Haloperidol (Intramuscular)

Generic name: Haloperidol

Drug class: Typical antipsychotic

Dosage form: Intramuscular injection

Root of administration: Intramuscular

Dose: For acute agitation or psychosis, the typical intramuscular dose is 2 to 5 mg, which may be repeated every 4 to 8 hours as needed. For maintenance therapy, haloperidol decanoate is administered intramuscularly every 4 weeks, with doses ranging from 50 mg to 100 mg, depending on individual patient needs.

Mechanism of action: Haloperidol is a high-potency typical antipsychotic that exhibits high-affinity dopamine D₂ receptor antagonism and slow receptor dissociation kinetics. It binds preferentially to D₂ and α₁ receptors at low doses, and to 5-HT₂ receptors at higher doses, which underlies its effects on both positive and negative symptoms of schizophrenia.

Drug usage cases:

• Acute psychosis
• Schizophrenia
• Acute mania in bipolar disorder
• Delirium
• Agitation
• Acute psychosis
• Hallucinations from alcohol withdrawal
• Tourette syndrome (for severe tics)
• Adjunctive treatment of alcohol and opioid withdrawal
• Hyperactive delirium
• Hyperactivity and aggression in children and adolescents
• Severe behavioral disorders in children and adolescents
• Intractable hiccups
• Neurological disorders, including tic disorders and chorea

Drug contraindications:

• Hypersensitivity to haloperidol or any of its components
• Comatose states
• Parkinson’s disease
• Severe central nervous system depression
• Severe cardiovascular disorders
• Prolonged QT interval
• Severe hypokalemia or hypomagnesemia
• History of neuroleptic malignant syndrome
• Concurrent use with other QT-prolonging drugs

Side effects:

• Extrapyramidal symptoms (EPS) including akathisia, dystonia, and parkinsonism
• Tardive dyskinesia
• Neuroleptic malignant syndrome
• QT interval prolongation
• Hypotension
• Anticholinergic effects such as blurred vision, constipation, and dry mouth
• Weight gain
• Elevated prolactin levels
• Sexual dysfunction
• Photosensitivity
• Seizures
• Elevated liver enzymes
• Leukopenia or neutropenia

Warnings:

• Monitor for signs of neuroleptic malignant syndrome
• Regularly assess for tardive dyskinesia, especially during long-term therapy
• Monitor ECG for QT interval prolongation
• Use caution in patients with cardiovascular disease
• Monitor for signs of extrapyramidal symptoms
• Assess for signs of hyperprolactinemia
• Monitor weight and metabolic parameters regularly
• Use caution in elderly patients due to increased sensitivity
• Assess for signs of photosensitivity
• Monitor for signs of leukopenia or neutropenia

Use during pregnancy or breastfeeding: Haloperidol is classified as a Category C drug during pregnancy, indicating that risk to the fetus cannot be ruled out. It should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Haloperidol is excreted in breast milk and may cause adverse effects in nursing infants; therefore, it is generally contraindicated during breastfeeding.