice can cause long-term problems.
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