haloperidol

Actions and Spectrum: 

haloperidol is a potent antipsychotic medication that acts primarily by blocking dopamine receptors in the brain. Its actions and therapeutic spectrum include: 

• Antipsychotic effects: haloperidol is primarily used to treat psychosis, including schizophrenia and other psychotic disorders. It works by blocking dopamine receptors in the brain, which reduces the activity of dopaminergic neurons and decreases the intensity of psychotic symptoms, such as hallucinations, delusions, and disordered thinking. 
• Antiemetic effects: haloperidol is used to prevent and treat nausea and vomiting caused by chemotherapy, radiation therapy, and surgery. Its antiemetic effects are thought to be mediated through its actions on dopamine and serotonin receptors in the brainstem. 
• Agitation and aggression: haloperidol is used to treat agitation and aggression associated with various conditions, including dementia, delirium, and acute behavioral disturbances in psychiatric patients. It is effective in calming agitated or aggressive behavior and preventing the risk of harm to the patient or others. 
• Tourette’s syndrome: haloperidol is used to treat the motor and vocal tics associated with Tourette’s syndrome, a neurological disorder characterized by involuntary movements and vocalizations. 
• Mania and bipolar disorder: haloperidol may be used in the acute treatment of mania and bipolar disorder, although it is generally reserved for patients who do not respond to other medications. 

DRUG INTERACTION

Contraindicated  

Serious Use Alternative  

Monitor Closely  

Minor  

Frequency not defined 

Akathisia 

Dystonia 

Parkinsonism 

Sedation 

Weight gain 

Anxiety 

Anorexia 

Dyspepsia 

Lens opacities 

Priapism  

Black Box Warning: 

Antipsychotic drugs have been associated with an increased risk of death in elderly patients with dementia-related psychosis. In 2005, the US Food and Drug Administration (FDA) issued a black box warning regarding the use of atypical antipsychotics in elderly patients with dementia-related psychosis due to an increased risk of mortality.

The warning indicated that these drugs are not approved for the treatment of dementia-related psychosis. Subsequently, clinical studies have shown that the risk of death is highest during the first few months of treatment with antipsychotic drugs, and that the risk may be higher with the use of some atypical antipsychotic drugs compared to others.

As a result, the use of antipsychotic drugs in elderly patients with dementia-related psychosis is generally discouraged unless the patient is experiencing severe symptoms that significantly impair their quality of life, and other treatment options have been exhausted. 

Contraindication/Caution: 

There are several contraindications and precautions associated with the use of haloperidol, including: 

• Hypersensitivity to haloperidol or any of its components: Patients who have a known hypersensitivity to haloperidol or any of its components should not use this medication. 
• CNS depression: haloperidol can cause central nervous system (CNS) depression, which can be dangerous in patients with conditions such as head injury, coma, or severe respiratory depression. 
• Parkinson’s disease: haloperidol can worsen symptoms of Parkinson’s disease, including tremors and rigidity. 
• Seizure disorders: haloperidol can lower the seizure threshold, which can increase the risk of seizures in patients with a history of seizure disorders. 
• Cardiovascular disease: haloperidol can cause changes in heart rate and rhythm, which can be dangerous in patients with underlying cardiovascular disease. 
• Liver disease: haloperidol is primarily metabolized in the liver, and patients with liver disease may be at an increased risk of adverse effects. 
• Pregnancy and lactation: haloperidol should only be used during pregnancy and lactation if the potential benefits outweigh the potential risks to the fetus or infant. 

Pregnancy consideration:  

No well-controlled studies are reported in pregnant women, but cases of limb malformations are observed  

Breastfeeding warnings:  

haloperidol is known for its excretion in breastmilk. Lactating females should not nurse the infant during treatment 

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no affirmation of risk to the fetus found in animal reproduction studies, and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a product in humans; Pregnant women must take care of the potential risks. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms. However, despite potential dangers may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits. The drug is not for pregnant women. 
• Category N: No data is available for the drug under this category. 

Pharmacology: 

haloperidol is a medication that belongs to the class of drugs called antipsychotics. It is used to treat various psychiatric disorders, including schizophrenia, mania, and Tourette’s syndrome. 

Pharmacologically, haloperidol works by blocking dopamine receptors in the brain. Dopamine is a neurotransmitter that plays a key role in regulating mood, behavior, and movement. By blocking dopamine receptors, haloperidol reduces the activity of dopamine in the brain, which can help to alleviate the symptoms of psychosis. 

haloperidol is primarily metabolized by the liver and excreted in the urine. The drug has a half-life of approximately 20 hours, meaning that it takes about 20 hours for half of the drug to be eliminated from the body. 

Common side effects of haloperidol include drowsiness, dizziness, dry mouth, constipation, and blurred vision. More serious side effects may include tardive dyskinesia (a movement disorder), neuroleptic malignant syndrome (a potentially life-threatening condition), and an increased risk of stroke in elderly patients with dementia. 

Pharmacodynamics: 

The pharmacodynamics of haloperidol involves its mechanism of action, effects on neurotransmitters, and its therapeutic and side effects. 

haloperidol acts primarily as a dopamine receptor antagonist, specifically at D2 dopamine receptors in the brain. It blocks the binding of dopamine to its receptors, reducing the activity of dopamine in certain areas of the brain. This is believed to be the basis for its antipsychotic effects. 

In addition to its effects on dopamine, haloperidol also has activity at other receptors in the brain, including serotonin, histamine, and adrenergic receptors. This can lead to side effects such as sedation, orthostatic hypotension, and weight gain. 

Pharmacokinetics: 

Absorption 

The bioavailability is 60-70% 

Onset of action takes place in 30-60 minutes 

Duration of action is 2-4 weeks  

Peak plasma concentration is achieved in 2-6 hours (oral); 10-20 minutes(intramuscular); and 6-7 days (decanoate) 

Distribution 

Protein bound is 90% 

The volume of distribution is 8-18 L/kg 

Metabolism 

The drug is metabolized by hepatic P450 enzyme CYP3A4 

The metabolites formed are Hydroxy haloperidol 

The enzymes inhibited are CYP2D6 

Elimination and Excretion 

The half-life is achieved in 18 hours 

The drug is excreted 30% in urine and 15% in feces  

Administration 

haloperidol is typically administered orally, either as a tablet or a liquid. The medication can be taken with or without food, although taking it with food may help to reduce gastrointestinal side effects. 

The dose of haloperidol will vary depending on the condition being treated and the individual patient’s response to the medication. The medication is usually started at a low dose and gradually increased as needed, based on the patient’s symptoms and tolerability. 

In addition to oral administration, haloperidol is also available in injectable form for use in emergency situations, such as acute psychosis or agitation. The injectable form can be given intramuscularly (into a muscle) or intravenously (into a vein). 

Patient information leaflet 

Generic Name: haloperidol 

Pronounced: halo-peri-dol 

Why do we use haloperidol? 

haloperidol is used to treat a variety of psychiatric disorders, including schizophrenia, mania, and Tourette’s syndrome. It is classified as a typical antipsychotic medication and works by blocking dopamine receptors in the brain. 

Schizophrenia is a chronic mental disorder characterized by a range of symptoms, including delusions, hallucinations, disorganized thinking, and abnormal motor behavior. haloperidol is effective in treating the positive symptoms of schizophrenia, such as hallucinations and delusions. 

Mania is a symptom of bipolar disorder characterized by episodes of elevated, expansive, or irritable mood, along with increased activity and energy levels. Haloperidol is sometimes used in conjunction with other medications to treat mania. 

Tourette’s syndrome is a neurological disorder characterized by repetitive, involuntary movements and vocalizations called tics. haloperidol can be used to help reduce the frequency and severity of tics. 

In addition to these specific conditions, haloperidol is sometimes used in emergency settings to control agitation, aggression, and psychosis. It may also be used to manage symptoms associated with dementia in older adults.