Haloperidol (Haldol) in the Treatment of Psychosis
One of the most commonly used typical antipsychotic medications is Haloperidol (Haldol). Haldol’s primary purpose is for the treatment of symptoms associated with Schizophrenia.  Haldol has been shown to provide effective sedation to patients with acute schizophrenic episodes. The secondary purpose is for the control of tics and verbal utterances of Tourette’s disorder.
Mechanism of Action
The active mechanism of Haldol is to block postsynaptic dopamine (D2) receptors in the mesolimbic system of the brain.
In the treatment of Schizophrenia and Tourette’s disorder, there are two methods of administration, oral and intramuscular (IM). With the treatment of moderate schizophrenia, the initial dose is commonly 0.5-2 mg every 12 hours. For severe schizophrenia, the dose is 3-5 mg every 12 hours without exceeding 30 mg per day. In the use of IM administration, the initial monthly dose is 10-20 times the daily oral dose without exceeding 100 mg. The maintenance dose is administered once a month, equaling to 10-15 times the daily oral dose.
In Tourette’s disorder, the initial oral dose is 0.5-2 mg every 8-12 hours. If the symptoms are severe, the dose increases to 3-5 mg every 8-12 hours. If the Tourette’s disorder is uncontrolled, the daily dose increases up to 100 mg daily.
The pharmacokinetics of Haldol depend on patient characteristics such as gender, age, weight, and race. The half-life of Haldol is commonly 14.5-36.7 hours. The half-life for chronic administration is 21 days. The average clearance time for Haldol is approximately 24.2 mL/minute. Haldol metabolizes in the liver by oxidizing N- dealkylation to piperidine metabolites and 4-fluorobenzoylpropionic acid. It is important for a physical therapist to understand the elimination rate of Haldol because it explains the prolonged effects of the drug and average timeline to monitor adverse effects.
In addition to the common adverse effects of typical antipsychotics, Haldol presents with withdrawal emergent neurological signs after discontinuation of the medication presented by dyskinetic movement distinguished by duration compared to tardive dyskinesia. Haldol’s contraindications is to refrain from use in patients with Parkinson’s, hypersensitivity to the drug, severe CNS depression or in a comatose state.
Physical Therapy Implications
Physical therapists should monitor vital signs during the session to better manage the potential for falls, unconsciousness, and hypotension. Physical therapists can develop interventions such as gait training and use of assistive devices for ambulatory issues. Physical therapists should monitor physiological changes in such as cardiovascular effects, tardive dyskinesia and neuroleptic malignant syndrome in elderly patients with dementia due to an increased mortality rate. 
For more information regarding Haldol, please visit the FDA's medication guide: Haldol
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