Known brand names include Haldol.
A first-generation (typical) antipsychotic given as tablets or as an IM injection for rapid control of severe agitation in schizophrenia. It also controls tics in Tourette's disorder. Movement side effects are common, and it can cause dangerous heart rhythms and neuroleptic malignant syndrome.
Exactly how haloperidol works is not clear. It blocks dopamine D2 receptors in the brain, which is thought to be the main way it eases the symptoms of schizophrenia. It also attaches to alpha-1 receptors, though less strongly, and hardly at all to muscarinic or histamine H1 receptors.
Movement problems are common, often within the first few days: stiffness and shaking like Parkinson's disease, a restless urge to move, or prolonged muscle spasms, more so at higher doses. With longer use, it can cause tardive dyskinesia, involuntary movements that may not go away. It can also disturb the heart's rhythm, especially at high doses or if given into a vein, which is not an approved route. It can trigger neuroleptic malignant syndrome, a life-threatening reaction with high fever, rigid muscles, and confusion.
Haloperidol is an antipsychotic used for psychotic disorders such as schizophrenia, illnesses that cause disturbed or unusual thinking and strong or out-of-place emotions. As a pill, it also controls the motor and vocal tics of Tourette's disorder in children and adults, which are movements or sounds a person feels an uncontrollable need to repeat. As a shot into a muscle, it quickly calms a person with schizophrenia who is severely agitated. It helps control these conditions but does not cure them.
The pills are taken by mouth, and the muscle shot is given for fast control, with a switch to pills as soon as practical. In children, the pills are also used for severe explosive or combative behavior, or for hyperactivity with conduct problems, but only after therapy and other non-antipsychotic medicines have failed. The shot has not been studied in controlled trials in children. It is not approved for psychosis linked to dementia in older adults, who face a higher risk of death on antipsychotics.
Movement side effects are the most common: stiffness and tremor like Parkinson's, an inner restlessness, and sudden muscle spasms of the neck, eyes, or tongue, often in the first few days. The label treats a higher risk of death in older adults with dementia as its boxed warning. It also warns about dangerous heart rhythm changes and sudden death, permanent involuntary movements (tardive dyskinesia), neuroleptic malignant syndrome with high fever and rigid muscles, low white blood cell counts, falls, and low blood pressure.
This is the boxed warning, the warning the FDA label prints first.
Increased mortality in elderly patients with dementia-related psychosis. Antipsychotic-treated older adults with dementia had about 1.6 to 1.7 times the risk of death of placebo patients, mostly from cardiovascular causes or infections. Haloperidol is not approved for dementia-related psychosis.