Psychotropic Medications: Antidepressants (SSRIs), Antipsychotics (EPS), Mood Stabilisers (Lithium)

Psychotropic Medications: Antidepressants (SSRIs), Antipsychotics (EPS), Mood Stabilisers (Lithium)

A practical guide for nurses, clinicians, and students

What Is This?

Psychotropic medications alter brain chemistry to manage mental health disorders. Antidepressants (SSRIs) treat depression and anxiety, antipsychotics manage psychosis and mood disorders, and mood stabilisers (Lithium) control bipolar disorder. Clinicians use them to restore neurotransmitter balance, reduce symptoms, and improve quality of life.

Why use them today? - SSRIs are first-line for depression and anxiety (safer than older antidepressants). - Antipsychotics treat schizophrenia, bipolar mania, and treatment-resistant depression. - Lithium remains the gold standard for long-term bipolar disorder management.

Why It Matters

Mental health disorders affect 1 in 8 people globally (WHO). Psychotropics: - Reduce suicide risk (SSRIs lower rates by ~30% in severe depression). - Prevent hospitalizations (antipsychotics cut relapse rates in schizophrenia by 50%). - Stabilize mood (Lithium reduces bipolar relapse by 60%). - Improve adherence (long-acting injectables increase compliance in psychosis).

Real-world impact: - A patient with major depression may regain function in 4–6 weeks with SSRIs. - A bipolar patient on Lithium may avoid manic episodes for years. - A schizophrenia patient on antipsychotics may live independently instead of in institutional care.

Core Concepts

1. Neurotransmitter Targets

• SSRIs (Selective Serotonin Reuptake Inhibitors):
• Block serotonin reuptake (SERT), increasing serotonin in synapses.
• Takes 2–6 weeks to work (neuroplasticity, not just immediate serotonin boost).
• Antipsychotics:
• Typical (1st-gen): Block D2 dopamine receptors (stronger, more EPS risk).
• Atypical (2nd-gen): Block D2 + serotonin (5-HT2A) (fewer EPS, more metabolic side effects).
• Lithium:
• Modulates inositol depletion, GSK-3?, and BDNF (neuroprotective effects).
• Narrow therapeutic index (0.6–1.2 mEq/L).

2. Side Effect Profiles

3. Extrapyramidal Symptoms (EPS)

• Acute dystonia (muscle spasms, e.g., torticollis)-Treat with benztropine (Cogentin).
• Akathisia (restlessness)-Reduce dose or switch to atypical.
• Parkinsonism (tremor, rigidity)-Amantadine or dose adjustment.
• Tardive dyskinesia (involuntary movements)-Valbenazine (Ingrezza) or clozapine.

4. Monitoring Requirements

• SSRIs: Baseline ECG (if cardiac risk), sexual dysfunction screening.
• Antipsychotics: AIMS test (for EPS), fasting glucose/lipids (metabolic syndrome).
• Lithium:
• Therapeutic drug monitoring (TDM): Levels every 3–6 months (more if unstable).
• Renal/thyroid function: Every 6 months (Lithium causes hypothyroidism in 20%).
• Hydration status: Dehydration-toxicity.

5. Withdrawal & Discontinuation

• SSRIs: Taper over 4–6 weeks (flu-like symptoms, "brain zaps").
• Antipsychotics: Sudden stop-rebound psychosis.
• Lithium: Must taper (abrupt stop-relapse risk).

How It Works

SSRIs: Serotonin Boost

1. Serotonin release-Binds to postsynaptic receptors.
2. SERT (reuptake transporter) normally recycles serotonin.
3. SSRI binds SERT-Blocks reuptake-More serotonin in synapse.
4. Delayed effect: Downregulation of postsynaptic receptors-Mood improvement.

Antipsychotics: Dopamine Blockade

• Mesolimbic pathway (D2 blockade): Reduces positive symptoms (hallucinations).
• Nigrostriatal pathway (D2 blockade): Causes EPS (Parkinsonism).
• Atypicals (e.g., quetiapine): 5-HT2A antagonism-Less EPS, more metabolic effects.

Lithium: Neuroprotection

• Inhibits inositol monophosphatase-Reduces manic episodes.
• Modulates GSK-3?-Neuroprotective (may slow Alzheimer’s progression).
• Narrow therapeutic window: Too low-ineffective; too high-toxicity.

Hands-On / Getting Started

Prerequisites

• Knowledge: Basic pharmacology (ADME), mental health disorders.
• Skills: Medication reconciliation, side effect assessment, lab interpretation.
• Tools: Stethoscope, AIMS scale, lab access (Lithium levels, TSH, glucose).

Step-by-Step: Starting an SSRI

Patient: 32F with major depressive disorder (MDD), no medical comorbidities. Goal: Initiate sertraline (Zoloft) safely.

1. Baseline assessment:
2. Rule out bipolar disorder (SSRIs can trigger mania).
3. Check for serotonin syndrome risk (e.g., concurrent tramadol, St. John’s wort).

4. ECG if cardiac history (SSRIs can prolong QT).

5. Start low, go slow: plaintext Day 1–7: Sertraline 25 mg PO daily (morning) Day 8+: Increase to 50 mg if tolerated

6. Expected side effects: Nausea (transient), headache, insomnia.

7. Monitor: Suicidal ideation (first 2 weeks), sexual dysfunction.

8. Follow-up:

9. 2 weeks: Assess adherence, side effects.
10. 4–6 weeks: Evaluate efficacy (PHQ-9 scale).

11. Adjust: Increase by 25–50 mg every 2 weeks (max 200 mg).

12. Discontinuation (if needed):

13. Taper by 25 mg every 2 weeks to avoid withdrawal.

Step-by-Step: Managing Lithium Toxicity

Patient: 45M on Lithium 900 mg/day, presents with vomiting, ataxia, tremor. Goal: Identify and treat toxicity.

1. Assess:
2. Symptoms: Coarse tremor, confusion, slurred speech.

3. Labs: Lithium level >1.5 mEq/L (toxic), creatinine elevated.

4. Immediate actions:

5. Hold Lithium.
6. IV fluids (0.9% NaCl) to enhance renal excretion.

7. Monitor: ECG (T-wave flattening), electrolytes.

8. If severe (level >2.5 mEq/L):

9. Hemodialysis (removes Lithium rapidly).

10. Supportive care: Antiemetics, seizure precautions.

11. Prevention:

12. Educate patient: Avoid NSAIDs (? Lithium levels), maintain hydration.
13. Monitor: Levels every 3 months if stable.

Common Pitfalls & Mistakes

1. Ignoring Drug Interactions

• SSRIs + NSAIDs/aspirin-? GI bleeding risk.
• Lithium + thiazides-? Lithium levels (toxicity).
• Antipsychotics + anticholinergics-Worsens cognitive side effects. Fix: Use Lexicomp or UpToDate for interaction checks.

2. Overlooking Metabolic Syndrome (Antipsychotics)

• Atypicals (olanzapine, clozapine)-Weight gain, diabetes, hyperlipidemia. Fix:
• Baseline: BMI, waist circumference, fasting glucose, lipids.
• Monitor: Every 3 months for first year, then annually.

3. Rapid Dose Escalation (SSRIs)

• Mistake: Increasing dose too fast-Worsens side effects (e.g., akathisia). Fix: Titrate no faster than every 2 weeks.

4. Not Monitoring Lithium Levels

• Mistake: Assuming "stable" patients don’t need monitoring. Fix:
• Acute mania: Check levels weekly until stable.
• Maintenance: Every 3–6 months.

5. Misdiagnosing EPS as Psychosis

• Mistake: Increasing antipsychotic dose for akathisia-Worsens EPS. Fix:
• Differentiate:
  • Akathisia: Inner restlessness, pacing.
  • Psychosis: Hallucinations, delusions.
• Treat EPS first (e.g., propranolol for akathisia).

Best Practices

For SSRIs

Start with lowest effective dose (e.g., fluoxetine 10 mg, sertraline 25 mg). ? Give in the morning (SSRIs can cause insomnia). ? Warn about sexual dysfunction (affects 30–50%; consider bupropion if problematic). ? Taper slowly (avoid withdrawal syndrome).

For Antipsychotics

Use atypicals first (lower EPS risk, but monitor metabolic effects). ? AIMS test every 6 months (for tardive dyskinesia). ? Consider long-acting injectables (e.g., risperidone LAI) for non-adherent patients. ? Avoid polypharmacy (e.g., two antipsychotics-? side effects).

For Lithium

Check levels 12 hours post-dose (standardized timing). ? Hydrate aggressively (dehydration-toxicity). ? Avoid in renal impairment (GFR <50 mL/min-risk of toxicity). ? Educate on toxicity signs (tremor, nausea, confusion).

Tools & Frameworks

Real-World Use Cases

1. SSRI for Treatment-Resistant Depression

Patient: 28M with MDD, failed fluoxetine 40 mg (no response after 8 weeks). Solution: - Switch to sertraline (different SSRI) or venlafaxine (SNRI). - Augment with bupropion (if partial response). - Consider TMS (transcranial magnetic stimulation) if still refractory.

2. Antipsychotic for Schizophrenia

Patient: 22M with first-episode psychosis, non-adherent to oral meds. Solution: - Start risperidone 2 mg PO daily (titrate to 4–6 mg). - Switch to risperidone LAI (long-acting injectable) after stabilization. - Monitor AIMS scale for EPS.

3. Lithium for Bipolar Disorder

Patient: 35F with bipolar I, frequent manic episodes. Solution: - Start Lithium 300 mg BID (target level 0.8–1.0 mEq/L). - Add valproate if mixed features. - Monitor TSH every 6 months (hypothyroidism risk).

Check Your Understanding (MCQs)

Question 1

A 40-year-old patient on fluoxetine 40 mg daily reports new-onset restlessness and inability to sit still. What is the most likely cause? A) Serotonin syndrome B) Akathisia C) Tardive dyskinesia D) Withdrawal from fluoxetine

Correct Answer: B) Akathisia Explanation: Akathisia is a common extrapyramidal side effect of SSRIs (and antipsychotics), characterized by inner restlessness and pacing. Why the Distractors Are Tempting: - A) Serotonin syndrome-Presents with fever, hyperreflexia, confusion (not just restlessness). - C) Tardive dyskinesia-Involves involuntary movements (e.g., lip smacking), not restlessness. - D) Withdrawal-Causes flu-like symptoms, dizziness (not restlessness).

Question 2

A patient on Lithium 900 mg/day presents with vomiting, coarse tremor, and confusion. Lithium level is 1.8 mEq/L. What is the first step in management? A) Administer activated charcoal B) Start hemodialysis C) Hold Lithium and give IV fluids D) Increase Lithium dose to 1200 mg/day

Correct Answer: C) Hold Lithium and give IV fluids Explanation: Lithium toxicity (level >1.5 mEq/L) requires immediate discontinuation and IV fluids to enhance renal excretion. Why the Distractors Are Tempting: - A) Activated charcoal-Ineffective (Lithium is not absorbed by charcoal). - B) Hemodialysis-Reserved for severe toxicity (>2.5 mEq/L) or renal failure. - D) Increase dose-Would worsen toxicity.

Question 3

A 55-year-old patient on olanzapine 10 mg daily has gained 15 lbs in 3 months and has a fasting glucose of 130 mg/dL. What is the best next step? A) Switch to aripiprazole B) Add metformin C) Increase olanzapine to 15 mg D) Recommend diet and exercise only

Correct Answer: A) Switch to aripiprazole Explanation: Olanzapine is highly associated with metabolic syndrome (weight gain, diabetes). Aripiprazole has a lower metabolic risk. Why the Distractors Are Tempting: - B) Add metformin-May help, but switching antipsychotics is first-line. - C) Increase olanzapine-Would worsen metabolic effects. - D) Diet/exercise alone-Insufficient for significant weight gain.

Learning Path

Beginner (0–3 Months)

• Learn: Basic pharmacology (ADME), neurotransmitter targets.
• Practice: Recognize common side effects (e.g., SSRI nausea, Lithium tremor).
• Resources:
• Book: Stahl’s Essential Psychopharmacology
• Tool: UpToDate (drug interactions, dosing).

Intermediate (3–12 Months)

• Learn: EPS management, Lithium toxicity, metabolic monitoring.
• Practice: Start SSRIs/antipsychotics, interpret Lithium levels.
• Resources:
• Course: Psychopharmacology Institute (CE credits).
• Tool: AIMS scale (for EPS).

Advanced (12+ Months)

• Learn: Treatment-resistant depression, clozap