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Haloperidol

Brands and Forms

  • Haldol
    • tablet: 0.5mg scored, 1mg scored, 2mg scored, 5mg scored, 10mg scored, 20mg scored.
    • concentrate: 2mg/ml
    • solution: 1mg/ml
    • immediate-release injection: 5mg/ml
    • long-acting injection: 50mg Haloperidol as 70.5mg/ml haloperidol decanoate; 100mg Haloperidol as 141.04 mg/ml haloperidol decanoate.

Uses of Haloperidol

Haloperidol can be used in the treatment of Psychotic Disorders, Bipolar Disorder, and Tic Disorder. It can also be used for controlling acute agitation.

How Haloperidol Works

Haloperidol is a high-potency Typical Antipsychotic. It is an antagonist at dopamine D2 receptors.

Cautions when Using Haloperidol

In elderly individuals with Dementia, use of Antipsychotics has been associated with increased rates of sudden death. It is unclear whether the antipsychotic use is a cause, or simply a marker, of deteriorating health in these individuals.

Individuals with Parkinson disease or Lewy-Body Dementia may have increased sensitivity to Haloperidol, which may manifest as confusion, obtundation, severe extrapyramidal symptoms, and neuroleptic malignant syndrome.

Use with caution in patients with cardiovascular disease or mitral insufficiency, glaucoma, seizure disorders, or prior brain damage.

Haloperidol carries a significantly higher risk of causing extrapyramidal side-effects than the Atypical Antipsychotics.

Use caution when combining this medication with other CNS depressants.

People taking this medication should avoid extreme heat exposure.

Dosing of Haloperidol

For much of the history of its use, the therapeutic range of Haloperidol was considered to be about 10-40mg/day, and in some cases up to 100mg/day.

However, recent studies have suggested that many people can respond to much lower doses, in the range of 2-5mg/day, and that at these low doses there are fewer side-effects, including less extrapyramidal side-effects, and fewer clinical differences between it and Atypical Antipsychotics [ref].

It is thus recommended to initiate treatment at a dose of 1-5mg one daily at bedtime. If after a week there is no therapeutic effect, the dose can be increased in increments of 1-5mg every few days, depending on clinical response.

The long-acting decanoate form of Haloperidol is an injection that can be given once every four weeks. The dose is about 10-15 times the previous oral dose if the individual was taking low doses of 10mg/day or less. Initial dose may be as high as 20 times the previous oral dose for individuals maintained on higher oral doses. The maximum single dose is 100mg. If more is required, then the remainder can be given 3-7 days later.

When wanting to stop Haloperidol, the dose should be gradually reduced over a period of 6-8 weeks.

Onset of action

Psychotic symptoms can improve within 1 week of use, but full therapeutic effect may take several weeks. If there is no significant effect after 4-6 weeks, including 2 weeks at a dose above 10mg/day, then it may not work at all.

Acute agitation can improve after a single dose.

Kidney impairment

Use with caution.

Liver impairment

Use with caution.

Side-effects of Haloperidol

Below is a list of most of the reported side-effects of Haloperidol. Most of these side-effects occur in only a minority of individuals, and many also resolve with time while the medication is continued.

Cardiovascular: orthostatic hypotension; hypertension; tachycardia; ECG changes.

Central Nervous System: extrapyramidal symptoms (dose-related); insomnia; restlessness; drowsiness; lethargy; headache; confusion; vertigo; muscle spasms; opisthotonos; hyperreflexia; seizures (rare).

Dermatologic: maculopapular and acneiform skin reactions; photosensitivity; hair loss.

Endocrine: Weight gain; elevated or lowered blood sugar; elevated prolactin; breast pain, enlargement, or milk production in men and women; trouble conceiving; loss of libido; erectile dysfunction; hyponatremia.

Eyes, Ears, Nose and Throat: cataracts; retinopathy; visual disturbances; dilated pupils; increased intraocular pressure; nasal congestion.

Gastrointestinal: dyspepsia; appetite loss; diarrhea; hypersalivation; nausea; vomiting; dry mouth; intestinal obstruction (rare); impaired liver function (rare).

Genitourinary: menstrual irregularities; impotence; sexual dysfunction; priapism; urinary hesitancy or retention.

Hematologic: leukopenia (rare); leukocytosis (rare); anemia (rare); agranulocytosis (very rare).

Musculoskeletal: muscle stiffness; muscle pains; muscle spasms; neuroleptic malignant syndrome (rare).

Psychiatric: anxiety; agitation; depressed mood; loss of interest and motivation.

Respiratory: laryngospasm; bronchospasm; increased depth of respiration; bronchopneumonia.

Common side-effects of Haloperidol

Sedation, fatigue, insomnia, constipation, dry mouth, weight gain, urinary retention, blurred vision, extrapyramidal symptoms, breast enlargement.

Rare but serious side-effects of note of Haloperidol

Haloperidol overdose

Sedation, low blood pressure, extrapyramidal symptoms, respiratory depression, coma. Can be fatal.

Haloperidol and pregnancy

Category C: some animal studies show adverse effects at very high doses, but no controlled human studies have been done; should only be used in pregnancy if clearly needed and if benefits outweigh potential risks.

Medical Monitoring for Haloperidol

Monitoring for weight gain requires the following measures to be taken prior to starting the medication, then monthly for the first 3 months of use, and then every 3 months:

  • Body Mass Index (BMI)
  • waistline circumference at umbilicus
  • blood pressure
  • fasting blood glucose
  • fasting blood lipids and cholesterol

A complete blood count, liver function tests and electrolytes should be measured a few weeks after starting the medication, and then every 6 months to monitor for leukopenia, liver impairment and hyponatremia.

To monitor for elevated prolactin, prolactin levels should be measured prior to starting the medication, and then one month after every dose increase.

Patients should also receive physical examinations on a regular basis in order to detect and document the presence of extrapyramidal symptoms.

Drug Interactions with Haloperidol

  • Additive effects may occur if combined with other CNS depressants
  • Haloperidol can increase the effects of antihypertensives, except Guanethidine, whose actions can be reduced by Haloperidol.
  • Haloperidol can reduce the effects of anticoagulants.
  • Haloperidol blood concentrations can be lowered by Rifampin.
  • Risk of neuroleptic malignant syndrome increases when Haloperidol is combined with other antipsychotics or with Lithium.