Haloperidol

Class

• Butyrophenone typical antipsychotic

Indications

• Schizophrenia

• Acute psychotic states and delirium

  • Schizoaffective disorder

  • Delusional disorders

• Ballism

• Tourette syndrome (a drug of choice)

• Occasionally as adjunctive therapy in mental retardation and the chorea of huntington disease

• Intractable hiccups

• ADHD

• Severe nausea and vomiting

Administration/Absorption

• Oral

• IM

• IV

Dosage

• • Plasma levels of 4 to 25 micrograms per liter are required for therapeutic action.

Distribution

• 92% protein bound

Mechanism

• Strong central antidopaminergic action

• Effective dopaminergic receptor blockage in the mesocortex and the limbic system of the brain

  • strong activity against delusions and hallucinations

• Blocks the dopaminergic action in the nigrostriatal pathways

  • Probable reason for the high frequency of extrapyramidal-motoric side effects (dystonias, akathisia, pseudoparkinsonism).

• Minor antihistaminic and anticholinergic properties

• Sedative properties

  • Strong action against psychomotor agitation due to a specific action in the limbic system

  • However, in some cases, haloperidol may worsen psychomotor agitation via its potent dopamine receptor antagonism

• The peripheral antidopaminergic effects

  • Account for its strong antiemetic activity

  • Also leads also to a relaxation of the gastric sphincter muscle and an increased release of the hormone prolactin

    • Possible emergence of breast enlargement and secretion of milk (galactorrhea) in both sexes

Excretion

• Plasma concentrations of haloperidol decanoate reach a peak at about 6 days after the injection, falling thereafter, with an approx. half-life of 3 weeks

• Liver metabolism

Side effects

• Strong early and late extrapyramidal side effects

• Akathisia

• Dry mouth

• Lethargy

• Muscle-stiffness, muscle-cramping, restlessness, tremors

• Rabbit syndrome

• weight-gain

• Depression, severe enough to result in suicide, is quite often seen during long-term treatment

• Symptoms of dystonia may occur in susceptible individuals during the first few days of treatment

• Neuroleptic malignant syndrome

• QT prolongation with sudden death

• Thromboembolic complications

Interactions

Contraindications

• Absolute

  • Preexisting coma, acute stroke

  • Severe intoxication with alcohol or other central depressant drugs

  • Known allergy against haloperidol or other butyrophenones or other drug ingredients

  • Known heart disease; when combined will tend towards cardiac arrest

• Special caution needed

  • Preexisting Parkinson's disease[23] or dementia with Lewy bodies

  • Patients at special risk for the development of QT prolongation

    • hypokalemia

    • concomitant use of other drugs causing QT prolongation)

  • Compromised liver-function

  • Patients with hyperthyreosis

  • IV injections: risk of hypotension or orthostatic collapse