Haloperidol is a traditional or conventional antipsychotic used to treat schizophrenia, mania and other forms of psychosis. It is a derivative of butyrophenone and it acts by blocking the effects of dopamine, a chemical in the brain that affects thinking, behavior and feelings.

Haloperidol was first discovered by Paul Janssen, the founder of a large pharmaceutical company in Belgium called Janssen Pharmaceutica. The company developed haloperidol in 1958 and the drug was entered into clinical trials later in the year. In 1967, the U.S. Food and Drug Administration approved haloperidol and it was then later marketed in the U.S. by McNeil Laboratories under the name Haldol.

Haloperidol is sold under the following trade names: Aloperidin, Bioperidolo, Brotopon, Dozic, Duraperidol (Germany), Einalon S, Eukystol, Haldol, Halosten, Keselan, Linton, Peluces, Serenace, Serenase, and Sigaperidol.

The drug is prescribed both as an oral medication and as intravenous and intramuscular injectable preparations. One injectable preparations is the long-acting decanoate ester, which is used to treat people with schizophrenia and related conditions who have had difficulty adhering to other medication plans. This can happen if patients have a poor understanding of their illness or because they forget to take their tablets. These patients often suffer frequent relapses of their condition as a result. Patients are administered one haloperidol injection every four weeks.

Haloperidol is used to treat a wide variety of mental illnesses. Aside from being used as a medication for schizophrenia, haloperidol is used to control acute psychosis, including psychosis induced by drugs such as LSD, amphetamines, ketamine, psilocybin and phencyclidine. It can help control the psychosis associated with high fever or metabolic disease and can reduce the agitation and confusion associated with cerebral sclerosis. Other uses include an adjunctive treatment in alcohol and opioid withdrawal and a treatment for some neurological disorders such as tics and Tourette syndrome. Chronic pain, severe hiccups and severe nausea and vomiting can also be relieved using haloperidol.