💊Pharmacology for Nurses Unit 13 – Psychopharmacologic Drugs

What's This Unit About?

• Focuses on the pharmacology of drugs used to treat psychiatric and neurological disorders
• Covers major classes of psychopharmacologic agents including antidepressants, antipsychotics, anxiolytics, and mood stabilizers
• Explores the mechanisms of action, therapeutic uses, side effects, and nursing considerations for each drug class
• Emphasizes the role of nurses in administering these medications, monitoring patient response, and providing patient education
• Discusses the impact of psychopharmacologic drugs on neurotransmitter systems in the brain (serotonin, dopamine, norepinephrine)
• Highlights the importance of individualized treatment plans based on patient factors and clinical presentation
• Addresses the challenges and ethical considerations associated with psychopharmacologic therapy

Key Terms to Know

• Psychopharmacology: the study of the use of medications in treating mental disorders
• Neurotransmitters: chemical messengers in the brain that transmit signals between neurons (serotonin, dopamine)
• Selective Serotonin Reuptake Inhibitors (SSRIs): a class of antidepressants that increase serotonin levels in the brain (fluoxetine, sertraline)
• Antipsychotics: medications used to treat psychotic disorders such as schizophrenia (haloperidol, risperidone)
• Anxiolytics: drugs used to reduce anxiety symptoms (benzodiazepines, buspirone)
• Mood stabilizers: medications used to treat bipolar disorder and regulate mood fluctuations (lithium, valproic acid)
• Therapeutic index: the ratio between the toxic dose and the therapeutic dose of a drug
• Extrapyramidal symptoms (EPS): movement disorders that can occur as side effects of antipsychotic medications (dystonia, akathisia)

Major Drug Classes

• Antidepressants: used to treat depression and other mood disorders
  • SSRIs (fluoxetine, paroxetine)
  • Serotonin-norepinephrine reuptake inhibitors (SNRIs) (venlafaxine, duloxetine)
  • Tricyclic antidepressants (TCAs) (amitriptyline, nortriptyline)
  • Monoamine oxidase inhibitors (MAOIs) (phenelzine, tranylcypromine)
• Antipsychotics: used to manage psychotic symptoms in schizophrenia and other disorders
  • First-generation (typical) antipsychotics (haloperidol, chlorpromazine)
  • Second-generation (atypical) antipsychotics (risperidone, olanzapine)
• Anxiolytics: used to alleviate anxiety and promote relaxation
  • Benzodiazepines (alprazolam, lorazepam)
  • Non-benzodiazepine anxiolytics (buspirone)
• Mood stabilizers: used to treat bipolar disorder and prevent manic or depressive episodes
  • Lithium
  • Anticonvulsants (valproic acid, lamotrigine)
• Stimulants: used to treat attention deficit hyperactivity disorder (ADHD) (methylphenidate, amphetamines)

How These Drugs Work

• Antidepressants increase the availability of neurotransmitters (serotonin, norepinephrine) in the brain
  • SSRIs block the reuptake of serotonin, leading to increased serotonin levels in the synaptic cleft
  • SNRIs inhibit the reuptake of both serotonin and norepinephrine
  • TCAs block the reuptake of serotonin and norepinephrine and also have anticholinergic effects
  • MAOIs inhibit the enzyme monoamine oxidase, which breaks down neurotransmitters
• Antipsychotics work by blocking dopamine receptors in the brain
  • First-generation antipsychotics primarily block dopamine D2 receptors
  • Second-generation antipsychotics have a broader receptor profile, affecting serotonin and other neurotransmitters
• Anxiolytics enhance the activity of the neurotransmitter gamma-aminobutyric acid (GABA), which has a calming effect on the brain
  • Benzodiazepines bind to GABA receptors and increase the efficiency of GABA neurotransmission
  • Buspirone is a partial agonist at serotonin 5-HT1A receptors and has anxiolytic effects without sedation or dependence
• Mood stabilizers work through various mechanisms to stabilize mood and prevent manic or depressive episodes
  • Lithium's exact mechanism is unknown but may involve modulation of neurotransmitter systems and intracellular signaling pathways
  • Anticonvulsants like valproic acid and lamotrigine have mood-stabilizing effects through multiple mechanisms, including enhancing GABA activity and modulating glutamate and sodium channels

Common Uses and Indications

• Antidepressants are primarily used to treat major depressive disorder and other mood disorders
  • SSRIs and SNRIs are first-line treatments for depression due to their efficacy and relatively mild side effect profile
  • TCAs and MAOIs are used when other antidepressants are ineffective or not tolerated
  • Antidepressants may also be used for anxiety disorders, obsessive-compulsive disorder (OCD), and chronic pain conditions
• Antipsychotics are the mainstay of treatment for schizophrenia and other psychotic disorders
  • They are used to manage positive symptoms (hallucinations, delusions) and negative symptoms (apathy, social withdrawal)
  • Second-generation antipsychotics are often preferred due to their lower risk of extrapyramidal symptoms
  • Antipsychotics may also be used as adjunctive treatment for bipolar disorder, severe depression, or agitation in dementia
• Anxiolytics are used to treat various anxiety disorders, including generalized anxiety disorder (GAD), panic disorder, and phobias
  • Benzodiazepines are fast-acting and effective for acute anxiety or panic attacks but carry risks of sedation, dependence, and withdrawal
  • Buspirone is a safer long-term option for chronic anxiety but may take several weeks to achieve full therapeutic effect
• Mood stabilizers are the primary treatment for bipolar disorder
  • Lithium is the gold standard for treating acute mania and preventing manic and depressive episodes
  • Anticonvulsants like valproic acid and lamotrigine are also effective mood stabilizers and may be used alone or in combination with lithium
  • Mood stabilizers may also be used as adjunctive treatment for treatment-resistant depression or impulsive aggression

Side Effects and Risks

• Antidepressants can cause various side effects, depending on the specific drug class
  • SSRIs and SNRIs may cause nausea, insomnia, sexual dysfunction, and weight gain
  • TCAs can cause anticholinergic effects (dry mouth, constipation, urinary retention), sedation, and cardiac arrhythmias
  • MAOIs have significant dietary restrictions and can cause hypertensive crisis if combined with certain foods or medications
  • All antidepressants carry a black box warning for increased risk of suicidal thoughts and behaviors in young adults
• Antipsychotics can cause a range of side effects, including extrapyramidal symptoms (EPS), metabolic disturbances, and sedation
  • First-generation antipsychotics have a higher risk of EPS, including dystonia, akathisia, and tardive dyskinesia
  • Second-generation antipsychotics are associated with weight gain, diabetes, and dyslipidemia
  • Clozapine, a second-generation antipsychotic, carries a risk of agranulocytosis and requires regular blood monitoring
• Anxiolytics, particularly benzodiazepines, can cause sedation, cognitive impairment, and respiratory depression
  • Long-term use of benzodiazepines can lead to tolerance, dependence, and withdrawal symptoms upon discontinuation
  • Buspirone has a lower risk of sedation and dependence but may cause dizziness, nausea, and headache
• Mood stabilizers have various side effects and require close monitoring
  • Lithium has a narrow therapeutic index and can cause toxicity at high levels, leading to neurological and renal complications
  • Lithium side effects include tremor, hypothyroidism, and nephrogenic diabetes insipidus
  • Anticonvulsants like valproic acid and lamotrigine can cause gastrointestinal disturbances, sedation, and rare but serious skin reactions (Stevens-Johnson syndrome)

Drug Interactions

• Antidepressants can interact with numerous medications, including other psychotropic drugs, cardiovascular medications, and herbal supplements
  • SSRIs and SNRIs can cause serotonin syndrome when combined with other serotonergic agents (MAOIs, triptans)
  • TCAs can interact with anticholinergic medications, increasing the risk of side effects
  • MAOIs have extensive drug interactions and require careful avoidance of sympathomimetic agents and tyramine-containing foods
• Antipsychotics can interact with medications that affect dopamine or serotonin neurotransmission
  • Combining antipsychotics with other dopamine antagonists (metoclopramide) can increase the risk of EPS
  • Antipsychotics can enhance the sedative effects of central nervous system depressants (alcohol, benzodiazepines)
• Anxiolytics, especially benzodiazepines, can have additive effects with other CNS depressants, leading to excessive sedation and respiratory depression
  • Benzodiazepines should be used cautiously with opioids, alcohol, and other sedative medications
  • Buspirone can interact with MAOIs and cause serotonin syndrome
• Mood stabilizers have various drug interactions that require monitoring
  • Lithium levels can be affected by medications that alter renal function (NSAIDs, diuretics) or compete for renal excretion (ACE inhibitors)
  • Valproic acid can displace other highly protein-bound drugs (warfarin) and increase their free concentrations
  • Lamotrigine metabolism can be influenced by medications that induce or inhibit glucuronidation (oral contraceptives, valproic acid)

Nursing Considerations

• Assess patients for the appropriate indications and contraindications before administering psychopharmacologic medications
• Monitor patients closely for therapeutic response, side effects, and adverse reactions
  • Regularly assess vital signs, mental status, and any emergent symptoms
  • Perform laboratory tests as indicated (lithium levels, blood counts, metabolic panels)
• Administer medications accurately and ensure proper dosing and titration schedules
  • Be aware of any special administration requirements (taking with food, avoiding alcohol)
  • Crush or split tablets only when appropriate and as directed
• Implement strategies to minimize and manage side effects
  • Encourage healthy lifestyle habits (diet, exercise) to mitigate metabolic side effects
  • Provide supportive care for gastrointestinal disturbances, dry mouth, or constipation
  • Monitor for and promptly address any signs of EPS or serotonin syndrome
• Collaborate with the healthcare team to develop and adjust individualized treatment plans
  • Communicate any changes in patient status or response to medications
  • Participate in multidisciplinary rounds and care coordination efforts
• Maintain a therapeutic alliance with patients and promote medication adherence
  • Educate patients about their medications, including expected benefits and potential side effects
  • Address any concerns or barriers to adherence and offer strategies for medication management
  • Encourage open communication and trust between patients and the healthcare team

Patient Education Tips

• Provide clear and concise information about the prescribed medication, its purpose, and how it works
  • Use plain language and avoid medical jargon
  • Offer written materials or reliable online resources for reference
• Discuss the expected benefits and timeline for therapeutic response
  • Emphasize that some medications may take several weeks to reach full effectiveness
  • Encourage patients to communicate any changes in symptoms or concerns to their healthcare provider
• Review common side effects and how to manage them
  • Offer practical tips for coping with side effects (taking with food, managing dry mouth)
  • Advise patients when to seek medical attention for severe or persistent side effects
• Stress the importance of taking medications as prescribed and not discontinuing abruptly
  • Explain the risks of non-adherence, including relapse of symptoms or withdrawal effects
  • Suggest strategies for remembering to take medications (pill boxes, alarms, routines)
• Educate patients about potential drug interactions and the need to inform all healthcare providers about their medications
  • Advise patients to consult their pharmacist or prescriber before taking any new medications, including over-the-counter products or herbal supplements
  • Caution patients about the risks of combining psychopharmacologic medications with alcohol or illicit substances
• Encourage patients to maintain regular follow-up appointments and communicate any changes in their condition or concerns
  • Emphasize the importance of monitoring and adjusting treatment plans as needed
  • Reassure patients that their healthcare team is available to support them throughout their treatment journey

Case Studies and Examples

• A 35-year-old woman presents with symptoms of major depressive disorder, including persistent sadness, anhedonia, and sleep disturbances. She is started on sertraline, an SSRI, and experiences improvement in her mood and functioning after 6 weeks of treatment. However, she reports experiencing sexual side effects and is switched to bupropion, which has a lower risk of sexual dysfunction.
• A 22-year-old man is diagnosed with schizophrenia after experiencing auditory hallucinations and paranoid delusions. He is prescribed risperidone, a second-generation antipsychotic, and participates in cognitive-behavioral therapy. His positive symptoms improve, but he develops significant weight gain and hyperglycemia. His treatment plan is adjusted to include metformin for glucose control and a referral to a nutritionist for dietary recommendations.
• A 28-year-old woman with generalized anxiety disorder has been taking alprazolam, a benzodiazepine, for several months. She reports feeling more anxious and having difficulty sleeping when she tries to reduce her dose. Her healthcare provider discusses the risks of long-term benzodiazepine use and works with her to gradually taper the medication while introducing buspirone as a safer long-term option. The patient also engages in cognitive-behavioral therapy to learn coping strategies for managing her anxiety.
• A 45-year-old man with bipolar I disorder has been stabilized on lithium for several years. He presents with tremors, increased thirst, and urinary frequency. Laboratory tests reveal an elevated lithium level and early signs of renal impairment. His lithium dose is adjusted, and he is advised to maintain adequate hydration and avoid NSAIDs, which can increase lithium levels. The patient is monitored closely for resolution of symptoms and improvement in renal function.
• A 60-year-old woman with a history of depression and chronic pain is prescribed duloxetine, an SNRI, for both conditions. She experiences significant improvement in her mood and pain levels but reports dizziness and dry mouth. Her healthcare provider advises her to take the medication with food and offers strategies for managing dry mouth, such as sugar-free gum and frequent sips of water. The patient is encouraged to continue the medication as the side effects are expected to subside with time.