What is/are Haloperidol?
Haloperidol is a dopamine inverse agonist of the typical antipsychotic class of medications. It is a butyrophenone derivative and has pharmacological effects similar to the phenothiazines.
Haloperidol is an older antipsychotic used in the treatment of schizophrenia and acute psychotic states and delirium. A long-acting decanoate ester is used as an injection given every four weeks to people with schizophrenia or related illnesses who have poor adherence to medication regimens 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. In some countries, such as the United States of America, injections of antipsychotics such as haloperidol can be ordered by a court at the request of a psychiatrist. Haloperidol is sold under the tradenames Aloperidin, Bioperidolo, Brotopon, Dozic, Duraperidol (Germany), Einalon S, Eukystol, Haldol (common tradename in the US and UK), Halosten, Keselan, Linton, Peluces, Serenace and Sigaperidol.
A review of haloperidol found that while it may be marginally effective in treatment of symptoms associated with schizophrenia there is a high rate of adverse events. This conclusion may be overly generous as half of people did not complete the studies and some negative trials may have remained unpublished. It should only be used if other treatments are not a possibility.
It is also used in the control of the symptoms of:
- Acute psychosis, such as drug-induced psychosis caused by LSD, psilocybin, amphetamines, ketamine, and phencyclidine, and psychosis associated with high fever or metabolic disease
- Acute manic phases until the concomitantly given first-line drugs such as lithium or valproate are effective
- Hyperactivity, aggression
- Acute delirium
- Otherwise uncontrollable, severe behavioral disorders in children and adolescents
- Agitation and confusion associated with cerebral sclerosis
- Adjunctive treatment of alcohol and opioid withdrawal
- Treatment of severe nausea and emesis in postoperative and palliative care, especially for palliating adverse effects of radiation therapy and chemotherapy in oncology
- Treatment of neurological disorders, such as tic disorders, Tourette syndrome, and chorea
- Adjunctive treatment of severe chronic pain, always with analgesics
- Therapeutic trial in personality disorders, such as borderline personality disorder
- Treatment of intractable hiccups
- Also used in aquaculture to block dopamine receptors to enable GnrHA function for ovulation use in spawning fish
Some weeks or even months of treatment may be needed before a remission of schizophrenia is evident.
In some clinics, the use of atypical neuroleptics (e.g., clozapine, risperidone,olanzapine, or ziprasidone) is, in general, preferred over haloperidol, because these drugs have an appreciably lower incidence of extrapyramidal side effects. Each of these drugs, however, has its own spectrum of potentially serious side effects (e.g., agranulocytosis with clozapine, weight gain with increased risk of diabetes and of stroke). Atypical neuroleptics are also much more expensive and have recently been the subject of increasing controversy regarding their efficacy in comparison to older products and their side effects.
Haloperidol was considered indispensable for treating psychiatric emergency situations, although the newer atypical drugs have gained greater role in a number of situations as outlined in a series of consensus reviews published between 2001 and 2005. It is enrolled in the World Health OrganizationList of Essential Medicines.
As is common with typical neuroleptics, haloperidol is by far more active against "positive" psychotic symptoms (delusions, hallucinations, etc.) than against "negative" symptoms (social withdrawal, etc.).
A multiple-year study suggested this drug and other neuroleptic antipsychotic drugs commonly given to Alzheimer's patients with mild behavioural problems often make their condition worse that its withdrawal was even benefitial for some cognitive and functional measures.
Haloperidol is noted for its strong early and late extrapyramidal side effects. The risk of the face-disfiguring tardive dyskinesia is around 4% per year in younger patients. Other predisposing factors may be female gender, pre-existing affective disorder, and cerebral dysfunction. Akathisia often manifests itself with anxiety, dysphoria, and an inability to remain motionless. Other side effects include dry mouth, lethargy, restlessness of akathisia, muscle stiffness or cramping, restlessness, tremors, Rabbit syndrome, and weight gain; side effects like these are more likely to occur when the drug is given in high doses and/or during long-term treatment. Depression, severe enough to result in suicide, is quite often seen during long-term treatment. Care should be taken to detect and treat depression early in course. Sometimes the change from haloperidol to a mildly potent neuroleptic (e.g., chlorprothixene or chlorpromazine), together with appropriate antidepressant therapy, does help. Sedative and anticholinergic side effects occur more frequently in the elderly. The likelihood of one's experiencing one or more of these side effects is quite high regardless of age and gender, especially with prolonged use.
Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment. Dystonic symptoms include spasm of the neck muscles sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first-generation antipsychotic drugs. An elevated risk of acute dystonia is observed in males and younger age groups.
The potentially fatal neuroleptic malignant syndrome (NMS) is a significant possible side effect. Haloperidol and fluphenazine cause NMS most often. NMS involves fever and other symptoms. Allergic and toxic side effects occur. Skin rash and photosensitivity both occur in fewer than 1% of patients. Children and adolescents are particularly sensitive to the early and late extrapyramidal side effects of haloperidol. It is not recommended to treat pediatric patients.
This article uses material from the Wikipedia article Haloperidol, which is released under the Creative Commons Attribution-Share-Alike License 3.0.