Haloperidol

Haloperidol

Definition

Haloperidol is a major tranquilizer. It is used to treat psychoses, senile dementia , Tourette's syndrome, and certain serious behavioral disorders in children. In the United States it is sold under the brand name Haldol.

Purpose

Haloperidol is used to control symptoms of psychotic disorders, such as schizophrenia . It is also used for controlling tics and inappropriate vocalizations associated with Tourette's syndrome in both children and adults.

In children, haloperidol is occasionally used to treat severe behavior problems such as combativeness and extreme outbursts that that occur without immediate provocation. Occasionally it is used for short-term treatment of children who display excessive motor activity with accompanying difficulty in attention, aggression, impulse control, mood changes, and coping with frustration. Haloperidol is used only after psychotherapy and other medications have been tried and found to be unsuccessful.

Description

Haloperidol is a major tranquilizer, and can be administered as a pill or by intramuscular injection (a shot).

The precise way in which haloperidol helps control symptoms associated with psychoses or dementia has not yet been clearly established.

Recommended dosage

For adults, the recommended initial dosage of haloperidol is 0.5 –5.0 mg two or three times each day. The initial dosage depends on the severity of the symptoms in the person being treated. All people taking haloperidol must be carefully monitored to establish an individualized dosage. Physicians have found that there is great variability in the amount of haloperidol required to control symptoms.

Children require smaller dosages of haloperidol than do adults. The recommended initial dosage of haloperidol for controlling psychotic symptoms in children is 0.5–2.0 mg two or three times each day. The recommended dosage for controlling symptoms of Tourette's syndrome and other non-psychotic disorders is between 0.075 and 0.05 mg per kilogram of body weight per day. The total dosage is usually divided into two or three administrations per day. The goal of therapy is to use the smallest amount of haloperidol that will control symptoms. Children under age three should not take this drug.

Precautions

Haloperidol may cause low blood pressure (hypotension). For this reason people with heart and blood pressure problems should be carefully monitored while taking the drug. Haloperidol also increases the possibility of having seizures . People with a history of seizures or who are taking anticonvulsants (medication to control seizures) should take lower dosages of haloperidol and be closely monitored by a physician until a safe dosage is established. Haloperidol also interferes with the action of the anticoagulant (blood-thinning) drug phenindione.

Haloperidol may increase the action of central nervous system depressants such as anesthetics, alcohol, and opiates (some pain killers and sleeping pills). It may also decrease the time required to change from mania to depression among persons with bipolar disorder (also known as manic-depressive disorder).

Side effects

Haloperidol has the potential to produce a serious side effect called tardive dyskinesia . This syndrome consists of involuntary, uncoordinated movements that may not disappear or may only partially improve after the drug is stopped. Tardive dyskinesia involves involuntary movements of the tongue, jaw, mouth or face or other groups of skeletal muscles. These side effects may appear after people have stopped taking haloperidol. The chance of developing tardive dyskinesia increases with increasing age and with increasing dosage of haloperidol. Women are at greater risk than men for developing tardive dyskinesia. There is no known effective treatment for tardive dyskinesia, although gradual (but rarely complete) improvement may occur over a long period.

Haloperidol use may lead to the development of symptoms that resemble Parkinson's disease, but that are not caused by Parkinson's. These symptoms may include a taut or mask-like expression on the face, drooling, tremors, pill-rolling motions in the hands, cogwheel rigidity (abnormal rigidity in muscles, characterized by jerky movements when the muscle is passively stretched), and a shuffling gait. Taking the anti-Parkinson drugs benztropine mesylate or trihexyphenidyl hydrochloride along with haloperidol help to control these symptoms. Medication to control Parkinsonian-like symptoms may have to be continued after haloperidol is stopped. This is due to different rates of elimination of these drugs from the body.

Other side effects of haloperidol include anxiety, restlessness, agitation, insomnia , headache, euphoria, drowsiness, depression, confusion, dizziness, and seizures. Unwanted or unexpected effects associated with the use of haloperidol have been reported for virtually all organ systems in the body. Although numerous, such side effects are relatively uncommon.

Interactions

The simultaneous use of haloperidol and lithium, a common treatment for bipolar disorder, has been associated with an encephalopathic syndrome. People with this syndrome have symptoms of weakness, lethargy, fever, confusion, and high levels of white blood cells.

Haloperidol may increase the effect of central nervous system depressants such as anesthetics, opiates, and alcohol.

Resources

BOOKS

Adams, Michael and Norman Holland. Core Concepts in Pharmacology. Philadelphia: Lippincott-Raven, 1998.

Foreman, John C. and Torben Johansen. Textbook of Receptor Pharmacology. 2nd ed. Boca Raton, FL: CRC Press, 2002.

Page, Clive P., and Michael Murphy. Integrated Pharmacology. St. Louis: Mosby-Year Book, 2002.

Von Boxtel, Chris J., Budiono Santoso, and I. Ralph Edwards. Drug Benefits and Risks: International Textbook of Clinical Pharmacology. New York: John Wiley and Sons, 2001.

PERIODICALS

Arrants, J. " Intravenous haloperidol." Critical Care Nurse 21, no. 3 (2001): 19-20.

Harrison, A. M., R. A. Lugo, W. E. Lee, E. Appachi, D. Bourdakos, S. J. Davis, M. J. McHugh, and K. L. Weise. "The use of haloperidol in agitated critically ill children." Clinical Pediatrics (Philadelphia) 41, no. 1 (2002): 51-54.

Pisani F., G. Oteri, C. Costa, G. Di Raimondo, and R. Di Perri. "Effects of psychotropic drugs on seizure threshold." Drug Safety 25, no. 2 (2002): 91-110.

ORGANIZATIONS

American Academy of Clinical Toxicology. 777 East Park Drive, PO Box 8820, Harrisburg, PA 17105-8820. Phone: (717) 558-7750. Fax: (717) 558-7845. Web site: <http://www.clintox.org/index.html>.

American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211-2672. Phone: (913) 906-6000. Web site: <http://www.aafp.org/>.

American Medical Association. 515 N. State Street, Chicago, IL 60610. Phone: (312) 464-5000. Web site: <http://www.ama-assn.org/>.

American Psychiatric Association. 1400 K Street NW, Washington, DC 20005. Telephone: (888) 357-7924. Fax (202) 682-6850, Web site: <http://www.psych.org/>.

American Society for Clinical Pharmacology and Therapeutics. 528 North Washington Street, Alexandria, VA 22314. Telephone: (703) 836-6981. Fax: (703) 836-5223.

American Society for Pharmacology and Experimental Therapeutics. 9650 Rockville Pike, Bethesda, MD 20814-3995. Telephone: (301) 530-7060. Fax: (301) 530-7061. Web site: <http://www.aspet.org/>.

L. Fleming Fallon, Jr., M.D., Dr.P.H.