Haloperidol is a typical antipsychotic

Typical antipsychotic

Typical antipsychotics are a class of antipsychotic drugs first developed in the 1950s and used to treat psychosis...

. It is in the butyrophenone

Butyrophenone

Butyrophenone is a chemical compound ; some of its derivatives are used to treat various psychiatric disorders such as schizophrenia, as well as acting as antiemetics....

 class of antipsychotic

Antipsychotic

An antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...

 medications and has pharmacological effects

Pharmacology

Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...

 similar to the phenothiazine

Phenothiazine

Phenothiazine is an organic compound that occurs in various antipsychotic and antihistaminic drugs. It has the formula S2NH. This yellow tricyclic compound is soluble in acetic acid, benzene, and ether. The compound is related to the thiazine-class of heterocyclic compounds...

s.

Haloperidol is an older antipsychotic used in the treatment of schizophrenia

Schizophrenia

Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

 and, more acutely, in the treatment of acute psychotic

Psychosis

Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...

 states and delirium

Delirium

Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...

. A long-acting decanoate ester

Ester

Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

 is used as an injection given every 4 weeks to people with schizophrenia

Schizophrenia

Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

 or related illnesses who have a poor compliance with medication and suffer frequent relapses of illness, or to overcome the drawbacks inherent to its orally administered counterpart that burst dosage increases risk or intensity of side effects.