Antipsychotic drugs are used to treat drug-induced psychosis, schizophrenia, extreme mania, depression that is resistant to other therapy, and other CNS conditions. Antipsychotics are sometimes referred to as tranquilizers because they produce a state of tranquility. Selection of antipsychotic medication is based on the patient’s ability to tolerate the adverse effects. First-generation antipsychotics, also called “typical” antipsychotics, have similar mechanisms of action and several potential adverse effects. An example of a first generation antipsychotic is haloperidol. Second-generation antipsychotics, also referred to as “atypical” antipsychotics, have fewer adverse effects. An example of an atypical antipsychotic is risperidone.[1] Both conventional and atypical antipsychotics have a Boxed Warning indicating that elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death.
Mechanism of Action: All antipsychotics block dopamine receptors in the brain. However, the precise mechanism of action has not been clearly established. First-generation antipsychotics, such as haloperidol, block dopamine receptors in certain areas of the CNS, such as the limbic system and the basal ganglia. These areas are associated with emotions, cognitive function, and motor function, so dopamine blockage thus produces a tranquilizing effect in psychotic patients. However, several adverse effects are also caused by this dopamine blockade.
Second-generation, or atypical, antipsychotics block specific dopamine 2 receptors and specific serotonin 2 receptors, thus causing fewer adverse effects.
Indications: Haloperidol is primarily indicated for schizophrenia and Tourette’s disorder. Risperidone is primarily indicated for schizophrenia but is also used for acute manic episodes and for irritability caused by autism. Some atypical antipsychotics are also used as adjunct therapy for depression.
Nursing Considerations: Elderly patients with dementia-related psychosis treated with antipsychotic drugs should be closely monitored for signs and symptoms of cardiovascular events or infections such as pneumonia.
Haloperidol is contraindicated in patients with Parkinson’s disease or dementia with Lewy body.
Patients who are concurrently taking lithium and antipsychotics should be monitored closely for neurotoxicity (weakness, lethargy, fever, tremulousness, confusion, and extrapyramidal symptoms), and symptoms should be immediately reported.
Side Effects/Adverse Effects: Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death due to cardiovascular or infection-related causes.
First-generation antipsychotic medications have several potential serious adverse effects such as tardive dyskinesia, neuroleptic malignant syndrome (NMS), and extrapyramidal symptoms. These adverse effects are due to the blockage of alpha-adrenergic, dopamine, endocrine, histamine, and muscarinic receptors. For additional details about these types of receptors, see the “Autonomic Nervous System” chapter. Table 8.9a describes adverse effects associated with first-generation antipsychotics. Patients should be warned to not consume alcohol and that their ability to operate machinery or drive may be impaired.
Table 8.9a Potential Adverse Effects of Antipsychotic Medication[2]
| Adverse Effect | Definition |
|---|---|
| Tardive Dyskinesia | Involuntary contraction of the oral and facial muscles (such as tongue thrusting) and wavelike movements of the extremities. |
| Neuroleptic Malignant Syndrome (NMS) | Potentially life-threatening adverse effect that includes high fever, unstable blood pressure, and myoglobinemia. |
| Extrapyramidal Symptoms | Involuntary motor symptoms similar to those associated with Parkinson’s disease. Includes symptoms such as akathisia (distressing motor restlessness) and acute dystonia (painful muscle spasms.) Often treated with anticholinergic medications such as benztropine and trihexyphenidyl. |
Second-generation, or atypical, antipsychotics are less likely to cause adverse effects, but have a potential to do so. Atypical antipsychotics may also cause metabolic changes such as hyperglycemia, hyperlipidemia, and weight gain.
Patient Teaching & Education: Advise patients to take medication as directed. Medication doses should be evenly spaced throughout the day. This drug may require several weeks to obtain desired effects. Patients should be advised regarding the possibility of extrapyramidal symptoms and that abrupt withdrawal may cause dizziness; nausea and vomiting; and/or uncontrolled movements of mouth, tongue, or jaw. Additionally, the patient should be careful to avoid alcohol or other CNS depressants while using the medication.
Now let’s take a closer look at the medication grid for haloperidol and risperidone in Table 8.9b.[3],[4]
Table 8.9b Haloperidol and Risperidone Medication Grid
| Class/Subclass | Prototype/Generic | Administration Considerations | Therapeutic Effects | Adverse/Side Effects |
|---|---|---|---|---|
| 1st-Generation Antipsychotic
2nd-Generation (atypical) Antipsychotic |
haloperidol | Boxed Warning: Monitor elderly patients with dementia closely for symptoms of cardiovascular events or infection
Advise patients to avoid alcohol, operate machinery, or drive |
Decrease symptoms of psychosis, hallucinations, delusions, and delirium | Life-threatening cardiovascular events or infections
Tardive dyskinesia Neuroleptic malignant syndrome Extrapyramidal symptoms Hypersensitivity reactions Falls related to sedation, motor instability, and postural hypotension |
- McCuistion, L., Vuljoin-DiMaggio, K., Winton, M., & Yeager, J. (2018). Pharmacology: A patient-centered nursing process approach. pp. 227-305. Elsevier. ↵
- McCuistion, L., Vuljoin-DiMaggio, K., Winton, M., & Yeager, J. (2018). Pharmacology: A patient-centered nursing process approach. pp. 227-305. Elsevier. ↵
- This work is a derivative of DailyMed by U.S. National Library of Medicine in the Public Domain. ↵
- McCuistion, L., Vuljoin-DiMaggio, K., Winton, M., & Yeager, J. (2018). Pharmacology: A patient-centered nursing process approach. pp. 227-305. Elsevier. ↵
Involuntary contraction of the oral and facial muscles (such as tongue thrusting) and wavelike movements of the extremities.
Involuntary motor symptoms similar to those associated with Parkinson’s disease. Includes symptoms such as akathisia (distressing motor restlessness) and acute dystonia (painful muscle spasms.) Often treated with anticholinergic medications such as benztropine and trihexyphenidyl.
Distressing motor restlessness.
Painful muscle spasms.
