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Chapter 18 - antipsychotic drugs
Chapter 18 notes
Terms in this set (57)
Antipsychotic drugs are generally conceptualized in two or three ways
The two categories are (1) traditional (typical) antipsychotics, or first-generation drugs and (2) atypical antipsychotics, or second-generation drugs.
Traditional antipsychotic drugs, developed between 1950 and 1990, are further divided based on ?
low-potency drugs tend to cause more intense __________ effects and also _________ effects.
high-potency drugs cause more ________ side effects.
What are the three high potency traditional antipsychotic drugs?
What are the three moderate potency traditional antipsychotic drugs?
What are the three low potency traditional antipsychotic drugs?
That is, drugs developed between 1950 and 1990 are considered as traditional or typical antipsychotics. The newer agents (from 1990 on) are referred to as atypical because of the following characteristics:
1.Reduced or no risk for EPSEs
2.Increased effectiveness in treating negative symptoms
3.Minimal risk of tardive dyskinesia (TD)
4.Reduced or no risk for elevated prolactin
Four dopaminergic tracts are important for understanding the actions of antipsychotic drugs. What are they?
1. Nigrostriatal system 2. Tuberoinfundibular system 3. Mesolimbic system 4. Mesocortical system
the student must recognize the existence of dopamine-dependent areas of the brain that communicate with dopamine-synthesizing areas (substantia nigra and ventral tegmental areas in the midbrain) via different neuronal tracts.
Tract 1: The nigrostriatal tract is involved in movement. Traditional antipsychotic blockade can cause EPSEs.
Tract 2: The tuberoinfundibular tract modulates pituitary function. Traditional antipsychotic blockade can lead to elevation in prolactin levels.
Tract 3: The mesolimbic tract is involved in emotional and sensory processes. Traditional antipsychotic blockade normalizes these processes in individuals with schizophrenia, relieving or eliminating hallucinations and delusions.
Tract 4: The mesocortical tract is involved in cognitive processes. Traditional antipsychotic blockade can intensify negative and cognitive problems.
Antipsychotic drugs are used primarily to treat psychotic disorders—specifically?
schizophrenia, bipolar disorder, and other chronic mental illness.
Positive Symptoms: Caused by Excessive Dopamine in Mesolimbic Tract are?
Feelings of persecution
Negative Symptoms: Caused by Too Little Dopamine in Mesocortical Tract are?
Difficulty with abstractions
Passive social withdrawal
Poor grooming and hygiene
Poverty of speech
A tranquilizing effect occurs within an hour or so after ingestion. Antipsychotic effects are often observed within a few weeks, with improvement continuing for up to ________.
6 to 8 weeks or longer
Antipsychotic drugs are most effective in treating what we call the __________ symptoms of schizophrenia. These symptoms include hallucinations and delusions.
____________ symptoms develop over an extended period and include flattened affect, verbal paucity, and a lack of drive or goal-directed activity
As a rule, the more bizarre the behavior of a person experiencing psychotic symptoms (more positive symptoms), the more likely that an antipsychotic drug will be __________.
Individuals with schizophrenia are often __________ because of their internal turmoil and, perhaps, their neurochemical state. Antipsychotic drugs slow psychomotor activity.
What are affective symptoms sometimes associated with schizophrenia and often respond to antipsychotic drugs.
Affective flattening, blunting, inappropriateness, and lability
What is a cardinal symptom of negative schizophrenia and might sometimes associated with schizophrenia and often respond to antipsychotic drugs. However, a flat affect is a cardinal symptom of negative schizophrenia and might respond only to an atypical antipsychotic drug.
Oral drugs are absorbed in 1 to 6 hours, whereas the newer disintegrating tablets are absorbed within _________. These highly lipid-soluble drugs accumulate in fatty tissue and are released slowly.
Antipsychotics are highly bound to plasma proteins. Physiologic changes that even slightly disrupt this level of protein-binding action might do what and potentially have a greater effect?
increase the percentage of free drug
Antipsychotics are metabolized in the liver by the cytochrome P-450 enzyme system. Their average half-life ranges from ?
10 to 30 hours.
What is thought to be the single most important cause of symptom exacerbation and rehospitalization.
When a patient does not respond to antipsychotic drug therapy, the nurse's assessment of the patient might be quite helpful to the prescriber. Two considerations should be kept in mind when assessing a patient's response:
1.Is the patient actually taking the drug?
2.Has the drug been given a fair trial (usually 3 to 6 weeks)?
What are the anticholinergic side effects?
Signs and symptoms: Constipation, decreased sweating, dilated pupils, dry mouth, slowed bowels and bladder.
What are the EPSE side effects?
Signs and symptoms: Akathisia, akinesia, dystonia, parkinsonism, tardive dyskinesia
What are the signs and symptoms of neuroleptic malignant syndrome (NMS)?
high fever and rigidity
Nursing Alert: Anticholinergic Effects
1.Can increase intraocular pressure, aggravating narrow-angle glaucoma
2.Can intensify prostatic hypertrophy, making urination even more difficult
3.Can trigger arrhythmias and cause death
What is the major antiadrenergic effect of antipsychotic drugs. The blocking of alpha-1 receptors is the primary cause.
Definition of Akathisia?
Akathisia is a subjective feeling of restlessness demonstrated by restless legs, jittery feelings, and nervous energy. Akathisia is the most common EPSE and responds poorly to treatment. It is a major reason why patients stop taking medications
The following formula traces the most familiar path leading to rehospitalization:
EPSEs → nonadherence → relapse → rehospitalization
Definition of Akinesia?
Akinesia refers to an absence of movement; however, slowed movement, or bradykinesia, is more likely. Symptoms include weakness, fatigue, painful muscles, and anergia. Akinesia responds to anticholinergics.
Definition of Distonia?
Dystonias are abnormal postures caused by involuntary muscle spasms
Types of dystonias include the following:
•Torticollis—contracted positioning of the neck
•Oculogyric crisis—contracted positioning of the eyes upward
•Laryngeal-pharyngeal constriction (potentially life-threatening)
What is Tardive Dyskinesia?
Tardive means "late appearing." Tardive dyskinesia (TD) is an EPSE that tends to develop after approximately 6 months or more of antipsychotic therapy. In fact, anticholinergics typically worsen the symptoms of TD
What is the best approach to dealing with tardive dyskinesia?
Prevention is by far the best approach to dealing with TD.
What drugs are used to treat NMS?
Dantrolene (Dantrium), a skeletal muscle relaxant, and bromocriptine (Parlodel), a dopamine agonist, are drugs of choice for treating NMS
Antipsychotics should not be reinstituted for at least how long after complete resolution of NMS symptoms.
What presents as a reduced metabolism of glucose and resistance to insulin by insulin receptors on cells. This can result in type 2 diabetes with the associated problems of hyperglycemia, obesity, elevated lipid levels, coagulation abnormalities, and hypertension
Metabolic syndrome (or insulin resistance syndrome)
Three or more of the following constitute metabolic syndrome
1.Abdominal girth over 40 inches in men and 35 inches in women
2.Elevated triglycerides (at or above 150 mg/dL)
3.Reduced high-density lipoproteins at or below 40 mg/dL in men or 50 mg/dL in women
4.Elevated blood pressure or treatment for same
5.Elevated fasting glucose at or above 100 mg/dL
The atypical antipsychotics most likely to cause metabolic syndrome appear to be ?
clozapine and olanzapine
What causes agranulocytosis in 1% of patients and is potentially fatal.
What are indicators of an antipsychotic overdose?
An overdose can cause severe CNS depression, hypotension, and EPSEs. Restlessness or agitation, convulsions, hyperthermia, increased anticholinergic symptoms, and arrhythmias are other indicators of an overdose
Chlorpromazine is a low-potency agent and thus results in anticholinergic and antiadrenergic effects. It is also sedating and causes significant weight gain. EPSEs are moderately produced.
Thioridazine has been therapeutic in children with severe behavioral problems marked by combativeness. This drug has a maximum upper limit of 800 mg/day because of the possibility of pigmentary retinopathy, which decreases visual acuity, impairs night vision, and is characterized by pigment deposits on the fundus.
Fluphenazine decanoate (prolixin decanoate), the long-acting form, is beneficial for patients who do not comply with a daily oral medication regimen. This injection can be given every 2 to 3 weeks
cause more EPSEs and fewer anticholinergic side effects than low-potency drugs. It is used extensively in older adults (because of fewer anticholinergic effects) and in pediatric psychiatry.
Clozapine has been referred to as the gold standard in the management of schizophrenia. clozapine causes significant anticholinergic effects, orthostasis, sedation, and weight gain. Sexual dysfunction also occurs and, with weight gain, is particularly troublesome and has social implications.
Clozapine is primarily metabolized by P-450 1A2. This is important, because most patients with schizophrenia smoke, and cigarette smoking induces 1A2, causing a __________ level of clozapine
Agranulocytosis is clinically defined as an absolute neutrophil count (ANC) below __________ and might be caused by __________.
500/mm3, bone marrow suppression.
risperidone theoretically has a favorable receptor profile for both positive and negative schizophrenia. Nonetheless, risperidone significantly blocks alpha-1 and H1 receptors, resulting in orthostatic hypotension, sedation, and appetite stimulation, respectively. At higher doses, patients taking risperidone have experienced EPSEs and hyperprolactinemia. Other side effects include insomnia (in some patients), agitation, headache, anxiety, and rhinitis
has a high affinity for cholinergic, H1, and alpha-1 receptors, resulting in anticholinergic effects, sedation, weight gain, and orthostasis. Olanzapine causes considerable weight gain in some patients. Olanzapine has proven effective in treating acute mania and is an FDA-approved drug for monotherapy for bipolar disorder
However, quetiapine antagonizes alpha-1 receptors, which leads to orthostatic hypotension, and antagonizes H1 receptors, which leads to sedation and appetite stimulation. Clinically, quetiapine is effective for both positive and negative symptoms, provokes few EPSEs, does not significantly increase serum prolactin levels, and appears to improve elements of cognitive function
Ziprasidone is effective for both positive and negative schizophrenia. Common side effects include nausea, dyspepsia, abdominal pain, constipation, somnolence, insomnia, and coryzal symptoms. Ziprasidone appears to cause less weight gain than some other atypical agents. Ziprasidone has been linked to potential cardiac problems related to lengthening of the QTc interval.
It is referred to as a dopamine system stabilizer (DSS) and represents what has been called the third generation of antipsychotics. DSSs are thought to balance the dopamine systems by increasing dopamine in brain areas in which dopamine is deficient and decreasing dopamine in brain areas in which dopamine is overactive
It is available only as a sublingual tablet, so it is ineffective if swallowed. It is approved for the treatment of both acute schizophrenia and bipolar disorder.