Review of Psychopharmacology: Neurotransmitters and Major Pharmacologic Classes

Primary Neurotransmitters

  • GABA (gamma-aminobutyrate), Dopamine, Serotonin, Norepinephrine, Glutamate, Acetylcholine, Histamine, Tyramine
  • These neurotransmitters are the targets of psychopharmacologic agents and underlie the actions, indications, and side effects discussed below.

Antianxiety Drugs

  • Prototype benzodiazepines: Librium, Valium, Xanax, Klonopin, Ativan
    • Action: Increases GABA (an inhibitory neurotransmitter) leading to decreased neuronal activity
    • Indications: Short-term treatment of anxiety disorders, muscle relaxation, alcohol withdrawal, agitation
    • Therapeutic effects: Sedation, skeletal muscle relaxation
    • Side effects: Sedation (tolerance develops), dizziness, ataxia, highly addictive
    • Primary nursing considerations:
    • Benzodiazepine reversal for overdose = Flumazenil (Romazicon)
    • Teaching: Do not drink alcohol; don’t drive if sedated
    • Eliminated by the liver; may become toxic in the elderly
    • High addiction potential
    • Consideration of half-life in relation to duration of effectiveness and withdrawal syndrome
  • Serotonergics: Buspirone (Buspar)
    • Action not fully sedative; can be non-addictive
    • Key risk: Serotonin syndrome potential
  • Beta blocker: Propranolol
    • Used for stage fright/performance anxiety; non-addicting
  • Tricyclics: OCD indication only for some; Clomipramine (Anafranil) approved for OCD
  • SSRIs (Selective Serotonin Reuptake Inhibitors)
    • OCD approved: Fluvoxamine (Luvox)
    • Other SSRIs: Sertraline (Zoloft), Paroxetine (Paxil), Fluoxetine (Prozac)
  • Alpha-1 Adrenergic Blocker: Prazosin (Minipress)
    • Used for PTSD-related nightmares, irritability, and hyperarousal

Mood Stabilizers

  • Prototype: Lithium Carbonate
    • Action: Exact mechanism unknown; current research suggests lithium stabilizes reuptake mechanisms at the synapse; reduces excitatory dopamine and glutamate neurotransmission and increases inhibitory GABA receptors
    • Rationale: Mania associated with higher glutamate/dopamine and lower GABA; excitotoxicity risk mitigated by lithium; calcium signaling modulation via G-protein receptors
    • Indications: Bipolar Mania
    • Therapeutic effects: Calms mania
    • Side effects: Tremor, dull headache, metallic taste, polydipsia, polyuria, hypothyroidism, weight gain
    • Primary nursing considerations:
    • Takes several weeks to affect acute mania
    • Narrow therapeutic window: extbloodlevel=0.5−1.4extmEq/Lext{blood level} = 0.5-1.4 ext{ mEq/L}
    • Lithium is a salt; body treats it like sodium
    • If sodium is low, kidneys retain lithium (risk of toxicity); if Na is high, lithium levels may fall
    • Labs: time of last dose affects blood lithium level
    • Avoid dehydration; report vomiting/diarrhea or excessive sweating
    • Watch for hypothyroidism symptoms
    • TOXICITY: blood level ≥ 1.5extmEq/L1.5 ext{ mEq/L}; signs include course tremor, GI upset, confusion, ataxia, dysarthria, seizure, coma, death

Mood Stabilizers / Anticonvulsants

  • Prototype: Valproate (Depakote), Carbamazepine (Tegretol), Oxcarbazepine (Trileptal), Lamotrigine (Lamictal), Topiramate (Topamax)
    • Action: Affect sodium and calcium channels, increase GABA, decrease glutamate
    • Indications: Bipolar Mania; Lamictal also for Bipolar depression; agitation/aggressive behavior control
    • Therapeutic range: Depakote 50−100ext,Tegretol8−1250-100 ext{, Tegretol }8-12 (units not specified; require monitoring)
    • Monitoring: Routine blood work to check serum drug levels; liver, pancreas, platelet count, WBC
    • Side effects:
    • Lamictal: severe, life-threatening rash (Stevens-Johnson Syndrome); start low and titrate slowly
    • Depakote: hepatotoxicity, pancreatitis, leukopenia, weight gain, hair loss
    • Tegretol: bone marrow suppression and agranulocytosis, cognitive dulling, tremors; CYP450 inhibitor – avoid grapefruit (increases levels)
    • Nursing considerations:
    • Monitor liver function, pancreatic function, platelet count, WBC
    • Monitor for fever, chills, muscle aches, sore throat (agranulocytosis)
    • Monitor for weight changes
    • Education about hematological symptoms: fever, sore throat, pallor, weakness, infection, easy bruising

Antidepressants

  • (1) Monoamine Oxidase Inhibitors (MAOIs) [Think Diet/Hypertension]
    • Prototype: Nardil, Parnate, Marplan, Selegiline Patch
    • Action: Increases norepinephrine, tyramine, serotonin, and dopamine by preventing breakdown
    • Indications: Atypical depression, depression resistant to other medications
    • Therapeutic effects: Increased energy and lifted depressive symptoms, followed by mood lift
    • Side effects: Hypotension (orthostatic), insomnia, sexual dysfunction, weight gain
    • Primary nursing considerations:
    • Teaching: Low tyramine diet (aged/smoked/fermented foods); avoid decongestants, tramadol, dextromethorphan; inform doctors before surgery
    • Hypertensive crisis: treat hypertension promptly
    • Side effects may abate over time
  • (2) Tricyclics (TCAs) [Think Deadly Overdose]
    • Prototype: Amitriptyline (Elavil), Imipramine (Tofranil), Clomipramine (Anafranil), Nortriptyline (Pamelor), Desipramine (Norpramin), Doxepin (Sinequan)
    • Action: Inhibit reuptake of norepinephrine and/or serotonin
    • Indications: Depression; enuresis, OCD, and other anxiety disorders
    • Therapeutic effects: Energy, mood lift
    • Side effects: Sedation, anticholinergic effects, weight gain, cardiotoxicity
    • Primary nursing considerations:
    • Teaching: Do not drive if sedated; continue meds even if feeling better (often for >1 year)
    • Suicide risk with doses equivalent to ~3 weeks supply
    • Manage side effects (dry mouth, etc.); obtain ECG prior to starting due to cardiotoxicity
  • (3) SSRIs: Serotonin Selective Reuptake Inhibitors
    • Prototype: Fluoxetine (Prozac), Paroxetine (Paxil), Citalopram (Celexa), Fluvoxamine (Luvox), Sertraline (Zoloft)
    • Action: Increase serotonin by preventing reuptake
    • Indications: Depression; some anxiety and eating disorders
    • Therapeutic effects: Increased energy and mood lift; onset typically 4–6 weeks for full effect
    • Side effects: GI symptoms (nausea, vomiting), insomnia, headaches, sweating, drowsiness, cholinergic effects relatively mild; sexual dysfunction; increased bleeding risk
    • Adverse effects / safety concerns: Irritability, GI upset, dry mouth, insomnia, appetite changes, dizziness, urination problems, mood changes, suicidal ideation, homicidal ideation, hyponatremia, thrombocytopenia; Serotonin Syndrome with CNS hyperactivity: agitation, dilated pupils, headache, BP/pulse changes, fever, GI symptoms, myoclonus, shivering, sweating
    • Black Box Warning: Increased risk of agitation and suicidal/homicidal ideation; not indicated for children
    • Primary nursing considerations:
    • Teaching: No driving if sedated; avoid alcohol; do not mix with other serotonergic drugs (Buspirone, St. John’s Wort, St. John’s Wort, S-adenosyl-L-methionine (SAMe))
    • Side effects typically abate over time; monitor hyponatremia and platelet counts
  • (4) SNRI: Serotonin-Norepinephrine Reuptake Inhibitors
    • Examples: Venlafaxine (Effexor), Desvenlafaxine (Pristiq), Duloxetine (Cymbalta)
    • Action: Inhibit reuptake of both serotonin and norepinephrine
    • Indications: Depression and other mood/anxiety disorders

Tetracyclic and Other Antidepressants

  • (5) Tetracyclic: Mirtazapine (Remeron)
  • (7) NDRI: Bupropion (Wellbutrin) – Norepinephrine-Dopamine Reuptake Inhibitor
    • Action: Increases dopamine and norepinephrine
    • Side effects: Agitation, seizures, dry mouth, headache, nausea, GI symptoms, dizziness, weight changes, possible tongue/taste changes
  • (8) NMDA Inhibitor: Esketamine (Ketamine)
    • Forms: Nasal spray and IV
    • Note: Dextromethorphan, an OTC cough medicine, is also an NMDA inhibitor and has abuse potential

Antipsychotics

  • Two categories:
    • 1) Phenothiazines (typical)
    • Think: Stiffness and Positive Symptoms
    • Prototypes:
      • Low potency: Chlorpromazine (Thorazine)
      • High potency: Haloperidol (Haldol)
    • Action: Decrease dopamine activity by blocking D2 receptors
    • Indications: Positive symptoms of psychosis (hallucinations, delusions)
    • Therapeutic effects: Rapid sedation of agitation/aggression; reduction of psychotic symptoms
    • Side effects: EPS (extrapyramidal symptoms) and anticholinergic effects
      • High potency associated with higher EPS and tardive dyskinesia (TD)
      • Low potency associated with lower TD risk
    • Other side effects: postural hypotension, sedation, lowered seizure threshold, photosensitivity, gynecomastia, galactorrhea
    • 2) Atypical Antipsychotics (atypicals)
    • Prototypes: Clozapine (Clozaril), Olanzapine (Zyprexa), Risperidone (Risperdal), Paliperidone (Invega), Ziprasidone (Geodon), Quetiapine (Seroquel), Lurasidone (Latuda), Asenapine (Saphris), Cariprazine (Vraylar), Aripiprazole (Abilify), Ziprasidone (Geodon), Zydis (OL), Aripiprazole long-acting injectables (Abilify Maintenna), Aristada (Aristada), Relprevv, Risperdal Consta, Invega Sustenna/Trinza, Invega Hafedra (note: some brand names in notes vary by region)
    • Indications: Positive and negative symptoms of psychosis
    • Action: Selective blocking of dopamine D2 receptors and glutamate interactions; some serotonin receptor blockade with increased serotonergic activity in certain pathways
    • Therapeutic effects: Reduction of psychotic symptoms with better preservation of personality; many are available as long-acting injectables (LAIs)
    • Important long-acting injectables reductions: Abilify Maintenna, Aristada, Risperdal Consta, Invega Sustenna, Invega Trinza (every 3 months), Invega Hafedra (every 6 months)
    • Benefit over phenothiazines: Effective on positive and negative symptoms; fewer EPS; lower risk of tardive dyskinesia; however metabolic syndrome and weight gain are common; potential gynecomastia and galactorrhea; risk of neuroleptic malignant syndrome and serotonin syndrome; can cause sedation and drooling; orthostatic hypotension; QT prolongation risk with some agents
    • Common adverse effects: Sedation, drooling, hypotension; metabolic syndrome; weight gain; gynecomastia; galactorrhea; neuroleptic malignant syndrome; serotonin syndrome; QT prolongation risk with some agents
    • Black Box Warning: Increased mortality in elderly patients with dementia-related psychosis
  • Antipsychotic Side Effects and Management
    • EPS manifestations: Pseudoparkinsonism, akathisia, acute dystonic reactions, tardive dyskinesia (TD)
    • Neuroleptic Malignant Syndrome (NMS): life-threatening, severe muscular rigidity, autonomic instability, hyperthermia, elevated CPK
    • Metabolic Syndrome: weight gain, dyslipidemia, hyperglycemia
    • TREATMENT of EPS: Reduce antipsychotic dose; add anticholinergic/antihistamine (e.g., Benztropine, Trihexyphenidyl, Diphenhydramine)
    • Anticholinergic side effects: Dry mouth, dizziness, urinary retention, constipation, dilated pupils, blurred vision
    • TD treatment: Valbenazine (Ingrezza), Deutetrabenazine (Austedo) – VMAT2 inhibitors reduce dopamine
  • Primary Nursing Considerations for Antipsychotics
    • Clozapine: weekly WBC monitoring for at least 6 months, then monthly
    • Weight gain concerns: most atypicals cause weight gain and metabolic changes; Olanzapine and Clozapine have the highest risk; Aripiprazole and Ziprasidone have relatively lower weight gain risk but Ziprasidone can prolong QT; monitor cardiovascular status

ADHD Medications

  • Psychostimulants: increase dopamine and norepinephrine
    • Methylphenidate: Ritalin, Concerta, Metadate, Daytrana, Quillivant
    • Dexmethylphenidate: Focalin
    • Lisdexamfetamine: Vyvanse
    • Dextroamphetamine: Dexedrine
    • D and L Amphetamine: Adderall
    • Stimulant side effects: Tics, insomnia, appetite suppression/weight loss, growth suppression, anxiety, headaches, stomach pain, lowered seizure threshold
  • SNRI: Atomoxetine (Strattera)
    • Action: Increases norepinephrine
    • Use: When stimulants are contraindicated
    • Side effects: Irritability, GI upset, dry mouth, insomnia, appetite changes, mood changes, dizziness, urinary problems, sexual dysfunction
  • Alpha Adrenergic Agonists
    • Clonidine (Catapres, Kapvay) and Guanfacine (Intuniv, Tenex)
    • Action: Decreases norepinephrine in the brain, reducing sympathetic arousal
    • Side effects: Sleepiness, hypotension, bradycardia, irritability, depression, hallucinations, thoughts of suicide, drowsiness, dizziness, dry mouth, constipation, nausea, headaches, weight gain

Substance Use Disorder Medications

  • Antabuse: Disulfiram
    • Mechanism: Blocks acetaldehyde dehydrogenase; causes acetaldehyde buildup with alcohol consumption
    • Effect: Alcohol deterrent, does not reduce cravings
    • Important: Must abstain from alcohol for about 14 days after stopping; adverse reactions can be life-threatening
  • Campral: Acamprosate
    • Mechanism: Modulates NMDA transmission; decreases glutamate excitatory activity; increases beta-endorphins
    • Purpose: Reduces alcohol cravings
  • Benzodiazepines for alcohol withdrawal
    • Librium (Chlordiazepoxide), Valium (Diazepam), Ativan (Lorazepam)
    • Action: CNS depressants; potentiate GABA activity to manage withdrawal, prevent seizures and delirium; gradual tapering
  • Topamax: Topiramate
    • Use: Treat cravings/withdrawal and prevent seizures
  • Gabapentin: Neurontin
    • Use: Treat cravings/withdrawal and prevent seizures; potential for dependence
  • Dolophine: Methadone
    • Use: Opioid replacement therapy in methadone clinics
  • Suboxone: Buprenorphine/Naloxone
    • Use: Opioid withdrawal and relapse prevention; buprenorphine is a partial agonist; naloxone is included to deter misuse
  • Narcan: Naloxone
    • Use: Opioid antagonist; rapidly reverses opioid toxicity; nasal spray or injection; sometimes available OTC
  • Revia: Naltrexone
    • Long-acting opioid antagonist (24–48 hours) to prevent relapse in alcohol and opioid dependence
  • Clonidine: Catapres
    • Use: Antihypertensive; autonomic stabilization to ease opioid withdrawal symptoms; used with benzodiazepines and anticonvulsants for withdrawal management

NMDA Receptor Modulators (Additional Note)

  • Esketamine (Ketamine)
    • NMDA receptor antagonist; used for treatment-resistant depression via nasal spray or IV administration

General Nursing Considerations Across Classes

  • Monitor for adverse effects like sedation, EPS, TD, NMS, metabolic syndrome, QT prolongation, and hyponatremia
  • Be aware of drug-drug interactions (e.g., grapefruit with Tegretol/Carbamazepine; SSRIs with serotonergic agents)
  • Monitor vital signs, mental status, and suicidality risk; ensure patient safety
  • Educate about medication adherence, avoiding alcohol, and recognizing signs of toxicity or adverse effects
  • Some medications require lab monitoring (liver enzymes, thyroid function, CBC, WBC counts for clozapine, thyroid for lithium, etc.)
  • Consider pharmacokinetics (half-lives, steady-state levels) and pharmacodynamics (neurotransmitter targets) when planning therapy and monitoring withdrawal or side effects

Note: The above notes capture major and minor points from the transcript, including indications, mechanisms, therapeutic effects, side effects, and nursing considerations for each medication class mentioned. Some brand names and formulations appear in the transcript and are noted here for completeness. For exam purposes, focus on the mechanisms of action, primary indications, key adverse effects, and critical nursing considerations (monitoring, safety, and patient education).