Chapter02-Neurobiologic Theories & psychopharmacology.pptx

Chapter 2 Neurobiologic Theories and Psychopharmacology Dr. Corina Alfaro-Salinas Central Nervous System  Brain Cerebrum o Cerebellum o Brain stem o Limbic system  Nerve Cells that control voluntary acts (neurotransmitters) Copyright © 2023 Wolters Kluwer All Rights Reserved Cerebrum   Two hemis...

Chapter 2 Neurobiologic Theories and Psychopharmacology Dr. Corina Alfaro-Salinas Central Nervous System  Brain Cerebrum o Cerebellum o Brain stem o Limbic system  Nerve Cells that control voluntary acts (neurotransmitters) Copyright © 2023 Wolters Kluwer All Rights Reserved Cerebrum   Two hemispheres o Left-logical reasoning, reading, writing, math o Right-creative thinking, intuition, artistic abilities Four lobes: o Frontal lobe (thought, body movement, memories, emotions, moral behavior)  Schizophrenia, dementia, AHDH o Parietal lobe (taste, touch, spatial orientation) o Temporal lobe (smell, hearing, memory, emotional expression) o Occipital lobe (language, visual interpretation such as depth perception) Copyright © 2023 Wolters Kluwer All Rights Reserved Cerebellum Below cerebrum Center for coordination of movements and postural adjustments Reception, integration of information from all body areas to coordinate movement and posture When dopamine is inhibited in this area, it is associated with lack of smooth coordinated movements (Parkinson’s & dementia) Copyright © 2023 Wolters Kluwer All Rights Reserved Brain Stem Midbrain: reticular activating system (motor activity, sleep, consciousness, awareness) and extrapyramidal system Pons: primary motor pathway Medulla oblongata: vital centers for cardiac, respiratory function Nuclei for cranial nerves III through XII Locus coeruleus: norepinephrine-producing neurons (stress, anxiety, impulsive behavior) Copyright © 2023 Wolters Kluwer All Rights Reserved Limbic System Above brain stem o Thalamus (activity, sensation, emotion) o Hypothalamus (temperature regulation, appetite control, endocrine function, sexual drive, impulsive behavior) o Hippocampus and amygdala (emotional arousal, memory) o Disturbances in this area have been associated with dementia and the poorly controlled emotions and impulses seen with psychotic or manic behavior Copyright © 2023 Wolters Kluwer All Rights Reserved Neurotransmitters (nerve cells)  Chemical substances manufactured in the neuron that facilitate neurotransmission (neuron to neuron) throughout the body (see Fig. 2.3)  Important in right proportions to relay messages; studies showing differences in brains of people with some mental disorders (see Fig. 2.4)  Play role in psychiatric illness and psychotropic medications, including their actions and side effects Copyright © 2023 Wolters Kluwer All Rights Reserved Neurotransmitters #2  Excitatory or inhibitory (see Table 2.1) o Excitatory  Dopamine: complex movements, motivation, cognition, regulation of emotional response  Located primarily in brain stem  Synthesized from tyrosine-a dietary amino acid  Implicated in Schizophrenia, other psychosis & Parkinson’s  Antipsychotic meds work by blocking dopamine receptors  Norepinephrine: attention, learning, memory, sleep, wakefulness, mood regulation  Most prevalent neurotransmitter in the nervous system  AKA noradrenaline  Excess amounts implicated in anxiety disorders  Decreased amounts contribute to memory loss, social withdrawal, and depression  Some antidepressants block the reuptake of norepinephrine  Others inhibit MOA from metabolizing it Copyright © 2023 Wolters Kluwer All Rights Reserved Neurotransmitter #2  Epinephrine: fight-or-flight response in the peripheral nervous system  Limited distribution in the brain  Glutamate: neurotoxic effects at high levels  Glutamate is the most abundant excitatory neurotransmitter in your brain and central nervous system.  Glutamate plays a major role in shaping learning and memory  Implicated in damage caused by stroke, hypoglycemia, hypoxia or ischemia, Alzheimer’s Copyright © 2023 Wolters Kluwer All Rights Reserved Neurotransmitters #3  Excitatory or inhibitory (see Table 2.1)—(cont.) o Inhibitory  Serotonin: food intake, sleep, wakefulness, temperature regulation, pain control, sexual behaviors, regulation of emotions  Found only in the brain  Plays a role in anxiety and mood disorders and schizophrenia  Contributes to the delusions, hallucinations and withdrawn behavior in schizophrenia  Some antidepressants block serotonin reuptake (available longer in the synapse = improved mood)  Gamma-aminobutyric acid (GABA): major inhibitory neurotransmitter; modulation of other neurotransmitters rather than provide a direct stimulus  Benzodiazepines increase GABA function and treat anxiety and induce sleep Copyright © 2023 Wolters Kluwer All Rights Reserved Neurotransmitter #3 o Excitatory or inhibitory  Acetylcholine: sleep-and-wakefulness cycle; signals muscles to become alert Alzheimer’s Disease=decreased acetylcholinesecreting neurons  Neuromodulator: o Histamine (under investigation in mental illnesses)  Some psychotropic drugs block histamine resulting in weight gain, sedation and hypotension o Neuropeptides  Enhance, prolong, inhibit, or limit the effects of principal neurotransmitter Copyright © 2023 Wolters Kluwer All Rights Reserved Brain Imaging Techniques  Computed tomography (CT) o Used to visualize brain’s soft tissue (primary tumors, metastases and determine the size of ventricles) o Some with schizophrenia have enlarged ventricles o = poorer prognosis and marked o negative symptoms  Magnetic resonance imaging (MRI)-magnet and radio waves o Produces more tissue detail and contrast than CT scan o Can show blood flow patterns and edema o Measures the size and thickness of brain structures (schizophrenia can have as much as 7% reduction in cortisol thickness) o May have to sedate a client with claustrophobia unless an open MRI is available o Client with metal implants not a candidate for this procedure Copyright © 2023 Wolters Kluwer All Rights Reserved Advanced Brain Imaging Techniques  Positron emission tomography (PET)-double emission o Examine function of the brain o Client injected with radioactive substances and client asked to do certain activities o Used more for research and not so much in mental diagnosis and treatment  Single-photon emission computed tomography (SPECT)  Limitations o Use of radioactive substances; expense of equipment; client’s inability to tolerate technique if claustrophobic o Procedure lasts hours o Changes in disorders nondetectable with current techniques as some mental disorders such as schizophrenia are at the molecular and chemical level Copyright © 2023 Wolters Kluwer All Rights Reserved Neurobiologic Causes  Genetics and heredity: play role along with nongenetic factors  Types of studies o Twin  o Adoption o studies on identical and fraternal twins Determine a trait among biologic vs. adoptive family members family studies  determine if traits are more common in 1 st degree vs distant family members Studies have not showed that mental illnesses are solely genetically linked  Psychoimmunology (examines the effects psychosocial stressors on the body’s immune system) compromised immune system possibly contributing, especially in genetically at-risk populations Linking a specific stressor to a certain disease has been unsuccessful However, the immune system and brain can influence neurotransmitters  Infections: theories include viruses that alter human genes, viruses during fetal development Copyright © 2023 Wolters Kluwer All Rights Reserved Nurse’s Role in Research and Education  Ensure all clients and families are well informed  Help distinguish between facts and hypotheses  Explain if or how new research may affect client’s treatment or prognosis  Provide information and answer questions Copyright © 2023 Wolters Kluwer All Rights Reserved Question #2 Is the following statement true or false? Single-photon emission computed tomography (SPECT) is considered the best type of brain imaging technique to diagnose disease. Copyright © 2023 Wolters Kluwer All Rights Reserved Answer to Question #2 False Rationale: SPECT is not considered the best type of brain imaging used to diagnose disease. In fact, many of the changes in the brain are not currently detectable with any of the current techniques. Copyright © 2023 Wolters Kluwer All Rights Reserved Psychopharmacology #1  Psychotropic drugs  Efficacy (maximal therapeutic effect)  Potency (amount of drug needed for maximum effect) o Low-potency-require higher doses to achieve efficacy o High-potency- achieve efficacy at lower doses  Half-life (time it takes for half of the drug to be removed from the bloodstream) o Shorter half-life (med given more often) o Longer half-life (med given less often) o For a medication to be excreted completely from the body once it has been D/C is about 5 times it’s half-life  Role of the Food and Drug Administration (FDA) Copyright © 2023 Wolters Kluwer All Rights Reserved Psychopharmacology #2 Off-label use (drug may be effective for treating a disease different from one involved in original testing) Black box warning (serious or life-threatening side effects) Copyright © 2023 Wolters Kluwer All Rights Reserved Principles of Psychopharmacology Effect on target symptoms Adequate dosage for sufficient time Lowest effective dose Lower doses for older adults Tapering rather than abrupt cessation to avoid rebound, recurrence of symptoms, or withdrawal Follow-up care Simple regimen to increase compliance Copyright © 2023 Wolters Kluwer All Rights Reserved Antipsychotic Drugs #1  Antipsychotic drugs (neuroleptic)(see Table 2.3) o Conventional or first generation (e.g., chlorpromazine, fluphenazine, thioridazine, haloperidol, loxapine)  Cause more EPS than other generation antipsychotics o Atypical or second generation (e.g., clozapine, risperidone, olanzapine)  Can increase mortality rates of in elderly client’s with dementia-related psychosis (cardiovascular events, infections)  Cause more weight gain-one reason for non-compliance in clients o Third generation (dopamine system stabilizers; e.g., aripiprazole(abilify))  Enhance dopamine transmission when it is too low and reduce it when it is too high  Control of symptoms w/o side effects  Adjunct med for bipolar and depression Copyright © 2023 Wolters Kluwer All Rights Reserved Antipsychotic Drugs #2  Use: treat symptoms of psychosis o Delusion and hallucinations seen in schizophrenia, schizoaffective and and manic phase of bipolar o OFF LABEL uses:  Treat anxiety and insomnia; aggressive behaviors and other disruptive behaviors on Alzheimer’s pts  Mechanism of action: block dopamine receptors (D1-D5) o Subcategories D2,D3 & D4=associated with mental illness o 1st generation antipsychotics are potent blockers of D2, D3 & D4  o Effective in in treating target symptoms but produce many extrapyramidal side effects because of the blocking of D2 receptors 2nd generation- weak blockers of D2 receptors  Lower extrapyramidal side effects  Inhibit the reuptake of serotonin (similar to antidepressants)  Used to treat the depressive aspect of Schizophrenia Copyright © 2023 Wolters Kluwer All Rights Reserved Antipsychotics: Side Effects #1  Extrapyramidal symptoms (EPSs): o Caused by the blockade of D2 receptors in the midbrain o Geodon (2nd gen) rarely causing EPS  Do not use with other QT prolonging drugs o Acute dystonia (can be painful and frightening to client)  Torticollis(twisted head and neck), opisthotonos(tightness in the entire body with the head back and arch neck), oculogyric crisis (eyes rolled back in the locked position)  Most likely occur in 1st week of txt, clients younger than 40, males and getting high potency drugs  Treatment: anticholinergic drugs ( use with caution in elderly) or diphenhydramine or lowering drug dose  Pseudoparkinsonism (stooped posture, masklike facies, shuffling gait) o Akathisia (restlessness, anxiety, agitation)  Pt needs to be moving around Copyright © 2023 Wolters Kluwer All Rights Reserved Antipsychotics: Side Effects #2  Neuroleptic malignant syndrome (NMS) o Potentially fatal rxn to an antipsychotic med o Rigidity, high fever, unstable B/P, diaphoresis, pallor, delirium elevated enzymes (creatinine phosphokinase) confusion, mute, o Increased risk from high potent, high dose antipsychotic o often occurs in the first 2 weeks of therapy or after an increase in dose o Can occur any other time also- so be vigilant  Tardive dyskinesia (permanent involuntary movements) o Involuntary movements of tongue, facial and neck muscles, upper and lower extremities, lip smacking, blinking, grimacing) o Long term use of conventional antipsychotics o Some success in using levetiracetam (Keppra) for txt in clinical trials  Anticholinergic side effects (e.g., dry mouth, constipation, urinary hesitancy or retention, blurred vision, dry eyes, decreased memory) o Usually decrease after 3-4 weeks Copyright © 2023 Wolters Kluwer All Rights Reserved Antipsychotics: Side Effects #3  Other side effects: o Increased prolactin levels  Breast enlargement and tenderness in men and women, decreased libido, ED, increased risk for breast CA o Weight gain (most likely with second-generation agents, except ziprasidone(Geodon))  Clozapine (Clozaril), Olanzapine (Zyprexa)-most weight gain o Metabolic syndrome  Cluster of conditions that increases risk for heart disease elevated B/P, high glucose levels, High cholesterol) (Obesity, o Cardiovascular adverse effects o Lengthening of QT interval (thioridazine, droperidol, mesoridazine)  o (postural hypotension, palpitations, tachycardia) QT interval more than 500ms is dangerous and can cause death Agranulocytosis (clozapine)  Fever, malaise, ulcerative sore throat, leukopenia (low WBC)  Nurse should consider getting baseline count to monitor WBC weekly  Stop labs 4 weeks after D/C of med Copyright © 2023 Wolters Kluwer All Rights Reserved Antipsychotics: Client Teaching Adherence to regimen Management of side effects o Thirst/dry mouth (sugar-free candy, liquids) o Constipation (dietary fiber, exercise) o Sleepiness/drowsiness (safety measures) Actions for missed dose (take dose if within 4 hours of usual time) Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants #1 Use: major depressive illness, anxiety disorders, depressed phase of bipolar disorder, psychotic depression Off Label-chronic pain, migraines, neuropathies, sleep apnea, eating disorders, panic disorders Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants #2 Four groups (see Table 2.5): o Tricyclic and cyclic compounds o Selective serotonin reuptake inhibitors (SSRIs) o Monoamine oxidase inhibitors (MAOIs) o Other antidepressants Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants #3 Precise mechanism is not known. Major interaction is with monoamine neurotransmitter systems, especially norepinephrine and serotonin. Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants: Side Effects #1 SSRIs o Anxiety, agitation, akathisia, nausea, insomnia, sexual dysfunction o Weight gain but less than other antidepressants o SSRIs better choices for suicidal pts. (venlafaxine, nefazadone, & bupropion) o No risk of lethal overdose o Effective for mild to moderate depression o Cont to monitor pt as pt is at higher risk for suicide as they become more energized on meds o FDA warning of increased risk for suicide in children and adolescents o Full therapeutic effect can take weeks Cyclic antidepressants o Anticholinergic effects (blocks cholinergic receptors)  Common reason pts stop medications o Orthostatic hypotension, sedation, weight gain, tachycardia o Sexual dysfunction-common reason for non compliance o More side effects than SSRIs Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants: Side Effects #2  MAOIs o Daytime sedation, insomnia, weight gain, dry mouth, orthostatic hypotension, sexual dysfunction o Hypertensive crisis (with foods containing tyramine(amino acid))  See Box 2.1 for tyramine rich foods  Lethal with over dose and potential risk for suicidal pts  Other antidepressants o Sedation, headaches (nefazodone, trazodone) o Loss of appetite, nausea, agitation, insomnia (bupropion, venlafaxine) o Priapism (trazodone) Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants: Drug Interactions Serotonin syndrome o MAOI + SSRI o Do not take until the other has cleared the system o Agitation, sweating, fever, tachycardia, hypotension, rigidity, hyperreflexia o Coma, death (extreme reactions) Copyright © 2023 Wolters Kluwer All Rights Reserved Antidepressants: Client Teaching Time of dosage o SSRI first thing in morning unless cause sedation then take at HS o Cyclic compounds at night Actions for missed dose o Take SSRI up to 8 hours after missed dose o Take cyclic within 3 hours of missed dose or omit the day’s dose Safety measures Dietary restrictions with MAOIs (see Box 2.1) Copyright © 2023 Wolters Kluwer All Rights Reserved Mood-Stabilizing Drugs #1 Lithium Anticonvulsants (carbamazepine, valproic acid, gabapentin, topiramate, oxcarbazepine, and lamotrigine) Use: first line agent in treatment of bipolar illness Copyright © 2023 Wolters Kluwer All Rights Reserved Mood-Stabilizing Drugs #2 Mechanism of action o Lithium normalizes reuptake of certain neurotransmitters o Valproic acid and topiramate increase the levels of GABA. o Valproic acid and carbamazepine inhibit the kindling process. (serotonin, norepinephrine, acetylcholine, and dopamine) Copyright © 2023 Wolters Kluwer All Rights Reserved Mood-Stabilizing Drugs: Side Effects #1 Lithium o Nausea, diarrhea, anorexia, fine hand tremor, polydipsia, polyuria, metallic taste in the mouth, fatigue, lethargy; weight gain, acne (side effects that occur later in therapy) o Toxicity: diarrhea, severe vomiting, drowsiness, muscle weakness, lack of coordination (should stop taking med if these occur) o Serum levels should be checked periodically 2-3 days till therapeutic dose achieved, then every week When stable, check levels once a month Carbamazepine and valproic acid: drowsiness, sedation, dry mouth, blurred vision Copyright © 2023 Wolters Kluwer All Rights Reserved Mood-Stabilizing Drugs: Side Effects #2 Carbamazepine: rash, orthostatic hypotension, Valproic acid: weight gain, alopecia, hand tremor, hepatic failure, teratogenic effects (spina bifida) Topiramate: dizziness, sedation, weight loss Copyright © 2023 Wolters Kluwer All Rights Reserved Mood-Stabilizing Drugs: Client Teaching Periodic monitoring of blood levels 12 hours after last dose taken Taking medication with meals Safety measures Copyright © 2023 Wolters Kluwer All Rights Reserved Antianxiety Drugs Use: treatment of anxiety and anxiety disorders, insomnia, obsessive-compulsive disorder (OCD), depression, posttraumatic stress disorder, alcohol withdrawal Benzodiazepines, buspirone (see Table 2.6) Mechanism of action o Benzodiazepines-Mediation of GABA o Buspirone-Partial agonist activity at serotonin receptors which decreases serotonin turnover Copyright © 2023 Wolters Kluwer All Rights Reserved Antianxiety Drugs: Side Effects Benzodiazepines o Physical, psychological dependence o Central nervous system (CNS) depression o Hangover effect o Tolerance Buspirone o Dizziness, sedation, nausea, headache Copyright © 2023 Wolters Kluwer All Rights Reserved Antianxiety Drugs: Client Teaching  Safety measures  Avoidance of alcohol o Can strongly potentiate with benzo  Avoidance of abrupt discontinuation o Benzo withdrawal can be fatal Copyright © 2023 Wolters Kluwer All Rights Reserved Stimulants #1 Amphetamines (methylphenidate(Ritalin), amphetamine(Adderall), dextroamphetamine(Dexedrine) o High potential for abuse o May lead to drug dependance Use: treatment of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents, residual attention-deficit disorder in adults, narcolepsy Copyright © 2023 Wolters Kluwer All Rights Reserved Stimulants #2 Mechanism of action o Cause release of norepinephrine, dopamine, serotonin presynaptically o Block reuptake of neurotransmitters o Inhibitory centers of the brain are stimulated, so the child can better filter distractions Dosage o Divided doses; higher doses for narcolepsy in adults o Doses for treating ADHD vary widely (see Table 2.7). Copyright © 2023 Wolters Kluwer All Rights Reserved Stimulants: Side Effects and Client Teaching Side effects o Anorexia, weight loss, nausea, irritability o Growth and weight suppression Client teaching o Dose after meals o Avoidance of caffeine, sugar, chocolate o Proper storage out of reach of children Copyright © 2023 Wolters Kluwer All Rights Reserved Disulfiram (Antabuse)#1 Use: aversion therapy for alcoholism Mechanism of action: inhibition of enzyme involved with alcohol metabolism o Adverse reaction with alcohol ingestion Side effects: fatigue, drowsiness, halitosis, tremor, impotence, sweating, o Severe S/E-chest pain, dyspnea, hypotension and death (EMERGENCY) Copyright © 2023 Wolters Kluwer All Rights Reserved Disulfiram #2 Drug interactions with phenytoin, isoniazid, warfarin, barbiturates, long-acting benzodiazepines Client teaching: avoidance of alcohol, including common products that may contain it o Shaving cream, deodorant, over-the-counter cough preparations o Make sure pt is aware they are taking this medication and to abstain form alcohol o Never give to an intoxicated client o Monitor liver enzymes Copyright © 2023 Wolters Kluwer All Rights Reserved Cultural Considerations #1 Genetic differences rather than racial or ethnic background are likely to cause slower drug metabolism In the future, a person’s genes may be linked with the most efficacious treatment Avoid making assumptions based on race or ethnicity Ask patient about own past experiences Copyright © 2023 Wolters Kluwer All Rights Reserved Cultural Considerations #2 Increased frequency of herbal medicine use o St. John’s Wort o Kava (depression) (anxiety, insomnia) o Valerian (anxiety, insomnia, depression) o Ginkgo biloba (anxiety) Increased risk for interactions with herbal medicine Copyright © 2023 Wolters Kluwer All Rights Reserved Self-Awareness Issues Clients and families need more than factual information; they need simple and thorough explanations. View chronic mental illness as having remissions and exacerbations, just as chronic physical illnesses do. Remain open to new ideas that may lead to future breakthroughs. Understand that medication noncompliance is often a result of faulty thinking and reasoning related to the illness, not willful misbehavior. 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