Haldol (haloperidol) is a first-generation (typical) antipsychotic medication belonging to the butyrophenone class. It is a high-potency antipsychotic agent primarily indicated for the management of manifestations of psychotic disorders, including schizophrenia. It is also used for the control of tics and vocal utterances in Tourette’s disorder and may be employed for severe behavioral problems in children. Haldol functions primarily as a dopamine D2 receptor antagonist, exerting its therapeutic effects in the mesolimbic pathway while its extrapyramidal side effects are largely due to nigrostriatal pathway blockade. Its efficacy, well-established pharmacokinetic profile, and availability in multiple formulations make it a cornerstone in acute and maintenance psychiatric treatment protocols.

Features

• Active Ingredient: Haloperidol
• Drug Class: First-Generation (Typical) Antipsychotic
• Available Formulations: Oral tablets, oral concentrate solution, short-acting intramuscular (IM) injection, long-acting decanoate (IM) injection
• Receptor Affinity: Potent dopamine D2 receptor antagonist; also exhibits antagonism at alpha-1 adrenergic, histaminic H1, and muscarinic receptors
• Half-Life: Oral: ~24 hours; Haloperidol Decanoate: ~3 weeks
• Metabolism: Primarily hepatic via CYP3A4 and to a lesser extent CYP2D6

Benefits

• Provides rapid and effective control of positive psychotic symptoms such as hallucinations, delusions, and thought disorder.
• Offers a reliable option for the acute management of severe agitation and aggression in emergency settings via IM formulation.
• The long-acting decanoate injection enhances treatment adherence and provides stable plasma levels, reducing the risk of relapse in maintenance therapy.
• Effective in managing the motor and vocal tics associated with Tourette’s syndrome.
• Can be a cost-effective antipsychotic option within formularies.
• Possesses antiemetic properties due to its action on the chemoreceptor trigger zone.

Common use

Haldol is primarily prescribed for the treatment of schizophrenia. It is also commonly used to manage acute psychotic episodes and severe agitation across various diagnostic categories. In clinical practice, it is frequently employed in hospital emergency departments and inpatient psychiatric units for rapid tranquilization. Its use extends to the treatment of Tourette’s disorder, particularly for patients who do not respond adequately to first-line treatments. It is sometimes used off-label for the management of severe nausea and vomiting, and for delirium in hospital settings.

Dosage and direction

Dosage must be individualized based on symptom severity, patient age, clinical response, and tolerability.

Oral (Tablets/Oral Solution):

• Adults (Psychosis): Initial dose is often 0.5 mg to 5 mg, 2 or 3 times daily. Dose may be adjusted upward, usually at 3- to 5-day intervals, based on response. The usual maintenance dose range is 5 mg to 20 mg daily, though some patients may require higher doses. The total daily dose should be divided into 2 or 3 administrations.
• Elderly/Debilitated: Start with 0.5 mg to 2.0 mg daily in divided doses; increase gradually as needed and tolerated.
• Children (Behavioral Disorders/Tourette’s): 0.05 mg/kg/day to 0.075 mg/kg/day in 2 or 3 divided doses. Not recommended for children under 3 years.

Intramuscular (IM) Injection (Short-Acting):

• Acute Agitation: Initial dose of 2 mg to 5 mg, which may be repeated every 60 minutes, or as needed. The frequency of administration should be reduced to every 4 to 8 hours once control is achieved.

Haloperidol Decanoate (Long-Acting Injection):

• Initiation should be based on stabilization on oral haloperidol. The initial decanoate dose is generally 10 to 20 times the previous stable daily oral dose, administered every 4 weeks. The dose and dosing interval must be carefully titrated based on clinical response. The maximum recommended dose is 100 mg per injection.

Direction: Oral formulations can be taken with or without food. The oral concentrate must be diluted with water, juice, or a soft drink before administration. IM injections should be administered deeply into a large muscle mass.

Precautions

• Extrapyramidal Symptoms (EPS): Haldol carries a significant risk of acute dystonia, akathisia, parkinsonism, and tardive dyskinesia. Patients should be monitored closely for these movement disorders.
• Neuroleptic Malignant Syndrome (NMS): A rare but potentially fatal syndrome characterized by hyperpyrexia, muscle rigidity, altered mental status, and autonomic instability. Requires immediate discontinuation of the drug and intensive medical treatment.
• QT Prolongation: Haldol can prolong the QT interval on an electrocardiogram (ECG), which may increase the risk of serious cardiac arrhythmias, including Torsades de Pointes. Use with caution in patients with cardiac disease or electrolyte imbalance. Baseline and periodic ECGs may be warranted.
• Cognition and Sedation: May impair mental and/or physical abilities, especially during dose initiation. Patients should be cautioned about operating hazardous machinery or driving.
• Temperature Regulation: May disrupt the body’s ability to reduce core body temperature; caution is advised in patients exposed to extreme heat.
• Seizures: May lower the seizure threshold; use with caution in patients with a history of seizure disorders.
• Elderly Patients with Dementia-Related Psychosis: There is an increased risk of death and cerebrovascular adverse events in this population. Haldol is not approved for this use.

Contraindications

• Known hypersensitivity to haloperidol or any component of the formulation.
• Patients with severe central nervous system depression or comatose states.
• Patients with Parkinson’s disease or dementia with Lewy bodies (due to extreme sensitivity to EPS).
• Use is contraindicated in patients with known severe cardiac instability (e.g., recent acute myocardial infarction, uncompensated heart failure, significant QT prolongation, or history of significant arrhythmia).

Possible side effect

Side effects are dose-related and often involve the central nervous and endocrine systems.

Very Common/Common:

• Extrapyramidal symptoms (akathisia, dystonia, tremor, rigidity)
• Sedation, drowsiness, insomnia
• Headache, dizziness
• Hyperprolactinemia (leading to galactorrhea, gynecomastia, sexual dysfunction)
• Dry mouth, blurred vision, constipation
• Weight gain

Less Common/Serious:

• Tardive dyskinesia (often irreversible)
• Neuroleptic Malignant Syndrome (NMS)
• QT prolongation and cardiac arrhythmias
• Orthostatic hypotension
• Seizures
• Leukopenia, neutropenia, agranulocytosis
• Jaundice, liver enzyme alterations

Drug interaction

Haldol is subject to numerous significant drug interactions, primarily due to its metabolism by CYP enzymes and its pharmacodynamic effects.

• CNS Depressants (e.g., alcohol, benzodiazepines, opioids): Concomitant use can potentiate sedation and respiratory depression.
• QT-Prolonging Agents (e.g., antiarrhythmics like amiodarone, antibiotics like erythromycin, antidepressants like citalopram): Concomitant use significantly increases the risk of life-threatening arrhythmias.
• Enzyme Inducers (e.g., carbamazepine, rifampin, phenytoin): May increase the metabolism of haloperidol, reducing its plasma levels and efficacy.
• Enzyme Inhibitors (e.g., ketoconazole, itraconazole, fluoxetine, paroxetine): May decrease the metabolism of haloperidol, leading to increased plasma levels and a higher risk of toxicity and side effects.
• Anticholinergic Agents (e.g., benztropine, diphenhydramine): May be used to treat EPS but can also exacerbate other side effects like constipation and blurred vision. They may also reduce the efficacy of haloperidol by opposing its dopamine-blocking effects in the striatum.
• Levodopa and Dopamine Agonists: Haldol may antagonize the effects of these drugs.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped and the regular dosing schedule resumed. Do not double the dose to make up for a missed one. For patients on a long-acting decanoate injection, contact the prescribing physician if an appointment is missed to reschedule as soon as possible.

Overdose

Overdose is characterized by an exaggeration of known pharmacological effects, most seriously severe EPS, hypotension, sedation, and QT prolongation. Other symptoms may include agitation, restlessness, seizures, and cardiac arrhythmias. Management is supportive and symptomatic. There is no specific antidote. Ensure a patent airway and assist ventilation if necessary. ECG monitoring is essential. Management of severe EPS may require anticholinergic agents (e.g., benztropine). Hemodialysis is not effective due to high protein binding and large volume of distribution.

Storage

• Store at controlled room temperature (20°C to 25°C or 68°F to 77°F). Excursions are permitted between 15°C and 30°C (59°F and 86°F).
• Protect from light.
• Keep the oral concentrate in the original container. Do not freeze.
• Keep all medications out of the reach of children and pets.

Disclaimer

This information is for educational and informational purposes only and does not constitute medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The author and publisher are not responsible for any specific health or allergy needs that may require medical supervision and are not liable for any damages or negative consequences from any treatment, action, application, or preparation, to any person reading or following the information in this document.

Reviews

• “Haldol remains a gold-standard for rapid control of acute agitation in the ER. Its predictable pharmacokinetics and availability in IM form are invaluable in crisis situations.” - Board-Certified Emergency Psychiatrist
• “While the side effect profile, particularly EPS and TD, is a significant concern, the decanoate formulation is a lifesaver for non-adherent patients with chronic schizophrenia, providing consistent therapeutic levels and preventing relapse.” - Clinical Pharmacist, Inpatient Psychiatry
• “A powerful tool, but requires careful titration and vigilant monitoring for movement disorders and cardiac effects. Not a first-line choice for all patients, but indispensable for certain clinical presentations.” - Consultant Psychiatrist
• “Its efficacy in treating refractory Tourette’s tics is well-documented, though we always start with the lowest possible dose due to the high risk of side effects in the pediatric population.” - Child Neurologist