What Are They, How They Work, and More
Author: Corinne Tarantino, MPH
Editors: Ahaana Singh, Nimmit Vyas, PharmD
Illustrator: Abbey Richard
Copyeditor: Joy Mapes
What are neuroleptics?
Neuroleptics, also known as antipsychotic medications, are medications that block dopamine receptors in the nervous system. They are mainly prescribed to manage mental illnesses, such as schizophrenia and bipolar disorder, as well as psychosis. Psychosis describes loss of touch with reality, with specific symptoms such as difficulty concentrating, hallucinating, and engaging in movements without a purpose (i.e., psychomotor activity).There are two classes of neuroleptic drugs: the “typical,” also known as “first-generation,” drugs and the more commonly prescribed “atypical”, or “second-generation,” drugs. First-generation neuroleptics are further categorized as high or low potency, based on the amount of the drug required to minimize the symptoms. Common high-potency, first-generation neuroleptics include haloperidol, trifluoperazine, and fluphenazine. Common low-potency, first-generation neuroleptics include thioridazine, chlorpromazine, and thiothixene. Among second-generation medications, clozapine, olanzapine, paliperidone, and risperidone are the most frequently prescribed.
How do neuroleptics work?
Neuroleptics typically work by affecting dopamine and, sometimes, serotonin levels in the brain to decrease psychosis symptoms. Dopamine and serotonin are both neurotransmitters, small molecules that transmit information across nerve cells and affect many major body systems, like the cardiovascular and nervous systems. Dopamine can affect four pathways in the brain: the mesolimbic, mesocortical, nigrostriatal, and tuberoinfundibular pathways. Due to its effect on these pathways, dopamine plays an important role in significant body functions, including motor control, motivation, arousal, reinforcement, and reward. Meanwhile, serotonin is known for its roles in the regulation of mood, body temperature, and appetite, among other body functions. Maintaining a balance of neurotransmitters is critical for proper execution and regulation of body functions. In cases of imbalance, neuroleptics work to regulate the associated functions.
Neuroleptics block dopamine receptors in the brain, so they are prescribed when symptoms are associated with an excess of dopamine in the body. Most neuroleptics affect dopamine D2 receptors in the mesolimbic pathway of the brain, decreasing the positive, or present, symptoms of psychosis, such as hallucination, delusion, and disorganized thought. However, first-generation neuroleptics also block the dopamine receptors on other pathways, such as the mesocortical pathway. These additional blocks have been associated with potentially worsening negative symptoms, or symptoms that take away typical functions. Examples of negative symptoms include lack of emotionality, social withdrawal, and lack of motivation. In contrast, second-generation neuroleptics block both D2 receptors and serotonin 5-HT2A receptors in the mesocortical pathway of the brain, which reduces negative symptoms.
What are neuroleptics used for?
In general, neuroleptics are most commonly prescribed for reducing psychosis symptoms associated with schizophrenia. Schizophrenia is defined by the American Psychiatric Association as a serious mental disorder characterized by a variety of positive, negative, and disorganized symptoms, which can affect many aspects of daily functioning, including mood, thoughts, and feelings. Schizophrenia typically begins in early adulthood and often presents with incoherent or illogical thought, disordered speech, impaired emotional expression, and hallucinations. Since schizophrenia is commonly believed to result from increased dopamine levels, neuroleptics may effectively treat the disorder.Neuroleptics may also be prescribed to treat psychosis symptoms associated with other mental health conditions, such as acute mania, bipolar disorder, anxiety, depression, and obsessive compulsive disorder. In some cases, second-generation neuroleptics may be prescribed for Tourette syndrome, a disorder of uncontrollable, repetitive movements that starts in childhood.
What are the side effects of neuroleptics?
High-potency, first-generation neuroleptics, such as haloperidol and fluphenazine, are likely to produce extrapyramidal symptoms, which are movement disorders caused by medications. Examples of extrapyramidal symptoms include muscle spasms (i.e., acute dystonia), motor restlessness (i.e., akathisia), and parkinsonism, which is characterized by instability, shuffling gait, and muscle rigidity. Tardive dyskinesia is another extrapyramidal effect, characterized by involuntary, repetitive movement, such as smacking lips or waving arms. Tardive dyskinesia may occur after long-term use of the medication and can be irreversible. Neuroleptic malignant syndrome is a rare, potentially fatal extrapyramidal side effect, presenting with symptoms such as confusion, muscle rigidity, seizures, coma, agitation, and hyperthermia and requiring immediate medical attention. Additional potential side effects of high-potency, first-generation neuroleptics include an increased time between heart beats and metabolic symptoms, such as weight gain and high cholesterol.
Low-potency, first-generation neuroleptics, such as chlorpromazine and thioridazine, will commonly result in side effects similar to those seen with anticholinergics, which are medications that block the neurotransmitter acetylcholine. These side effects may include dry mouth, sedation, constipation, and dizziness. In general, low-potency, first-generation neuroleptics are less likely to cause extrapyramidal symptoms.neuroleptics may not be recommended for people with heart disease, liver damage, Parkinson’s disease, low levels of white blood cells, or severe depression. Consultation with a healthcare professional is advised when deciding whether neuroleptics are a viable treatment option.
What are the most important facts to know about neuroleptics?
Neuroleptics, also called antipsychotics, are medications that block dopamine, and sometimes, serotonin receptors in the brain to reduce symptoms of psychosis, particularly in cases of schizophrenia. There are two classes of neuroleptic medications: first-generation and second-generation neuroleptics. First-generation neuroleptics block only dopamine receptors and subsequently decrease positive symptoms, while second-generation neuroleptics block serotonin receptors in addition to dopamine receptors, decreasing both positive and negative symptoms. Neuroleptics may be prescribed to manage symptoms of many mental health conditions, including schizophrenia and bipolar disorder. Second-generation neuroleptics may also be prescribed to reduce symptoms of Tourette syndrome. First-generation neuroleptics are associated with a variety of side effects, including extrapyramidal symptoms from high-potency drugs and anticholinergic symptoms from low-potency drugs. Since second-generation neuroleptics generally cause fewer side effects, they are more frequently prescribed.
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Resources for research and reference
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