Pharmacology for Nurses · Psychopharmacologic Drugs
Antipsychotics
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In 30 seconds
Antipsychotics are drug classes used primarily to treat schizophrenia and other psychotic disorders, and they are also used for bipolar disorder (as mood-stabilizing adjuncts), severe agitation, and — in some cases — as adjuncts in treatment-resistant depression. The organizing idea is the Dopamine hypothesis The theory that psychosis involves excess dopamine signaling in brain reward/thought circuits Full entry → of psychosis: hallucinations, delusions, and disorganized thinking are associated with excessive dopamine signaling, particularly in the mesolimbic pathway, while underactive dopamine in other circuits contributes to negative symptoms and cognitive difficulties. All antipsychotics act on dopamine D2 receptors, and their differences — and most of their adverse effects — follow from how strongly, where, and against what else they act.
The drugs are traditionally split into first-generation (typical) antipsychotics (FGAs) such as haloperidol and chlorpromazine, and second-generation (atypical) antipsychotics (SGAs) such as risperidone, olanzapine, quetiapine, and clozapine. FGAs are potent D2 antagonists and produce a distinctive set of movement disorders — Extrapyramidal symptoms (EPS) Movement disorders from dopamine blockade: dystonia, akathisia, parkinsonism Full entry →, Tardive dyskinesia Late, involuntary face/tongue/limb movements that may be irreversible Full entry →, and the life-threatening Neuroleptic malignant syndrome (NMS) A rare, life-threatening reaction: rigidity, fever, autonomic instability, altered mental status Full entry →. SGAs combine D2 antagonism (or, for aripiprazole, partial agonism) with 5-HT2A antagonism Blockade of a serotonin receptor subtype that reduces EPS risk Full entry →, which lowers EPS risk but shifts the burden to metabolic effects: weight gain, dyslipidemia, and hyperglycemia. For the nurse, this class is about balancing efficacy against a long list of monitorable adverse effects, and about building trust and adherence with people who may be experiencing paranoia or anosognosia (not recognizing their own illness).
Why this matters
Psychotic disorders are chronic, disabling conditions, and antipsychotics are the cornerstone of their treatment — often taken for years. That long exposure makes adverse-effect monitoring a permanent nursing responsibility: movement disorders can become irreversible (tardive dyskinesia), the Metabolic syndrome Weight gain, dyslipidemia, and hyperglycemia associated with SGAs Full entry → associated with SGAs raises cardiovascular risk, and neuroleptic malignant syndrome is a true emergency with a significant mortality risk if unrecognized. Antipsychotics also have prominent anticholinergic, sedative, and hypotensive effects, and many prolong the QT interval, which matters in combination with other QT-prolonging drugs. Nurses administer these drugs in inpatient units, clinics, and long-term care; they perform the standardized movement assessments (e.g., AIMS-style rating), track metabolic panels, and are often the first to notice early EPS such as restlessness or muscle stiffness. Person-first, recovery-oriented language is especially important here: the nurse works with a person experiencing psychosis, never defining them by a diagnosis.
The college version
Core Concepts
The dopamine hypothesis and D2 blockade
Psychosis is linked to overactivity of dopamine in the mesolimbic pathway (driving hallucinations and delusions) and underactivity in mesocortical pathways (contributing to negative symptoms such as flat affect and social withdrawal). Antipsychotics block D2 receptors; how completely and how selectively they do so determines both therapeutic effect and adverse effects. Antagonism in the mesolimbic pathway reduces positive symptoms; antagonism in the nigrostriatal pathway (which controls movement) produces EPS; blockade in the tuberoinfundibular pathway raises prolactin (gynecomastia, galactorrhea, menstrual changes); and blockade in the mesocortical pathway can worsen negative symptoms. This receptor map lets the nurse predict which adverse effect to expect from which drug, rather than memorizing symptom lists.
First-generation (typical) antipsychotics
FGAs (e.g., haloperidol, fluphenazine, chlorpromazine) are potent D2 antagonists with little 5-HT2A activity. They are effective against positive symptoms and are available in short- and long-acting injectable forms, which helps adherence. Their hallmark adverse effects are the extrapyramidal symptoms: acute dystonia (painful muscle spasms, often of the neck, eyes, or tongue, occurring early), akathisia (a tormenting inner restlessness that people describe as "I can't sit still"), drug-induced parkinsonism (tremor, rigidity, shuffling gait), and — after months to years of exposure — tardive dyskinesia (involuntary, repetitive movements of the face, tongue, and limbs that may be irreversible). FGAs also cause sedation, orthostatic hypotension, anticholinergic effects (especially chlorpromazine), and hyperprolactinemia. Neuroleptic malignant syndrome (NMS) — severe muscle rigidity, high fever, autonomic instability, and altered mental status with elevated creatine kinase — can occur with any antipsychotic and is a medical emergency requiring immediate drug discontinuation and supportive care.
Second-generation (atypical) antipsychotics
SGAs (e.g., risperidone, olanzapine, quetiapine, aripiprazole, clozapine) combine D2 blockade (or partial agonism, in aripiprazole's case) with 5-HT2A antagonism. The serotonin component reduces EPS risk at therapeutic doses, which is why these drugs displaced FGAs as first-line treatment. The trade-off is metabolic syndrome: significant weight gain, dyslipidemia, and impaired glucose tolerance/hyperglycemia, with the highest risk associated with olanzapine and clozapine. Other effects vary by drug — risperidone causes more hyperprolactinemia and EPS at higher doses, quetiapine is sedating and can cause orthostatic hypotension, and most SGAs can prolong the QT interval. Clozapine is uniquely reserved for treatment-resistant schizophrenia because it is the most effective agent but carries a risk of Agranulocytosis A dangerous drop in white blood cells associated with clozapine Full entry → (a dangerous drop in white blood cells), which is why its use is tied to mandatory blood monitoring programs. This is a textbook example of risk–benefit balancing: the most effective drug requires the most surveillance.
Nursing monitoring and safety framework
Antipsychotic care is structured around scheduled monitoring: baseline and periodic metabolic panels (weight, glucose, lipids) for SGAs, movement assessments to detect EPS and tardive dyskinesia early, prolactin-related symptom review, ECG/QT considerations especially with other QT-prolonging drugs or cardiac risk factors, and vital signs given sedation and orthostatic hypotension. The nurse teaches the person and family to report muscle stiffness, restlessness, fever, or unusual movements immediately — early fever plus rigidity is the NMS warning. Adherence is supported through education, simplified regimens, and long-acting injectable formulations where appropriate. NMS, if suspected, is treated as an emergency: stop the antipsychotic, notify the provider, and provide supportive care. All monitoring schedules, laboratory orders, and drug choices follow current guidelines and prescriber orders — verify against the current formulary and references.
Common Confusions
| Do Not Confuse | With | Difference |
|---|---|---|
| EPS (dystonia, akathisia, parkinsonism) | Tardive dyskinesia | EPS are early, usually reversible movement effects of dopamine blockade; tardive dyskinesia is late and may be irreversible — treat them very differently |
| Akathisia | Anxiety or agitation | Akathisia is a drug-induced inner restlessness with compulsive pacing — mislabeling it as anxiety leads to wrong treatment and continued distress |
| NMS | Serotonin syndrome | Both are hyperthermic emergencies, but NMS comes from dopamine blockade (antipsychotics) with rigidity and elevated CK; serotonin syndrome comes from serotonin excess (serotonergic drugs) with hyperreflexia |
| First-generation (typical) | Second-generation (atypical) | FGAs: potent D2, more EPS; SGAs: D2 + 5-HT2A, fewer EPS but more metabolic effects — the adverse-effect trade-off flips |
| Antipsychotic | Antidepressant | Antipsychotics target dopamine/psychosis; antidepressants target monoamine reuptake/depression — though some atypical antipsychotics are used as adjuncts in depression |
| Positive symptoms | Negative symptoms | Positive (hallucinations, delusions) respond well to D2 blockade; negative (flat affect, withdrawal) respond poorly and may even worsen with strong blockade |
Eli explains
The same idea, in plain words
Explain it like I’m 10
The brain has a "gas pedal" chemical called dopamine that can get stuck in the "on" position, making a person hear or see things that aren't there and believe things that aren't real. Antipsychotic medicines are like a brake on that pedal — they slow the false signals down. But pressing the brake too hard can also stiffen the body's muscles or make a person feel restless, and some of these medicines can change appetite and weight, so nurses watch closely for those effects while the medicine does its job.
Worked example
Catching early EPS before it becomes a crisis. On day 3 of a new FGA, a nursing student is helping a person with schizophrenia with morning care. The person, who usually sits quietly, keeps pacing, crossing and uncrossing their legs, and says, "I can't sit still — my legs are crawling." The student recognizes akathisia — not anxiety, not "acting out" — and also notices the person's neck is slightly turned and stiff. The student reports both observations promptly; the provider adjusts the plan (for example, an anticholinergic agent or a change in antipsychotic selection per orders), and the symptoms settle. Later, the student reviews the monitoring schedule with the instructor: metabolic labs for the SGA the person will likely transition to, a baseline movement assessment to compare against future exams, and teaching for the person and family about reporting fever with muscle rigidity — the NMS warning — immediately. The scenario illustrates the nurse's core role: observing precisely, knowing what the observation means mechanistically, and acting within scope by reporting and documenting.
Key takeaways
- Dopamine hypothesis: psychosis is linked to excess dopamine signaling; antipsychotics act at D2 receptors — location of blockade predicts effect (mesolimbic = efficacy; nigrostriatal = EPS; tuberoinfundibular = hyperprolactinemia).
- FGAs (e.g., haloperidol): potent D2 antagonists; hallmark adverse effects are EPS (dystonia, akathisia, parkinsonism) and late, potentially irreversible tardive dyskinesia.
- SGAs (e.g., risperidone, olanzapine, quetiapine): D2 + 5-HT2A; fewer EPS but metabolic syndrome (weight gain, dyslipidemia, hyperglycemia) — monitor glucose and lipids.
- NMS is an emergency: rigidity + high fever + autonomic instability + altered mental status (+ elevated CK). Stop the drug, notify the provider, support vital functions.
- Clozapine is reserved for treatment-resistant illness because of agranulocytosis risk; its use is tied to mandatory blood monitoring.
- Aripiprazole is a D2 partial agonist — it dampens excess dopamine without fully blocking the receptor.
- Baseline and periodic monitoring (weight, glucose, lipids, movement exams, vital signs) is a core nursing function; QT prolongation matters with other QT drugs.
- Recovery-oriented, person-first language: a person experiencing psychosis, not "a schizophrenic."
Check yourself
5 review questions from the chapter. Try each one, then open the answer.
Why do SGAs cause less EPS than FGAs, and what adverse-effect burden replaces it?
Show answer
SGAs combine D2 blockade with 5-HT2A antagonism (or partial agonism), which reduces extrapyramidal effects at therapeutic doses. The trade-off is a higher burden of metabolic effects — weight gain, dyslipidemia, and hyperglycemia — requiring scheduled monitoring.
A person on an antipsychotic develops severe muscle rigidity, a high fever, and confusion. What is the priority action and why?
Show answer
Suspect neuroleptic malignant syndrome, a life-threatening emergency. Stop the antipsychotic immediately, notify the provider, and provide supportive care (cooling, fluids, monitoring) while the cause is confirmed and treated.
What is tardive dyskinesia, and how does scheduled nursing assessment help?
Show answer
Tardive dyskinesia is a late, potentially irreversible syndrome of involuntary face, tongue, and limb movements from long-term dopamine blockade. Routine standardized movement assessments catch it early, when dose adjustment or drug change can still make a difference.
Why is clozapine reserved for treatment-resistant schizophrenia despite being highly effective?
Show answer
Clozapine is the most effective antipsychotic for refractory schizophrenia, but it can cause agranulocytosis — a potentially fatal drop in white blood cells — so it is reserved for people who have not responded to other agents and is managed with mandatory blood monitoring.
Where in the brain does dopamine blockade produce therapeutic benefit, EPS, and hyperprolactinemia — and what does that receptor map predict?
Show answer
Mesolimbic blockade → reduced positive symptoms (benefit); nigrostriatal blockade → EPS; tuberoinfundibular blockade → hyperprolactinemia. The map predicts that a potent, nonselective D2 antagonist (typical FGA) will be effective but movement- and prolactin-heavy, guiding monitoring priorities.
Study tools & related lessonsKey vocabulary · Related
Key vocabulary
- Dopamine hypothesis
- The theory that psychosis involves excess dopamine signaling in brain reward/thought circuits
- D2 receptor
- The dopamine receptor subtype antipsychotics block
- Extrapyramidal symptoms (EPS)
- Movement disorders from dopamine blockade: dystonia, akathisia, parkinsonism
- Tardive dyskinesia
- Late, involuntary face/tongue/limb movements that may be irreversible
- Neuroleptic malignant syndrome (NMS)
- A rare, life-threatening reaction: rigidity, fever, autonomic instability, altered mental status
- 5-HT2A antagonism
- Blockade of a serotonin receptor subtype that reduces EPS risk
- Metabolic syndrome
- Weight gain, dyslipidemia, and hyperglycemia associated with SGAs
- Agranulocytosis
- A dangerous drop in white blood cells associated with clozapine
Sources & references
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