Antipsychotic medications
Antipsychotic medications are drugs primarily used to treat conditions characterized by a disconnection from reality, such as schizophrenia, bipolar disorder, and severe depression. Originating in the 1950s with the introduction of chlorpromazine, these medications have evolved significantly, leading to the development of both typical and atypical antipsychotics. Typical antipsychotics, like haloperidol, work mainly by blocking dopamine receptors in the brain, but they can lead to serious side effects, including movement disorders and lethargy. In contrast, atypical antipsychotics, initiated with clozapine, also target serotonin receptors and generally have a more favorable side effect profile, although they too can cause adverse reactions.
Further advancements have led to the emergence of third-generation antipsychotics, such as aripiprazole, which offer alternatives for patients who do not respond to earlier treatments. The choice of antipsychotic medication is tailored to the individual's specific symptoms, medical history, and personal circumstances. While these medications have greatly improved treatment outcomes for many, they also require careful management due to potential changes in brain structure and function associated with their use. Overall, antipsychotics remain a crucial component of mental health treatment, reflecting ongoing research and development in the field.
Antipsychotic medications
- TYPE OF PSYCHOLOGY: Biological bases of behavior; psychopathology; stress
DEFINITION: Antipsychotics are medications used to treat people who are out of touch with reality. The first antipsychotics were developed in the 1950s, and numerous, more effective types followed.
Introduction
Antipsychotic medications were first used to treat people experiencing a psychotic episode of being out of touch with reality in the 1950s with the development of chlorpromazine (Thorazine). Originally developed for surgical patients, chlorpromazine was used on patients with psychiatric problems because of its calming effects. Its antipsychotic effect went well beyond calming, as it affected the nervous system, especially the anticholinergic, antidopaminergic, and antihistamine receptors. Chlorpromazine became the model for the class of drugs known as phenothiazinesincluding thioridazine, perphenazine, prochlorperazine, and triflupromazinethe early antipsychotics. These and the other early antipsychotics are known as typical antipsychotics or major tranquilizers, including thioxanthenes (thiothixene and chlorprothixene), dibenzoxazepines (loxapine), dihydroindoles (molindone), and diphenylbutylpiperidines (pimozide). At the time that these drugs were developed, people who were deemed psychotic had traditionally been treated with brain surgery (lobotomies), so medications provided a significant advance in treatment modalities.
A second class of typical antipsychotics is the butyrophenones. This category of drugs includes droperidol and haloperidol (Haldol), which was first developed in the late 1950s but not approved for use in the United States until 1988. Haloperidol is routinely used to treat delirium and acute psychotic states. It is also used to treat Tourette syndrome. Because of the effect of these drugs on the central nervous system, antipsychotic agents are also referred to as neuroleptics. These drugs can cause a decrease in delusions, hallucinations, confusion, and agitation in psychiatric patients and may normalize their motor activity. Such medications have been widely used to treat schizophrenia, bipolar disorder, acute mania, and severe depression.
In many patients, however, treatment with first-generation antipsychotics has been stopped because of adverse side effects. One set of common side effects is extrapyramidal reactions, including low blood pressure, impotence, lethargy, and tardive dyskinesiamovement disorders involving involuntary, purposeless movements, typically of the face, legs, or torso. Once symptoms of tardive dyskinesia occur, they are difficult or impossible to reverse, but some lifestyle and mediation changes can help prevent further or worsening symptoms.
Second-Generation Antipsychotics
To avoid the adverse side effects of the typical antipsychotic agents, medications known as second-generation or atypical antipsychotics were developed. The first of these atypical antipsychotics, clozapine (Clozaril) was developed in 1970, though not approved for use until 1989, and used for the treatment of schizophrenia. This medication, a debenzapine derivative, was found to have a potentially deadly side effect, agranulocytosisa decrease in the white blood cells circulating in the bloodstreamand was voluntarily withdrawn from the market. In 1989, after further testing, it was approved for use by the Food and Drug Administration for individuals with treatment-resistant schizophrenia.
Typical antipsychotics work primarily by blocking the neurotransmitter dopamine, histamine, and norepinephrine in the brain. Atypical antipsychotics work similarly by blocking dopamine and serotonin receptors, but they also activate specific neurotransmitter receptors to better balance the brain’s chemicals. Second-generation antipsychotics include risperidone (Risperdal), which is often used to treat bipolar disorder. Each of the atypical antipsychotics also causes side effects, but in general, these drugs are better tolerated than first-generation antipsychotics.
Third-generation antipsychotics may be used in patients with clozapine intolerance or who do not respond to the drug. These drugs work by limiting dopamine levels in the brain by binding primarily to D3 receptors. They include aripiprazole (Abilify), cariprazine (Vraylar), brexpiprazole (Rexulti), and lumateperone (Caplyta).
Use of These Drugs
Typically, when deciding which medication to prescribe, a physician will consider an individual’s symptoms, age, weight, current and past medications, and family history. Research has shown that most antipsychotic drugs alter the brain’s structure. In some cases, these structural changes are a direct result of the treatment, while in other cases, they are side effects of the medication.
The most commonly used first-generation antipsychotic medications in the US in the twenty-first century were haloperidol (Haldol) and perphenazine. The most frequently prescribed second-generation medications were Seroquel (quetiapine), Abilify and Aristada (aripiprazole), and Perseris and Risperdal (risperidone).
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