chapter 31
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Chapter 31. Antipsychotic Agents and Their Use in Schizophrenia. Antipsychotic Agents. Chemically diverse group of compounds Used for diverse spectrum of psychotic disorders Schizophrenia, delusional disorders, bipolar disorders, depressive psychoses, drug-induced psychoses - PowerPoint PPT PresentationTRANSCRIPT
Copyright © 2013, 2010 by Saunders, an imprint of Elsevier Inc.
Chapter 31
Antipsychotic Agents and Their Use in Schizophrenia
2Copyright © 2013, 2010 by Saunders, an imprint of Elsevier Inc.
Antipsychotic Agents Chemically diverse group of compounds Used for diverse spectrum of psychotic
disorders Schizophrenia, delusional disorders, bipolar
disorders, depressive psychoses, drug-induced psychoses
Also used to suppress emesis and to treat Tourette’s syndrome and Huntington’s chorea
Should not be used to treat dementia in the older adult
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Antipsychotic Agents First-generation antipsychotics (FGAs) or
conventional antipsychotics Block receptors for dopamine in CNS Cause serious movement disorders
(extrapyramidal symptoms [EPS]) Second-generation antipsychotics (SGAs) or
atypical antipsychotics Produce only moderate blockade of dopamine
receptors; stronger blockade for serotonin Fewer EPS
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Antipsychotic Agents Top-selling medications in the United States
in 2009 Total sales of $14.6 billion FGA higher risk of EPS SGA higher risk of metabolic effects
(diabetes, dyslipidemia)
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Clinical Presentation Disordered thinking and reduced ability to
comprehend reality Three types of symptoms
Positive symptoms and negative symptoms Cognitive symptoms
Acute episodes Residual symptoms Long-term course Causes
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Conventional Antipsychotic Agents I: Group Properties
Classification Mechanism of action Therapeutic uses Adverse effects Physical and psychologic dependence Drug interactions Toxicity
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Classification Classification by potency
Low potency: chlorpromazine HCl (Thorazine) Medium potency: loxapine (Loxitane) High potency: haloperidol (Haldol)
Chemical classification Six major chemical categories Drugs in all groups equivalent with respect to
antipsychotic actions
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Mechanism of Action Conventional antipsychotic drugs block a
variety of receptors within and outside the CNS
They block dopamine2 (D2) receptors in the mesolimbic area of the brain
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Therapeutic Uses Schizophrenia Bipolar disorder (manic-depressive illness) Tourette’s syndrome Prevention of emesis Other applications
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Adverse Effects Extrapyramidal symptoms (EPS) Acute dystonia Parkinsonism Akathisia Tardive dyskinesia
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Adverse Effects Other adverse effects
Neuroleptic malignant syndrome• Rare but serious reaction• Risk of death without treatment• Sweating, rigidity, sudden high fever, autonomic
instability Anticholinergic effects
• See Table 31-3. Orthostatic hypotension
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Adverse Effects Other adverse effects (cont’d)
Sedation Neuroendocrine effects Seizures Sexual dysfunction Dermatologic effects Agranulocytosis Severe dysrhythmias
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Physical and Psychologic Dependence
Development of physical and psychologic dependence is rare
Abrupt withdrawal of antipsychotics can precipitate a mild abstinence syndrome
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Drug Interactions Anticholinergic drugs
Intensify the anticholinergic effect CNS depressants
Can intensify the depressant effect Levodopa and direct dopamine receptor
agonists May counteract the antipsychotic effects of
neuroleptics
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Toxicity Conventional antipsychotic drugs are very
safe Death by overdose is extremely rare Overdose produces hypertension, CNS
depression, and EPS Treatment
Intravenous fluids, alpha-adrenergic agonist, gastric lavage
Emetics not effective: neuroleptics block the antiemetic action
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Conventional Antipsychotic Agents II: Individual Agents
Low-potency agents Medium-potency agents High-potency agents Depot preparations
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Low-Potency Agents Chlorpromazine (Thorazine)
Therapeutic uses Pharmacokinetics Adverse effects Drug interactions Preparations, dosage, and administration
• Oral therapy• Parenteral therapy
Thioridazine (Mellaril)
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Medium-Potency Agents Loxapine (Loxitane) Molindone (Moban) Perphenazine (Trilafon)
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High-Potency Agents Haloperidol (Haldol)
Actions and uses Pharmacokinetics Adverse effects Preparations, dosage, and administration
• Oral therapy • Intramuscular therapy
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Other High-Potency Agents Fluphenazine (Prolixin) Trifluoperazine (Stelazine) Thiothixene (Navane) Pimozide (Orap)
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Atypical Antipsychotic Agents Introduced in the 1990s Less risk of EPS than FGAs Increased risk of weight gain, diabetes, and
dyslipidemia Examples: clozapine and other atypical
antipsychotics
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Clozapine Mechanism of action
Blocks dopamine and serotonin Therapeutic use
Schizophrenia Levodopa-induced psychosis
Pharmacokinetics
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Clozapine Adverse effects and interactions
Agranulocytosis Seizures Diabetes Weight gain Myocarditis Effects in older adult patients with dementia
• About double the mortality rate Drug interactions
Preparations, dosage, and administration
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Other Atypical Antipsychotics Risperidone (Risperdal)
Mechanism of action• Binds to multiple receptors
Pharmacokinetics Therapeutic effects Adverse effects
• Generally infrequent and mild Preparations, dosage, and administration
• Schizophrenia, oral therapy• Schizophrenia, intramuscular therapy• Bipolar disorder
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Other Atypical Antipsychotics
Olanzapine (Zyprexa) Mechanism of action
• Blocks 5-HT2 receptors• Blocks D2 receptors
Pharmacokinetics Therapeutic uses
• Schizophrenia• Bipolar disorder
Adverse effects
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Other Atypical Antipsychotics
Olanzapine (Zyprexa) (cont’d) Preparations, dosage, and administration
• Schizophrenia dosage Oral dosage
• Bipolar disorder dosage Oral formulation
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Other Atypical Antipsychotics
Quetiapine (Seroquel) Actions and uses Pharmacokinetics Adverse effects Drug interactions Preparations, dosage, and administration
• Schizophrenia dosage• Bipolar disorder dosage
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Other Atypical Antipsychotics
Ziprasidone (Geodon) Mechanism of action
• Blocks multiple receptors: D2, 5-HT2, H1
Pharmacokinetics Adverse effects Drug interactions Preparations, dosage, and administration
• Schizophrenia, intramuscular dosage• Bipolar disorder (see Table 31-4)
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Other Atypical Antipsychotics
Aripiprazole (Abilify) Contrasts with other atypical antipsychotic agents Mechanism of action
• Blocks multiple receptor types Pharmacokinetics Adverse effects Drug interactions Preparations, dosage, and administration
• Schizophrenia dosage• Bipolar disorder dosage
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Depot Preparations Depot antipsychotics: long-acting, injectable
formulations used for long-term maintenance therapy of schizophrenia
No evidence that depot preparations pose an increased risk of side effects
Three depot preparations available Haloperidol decanoate (Haldol Decanoate) Fluphenazine decanoate (Prolixin Decanoate) Risperidone microspheres (Risperdal Consta)
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Schizophrenia Drug Therapy Three major objectives
Suppression of acute episodes Prevention of acute exacerbations Maintenance of the highest possible level of
functioning Drug selection Dosing Route
Oral (tablets, capsules, liquids) Intramuscular
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Schizophrenia Drug Therapy Most FGAs and SGAs are equally effective,
except for clozapine, which is more effective than the rest FGAs: significant risk of EPS SGAs: risk of metabolic effects FGAs: cost 10 times less than SGAs
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Schizophrenia Drug Therapy Dosing
Highly individualized Older adult patients require relatively small doses. Size and timing likely to be changed over course
of therapy Routes
Oral (preferred) Intramuscular
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Schizophrenia Drug Therapy Initial therapy Maintenance therapy Adjunctive drugs
Benzodiazepines Antidepressants
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Schizophrenia Drug Therapy Promoting adherence
Ensure that the medication is taken Encourage family members to oversee medication
for outpatients Provide patients with instructions Inform patients and their families that
antipsychotics must be taken on a regular schedule
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Schizophrenia Drug Therapy Promoting adherence (cont’d)
Inform patients about side effects of treatment Assure patients that antipsychotic drug use does
not lead to addiction Establish a good therapeutic relationship with
patient Use an intramuscular depot preparation for long-
term therapy
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Schizophrenia Nondrug Therapy Counseling for patient and family Behavioral therapy Vocational training