Mood & Affect Pharmacology
1. Major Antidepressant Classifications
Antidepressants modify central nervous system monoamine neurotransmitters (serotonin, norepinephrine, dopamine). All antidepressants carry a Black Box Warning for increased risk of suicidal thoughts and behaviors in children, adolescents, and young adults (under 25) during initial therapy.
SSRIs & SNRIs
Selective Serotonin Reuptake Inhibitors (SSRIs): Fluoxetine, Sertraline, Paroxetine, Citalopram, Escitalopram. First-line therapy due to lower toxicity. Side effects: Sexual dysfunction, weight gain, insomnia. Takes 2–4 weeks for full therapeutic effect.
Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): Venlafaxine, Duloxetine. Used for depression and neuropathic pain. Can increase blood pressure.
Tricyclic Antidepressants (TCAs)
Prototypes: Amitriptyline, Nortriptyline, Imipramine.
Blocks serotonin and norepinephrine reuptake while also blocking cholinergic, histaminergic, and alpha-1 receptors. Anticholinergic side effects: Dry mouth, blurred vision, urinary retention, constipation ("Can't see, can't pee, can't spit, can't poop").
High Overdose Risk: Highly cardiotoxic in overdose (causes fatal lethal cardiac dysrhythmias and QRS widening). Never give more than a 1-week supply to suicidal clients.
High-Alert Food/Drug Interaction
2. MAOIs & Tyramine Dietary Restrictions
Monoamine Oxidase Inhibitors (MAOIs)—such as Phenelzine, Tranylcypromine, and Isocarboxazid—inhibit the enzyme responsible for breaking down norepinephrine, serotonin, dopamine, and dietary tyramine.
Hypertensive Crisis Protocol: Ingesting tyramine while taking an MAOI prevents tyramine degradation, triggering massive norepinephrine release and acute severe vasoconstriction ($\text{BP} > 180/120\text{ mmHg}$). Symptoms: Severe occipital headache, neck stiffness, diaphoresis, palpitations, and intracranial hemorrhage risk.
| Strictly Prohibited Tyramine Foods |
Allowed Low-Tyramine Alternatives |
| Aged cheeses (Cheddar, Swiss, Blue, Gouda, Parmesan) |
Fresh cheeses (Cottage cheese, Cream cheese, Ricotta, Processed American) |
| Cured/aged meats (Salami, Pepperoni, Bologna, Smoked fish) |
Freshly cooked poultry, beef, pork, or fresh fish |
| Fermented soy products (Tofu, Soy sauce, Miso) |
Fresh vegetables, legumes, fruits (except overripe bananas/avocados) |
| Draft beer, unpasteurized beer, red wines (Chianti) |
Commercial canned or bottled non-alcoholic beverages |
*Washout Period Rule: A mandatory 14-day drug-free washout period is strictly required when switching between an MAOI and any other serotonergic agent (SSRI/SNRI) to prevent Serotonin Syndrome.*
Mood Stabilizers
3. Lithium Carbonate Safety & Toxicity Monitoring
Lithium Carbonate is a gold-standard mood stabilizer used for acute mania and long-term maintenance in Bipolar Disorder. It has a narrow therapeutic index requiring rigorous blood level monitoring.
Lithium Serum Levels & Clinical Action Plan
- Therapeutic Maintenance Level: $0.6\text{--}1.2\text{ mEq/L}$ ($1.0\text{--}1.5\text{ mEq/L}$ during acute mania). Draw blood levels 12 hours post-dose (trough level).
- Expected Non-Toxic Side Effects: Fine hand tremor, mild thirst, polyuria, mild nausea, weight gain.
- Mild-to-Moderate Toxicity ($1.5\text{--}2.0\text{ mEq/L}$): Coarse hand tremors, persistent GI distress (diarrhea, vomiting), muscle weakness, drowsiness, ataxia.
- Severe Toxicity ($> 2.0\text{ mEq/L}$): Giddiness, blurred vision, tinnitus, hyperreflexia, seizures, coma, oliguria/renal failure. Levels $> 2.5\text{ mEq/L}$ require emergency hemodialysis.
- Sodium Relationship Rule: Lithium is an inorganic salt that competes with sodium in the renal tubules. Hyponatremia or sodium depletion (via diuretics, sweating, diarrhea, vomiting) causes the kidneys to reabsorb Lithium, triggering severe toxicity. Instruct clients to maintain consistent sodium and fluid intake ($2\text{--}3\text{ L/day}$).
Schizophrenia & Psychosis Therapy
4. Typical vs. Atypical Antipsychotics & EPS Side Effects
Antipsychotics treat schizophrenia, bipolar mania, and psychotic disorders by altering dopamine ($D_2$) and serotonin receptor activity.
First-Generation / Typical (e.g., Haloperidol, Chlorpromazine)
Strong $D_2$ receptor antagonists. Highly effective for positive symptoms (hallucinations, delusions), but carry a high risk of Extrapyramidal Symptoms (EPS).
- Acute Dystonia: Sudden involuntary muscle spasms of neck/face/eyes (oculogyric crisis). Emergency treatment: IV/IM Benztropine or Diphenhydramine.
- Akathisia: Intense motor restlessness (pacing, inability to sit still).
- Parkinsonism: Bradykinesia, mask-like facies, shuffling gait, pill-rolling tremor.
- Tardive Dyskinesia (TD): Late, irreversible involuntary movements of mouth, tongue protrusion, lip smacking. Assessed using the AIMS scale.
Second-Generation / Atypical (e.g., Risperidone, Olanzapine, Clozapine)
Blocks both $D_2$ dopamine and $5\text{-HT}_{2A}$ serotonin receptors. Treats positive and negative symptoms with lower EPS risk.
- Metabolic Syndrome: Significant weight gain, dyslipidemia, hyperglycemia, increased diabetes risk.
- Clozapine Black Box Warning: Risk of severe agranulocytosis (life-threatening leukopenia). Requires baseline and ongoing monitoring of Absolute Neutrophil Count (ANC). Discontinue if $\text{ANC} < 1,000/\text{mm}^3$. Educate client to report sore throat or fever immediately.
Life-Threatening Psychiatric Emergencies
5. Neuroleptic Malignant Syndrome (NMS) vs. Serotonin Syndrome
Nurses must rapidly distinguish between these two medical emergencies, as both present with hyperthermia and autonomic instability.
| Diagnostic Feature |
Neuroleptic Malignant Syndrome (NMS) |
Serotonin Syndrome |
| Causative Agents |
Antipsychotics (Dopamine blockade) |
Serotonergic drugs (SSRIs, SNRIs, MAOIs, St. John's Wort) |
| Neuromuscular Findings |
Extreme "lead-pipe" muscle rigidity, hyporeflexia |
Hyperreflexia, clonus (muscle jerking), tremors, ataxia |
| Autonomic Symptoms |
Severe hyperthermia ($> 104^\circ\text{F}$), diaphoresis, labile BP |
Hyperthermia, diaphoresis, hyperactive bowel sounds (diarrhea) |
| Emergency Treatment |
Stop antipsychotic; cooling blankets; IV fluids; Dantrolene or Bromocriptine |
Stop serotonergic drug; supportive cooling; Cyproheptadine (serotonin antagonist) |
NCLEX / ATI Board Style Question
Clinical Practice Drill
Domain: Mood Stabilizers / Lithium Safety
Question: A nurse is providing discharge teaching to a client diagnosed with bipolar disorder who has been prescribed Lithium Carbonate. Which of the following statements made by the client indicates a correct understanding of the teaching?
A) "I should switch to a low-salt diet to keep my blood pressure down."
Option A
B) "I will make sure to drink 2 to 3 liters of fluid daily and keep my salt intake steady."
Correct Answer ✓
C) "If I experience fine hand tremors, I should stop taking the medication immediately."
Option C
D) "I will take a loop diuretic if I notice swelling in my ankles."
Option D
Clinical Rationale:
Correct Answer: B ("I will make sure to drink 2 to 3 liters of fluid daily and keep my salt intake steady."). Lithium is an inorganic salt excreted by the kidneys. If sodium levels drop (due to low salt intake or excessive sweating/diuretics), the kidneys reabsorb Lithium in place of sodium, causing Lithium toxicity. Maintaining consistent sodium and fluid intake ($2\text{--}3\text{ L/day}$) stabilizes serum Lithium levels.
Distractor Analysis: Switching to a low-salt diet (Option A) or taking a loop diuretic (Option D) causes hyponatremia and prompts renal Lithium reabsorption, inducing toxicity. Fine hand tremors (Option C) are an expected non-toxic side effect that does not warrant stopping the drug abruptly.
Frequently Asked Questions
High-Intent Psych Pharmacology Queries
What is the priority lab monitoring required for Clozapine?
Clients taking Clozapine require baseline and regular ongoing monitoring of the Absolute Neutrophil Count (ANC) due to the risk of life-threatening agranulocytosis. Treatment must be interrupted if the ANC falls below $1,000/\text{mm}^3$.
What is the emergency treatment for acute dystonic reactions from Haloperidol?
Acute dystonia (painful muscle spasms of the face, neck, or tongue) is an acute EPS emergency treated immediately with parenteral anticholinergics such as Benztropine IV/IM or Diphenhydramine IV/IM.
