Generic Name

Haloperidol

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Classification

FDA Approved Indications

• Schizophrenia
• Acute psychosis
• Tourette's disorder
• Hiccups (off-label)

Mechanism of Action

Haloperidol works by blocking dopamine D2 receptors in the brain, which helps to reduce psychotic symptoms such as hallucinations and delusions.

Dosage and Administration

Adult: Dosing varies by indication; for schizophrenia, typically 0.5 to 2 mg orally two to three times daily, titrating based on response. For acute agitation, higher initial doses may be used. Patients should be monitored for efficacy and side effects.

Pediatric: Use in children is typically limited and dose should be carefully titrated under specialist supervision.

Geriatric: Start at lower doses due to increased sensitivity to side effects, particularly extrapyramidal symptoms and orthostatic hypotension.

Renal Impairment: No specific dose adjustment required, but monitor for side effects.

Hepatic Impairment: Use with caution; dose adjustments may be necessary.

Pharmacokinetics

Absorption: Well-absorbed orally, with bioavailability of approximately 60-70%.

Distribution: Widely distributed in body tissues, crosses blood-brain barrier; protein binding around 92%.

Metabolism: Metabolized extensively in the liver via CYP3A4 and other enzymes.

Excretion: Primarily excreted via urine and feces; inactive metabolites.

Half Life: Approximately 12-36 hours, allowing for once or twice daily dosing.

Contraindications

• Comcomitant use with or within 14 days of MAO inhibitors.
• History of hypersensitivity to haloperidol or other butyrophenones.

Precautions

• Increase monitoring for EPS, tardive dyskinesia, neuroleptic malignant syndrome, cardiac arrhythmias.
• Use with caution in elderly patients with dementia-related psychosis due to increased risk of death.
• Pregnancy Category C; use only if potential benefit justifies risk.

Adverse Reactions - Common

• Extrapyramidal symptoms ( dystonia, akathisia, Parkinsonism) (Common)
• Sedation (Common)
• Weight gain (Common)
• Dry mouth (Common)

Adverse Reactions - Serious

• Neuroleptic malignant syndrome (NMS) (Rare)
• QT prolongation, torsades de pointes (Rare)
• Leukopenia, neutropenia, agranulocytosis (Very rare)
• Sudden death in elderly with dementia-related psychosis (Rare)

Drug-Drug Interactions

• CNS depressants (additive sedative effect)
• Other QT-prolonging agents (risk of cardiac arrhythmias)
• Anticholinergic medications (exacerbation of anticholinergic effects)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Advise about possible side effects, including EPS and tardive dyskinesia, and the importance of regular monitoring.
• Warn about the potential for drowsiness and the need to avoid alcohol.
• Explain the importance of adherence and not stopping medication abruptly.

Special Considerations

Black Box Warnings:

• Increased mortality in elderly patients with dementia-related psychosis.
• Tardive dyskinesia risk increases with long-term use.

Genetic Factors: Pharmacogenetic variations in CYP2D6 can alter drug metabolism.

Lab Test Interference: Potential for false-positive results in certain laboratory tests, including prolactin levels.

Overdose Management

Signs/Symptoms: Extrapyramidal symptoms, hypotension, sedation, QT prolongation, coma.

Treatment: Supportive care, gastric lavage if early, activated charcoal if appropriate, electrolyte stabilization, management of arrhythmias, and intensive symptomatic care.

Storage and Handling

Storage: Store at room temperature, away from light and moisture.

Stability: Stable for 24 months when stored properly.