Antidepressants

Chapter 23: Antidepressants and Mood Stabilizers

Depression

  • Definition: Depression is a mental illness characterized by persistent feelings of sadness, loss of interest or pleasure, and a range of emotional and physical problems.
Etiology
  • Genetic predisposition: Individuals may have a hereditary risk contributing to the likelihood of developing depression.
  • Social and environmental factors: External influences, such as life experiences and surroundings, play a crucial role in the onset of depression.
  • Pathophysiology theories:
    • Decreased levels of monoamine neurotransmitters: Theories posit that low levels of key neurotransmitters contribute to the state of depression.
    • Monoamine neurotransmitters involved:
      • Norepinephrine
      • Serotonin
      • Dopamine
Signs and Symptoms
  • Depressed mood: A persistent state of feeling sad or hopeless.
  • Despair: An overall feeling of bleakness and loss of hope.
  • Weight loss or gain: Changes in appetite leading to significant weight fluctuations.
  • Loss of interest in normal activities: Activities that were once enjoyable become uninteresting.
  • Fatigue: A significant decrease in energy levels.
  • Insomnia or hypersomnia: Difficulty sleeping or excessive sleeping patterns.
  • Decreased ability to think or concentrate: Difficulty focusing or making decisions.
  • Suicidal thoughts: Ideations relating to self-harm or a desire to end one's life.

Types of Depression

  • Reactive Depression:
    • Characteristics: Sudden onset following a precipitating event, such as the death of a loved one.
    • Duration: Typically lasts for several months.
  • Major Depression:
    • May be either primary or secondary to another health problem.
    • Symptoms involve:
    • Loss of interest in work or home activities.
    • Inability to concentrate and complete tasks.
    • Sleep disturbances (insomnia or sleeping too much).
    • Feelings of fatigue and worthlessness.
    • Deep, pervasive sadness.
  • Bipolar Disorder:
    • Characteristics: Characterized by mood swings between manic and depressive states.

Complementary and Alternative Therapy for Depression

  • Herbal treatments:
    • Ginkgo biloba and St. John’s Wort: Used for their potential benefits in managing depression.
    • Precautions:
    • Discontinue herbal products 1 to 2 weeks before surgery.
    • Consultation with healthcare providers before usage is essential.

Major Antidepressants

  • Four primary classes of antidepressant drugs:
    • Tricyclic Antidepressants (TCAs): E.g., Amitriptyline (Elavil)
    • Selective Serotonin Reuptake Inhibitors (SSRIs): E.g., Fluoxetine (Prozac)
    • Serotonin Norepinephrine Reuptake Inhibitors (SNRIs): E.g., Venlafaxine (Effexor)
    • Atypical Antidepressants
    • Monoamine Oxidase Inhibitors (MAOIs)

Tricyclic Antidepressants (TCAs)

  • Action:
    • Blocks the uptake of neurotransmitters, namely norepinephrine and serotonin, resulting in elevated mood and decreased insomnia.
    • Additionally blocks histamine receptors leading to sedation and cholinergic receptors causing anticholinergic effects.
  • Use: Primarily used for major depression.
Side Effects/Adverse Reactions
  • Drowsiness
  • Dizziness
  • Blurred vision
  • Dry mouth and eyes
  • Gastrointestinal distress
  • Urinary retention
  • Sexual dysfunction
  • Weight gain
  • Seizures
  • Sleep-related behaviors
  • Suicidal ideation
  • Orthostatic hypotension
  • Blood dyscrasias (abnormal blood compositions)
  • Cardiotoxicity: Higher doses may lead to dysrhythmias.
  • Extra Pyramidal Symptoms (EPS) and Neuroleptic Malignant Syndrome (NMS): Requires monitoring of therapeutic serum ranges.
Extra Pyramidal Effects (EPS)
  • Pseudoparkinsonism:
    • Symptoms: Stooped posture, shuffling gait, rigidity, bradykinesia, tremors at rest.
  • Acute Dystonia:
    • Symptoms: Facial grimacing, involuntary upward eye movement, muscle spasms in various areas, laryngeal spasms.
  • Akathisia:
    • Symptoms: Restlessness, pacing, trouble standing still.
  • Tardive Dyskinesia:
    • Symptoms: Involuntary movements like protrusion and rolling of the tongue, lip smacking, chewing motions.
Interactions
  • CNS Depressants: Alcohol and other CNS depressants can potentiate CNS depression.
  • MAOIs: Concomitant use may lead to toxic psychosis or cardiotoxicity.
  • Antithyroid drugs: May increase the risk of dysrhythmias.

Selective Serotonin Reuptake Inhibitors (SSRIs)

  • Action: Block the reuptake of serotonin, increasing its availability at synaptic junctions.
  • Uses:
    • Major depression
    • Anxiety disorders, including:
    • Obsessive-Compulsive Disorder (OCD)
    • Panic disorders
    • Phobias
    • Posttrauamatic Stress Disorder (PTSD)
    • Prevention of migraine headaches
    • Decrease premenstrual tension syndrome.
  • Prototype drug: Fluoxetine (Prozac)
  • Other SSRIs: Fluvoxamine (Luvox), Sertraline (Zoloft), Citalopram (Celexa), Escitalopram (Lexapro)
Interactions
  • Increased sedation risk with alcohol and other CNS depressants.
  • Grapefruit Juice: Can cause toxicity when taken with SSRIs.
Side Effects/Adverse Reactions
  • Headache
  • Nervousness
  • Blurred vision
  • Insomnia
  • Dry mouth
  • Gastrointestinal distress
  • Sexual dysfunction
  • Suicidal ideation
  • Notably, side effects often decrease over 1 to 4 weeks.

Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)

  • Action: Inhibit the reuptake of serotonin and norepinephrine.
  • Use: Effective for major depression and generalized anxiety disorder, along with social anxiety disorder.
Interactions
  • Increased risk of hypertensive crisis when combined with MAOIs.
  • Increased sedation risk with alcohol and other CNS depressants.
  • Prototype Drug: Venlafaxine (Effexor)
  • Other SNRIs: Desvenlafaxine, Duloxetine, Levomilnacipran
Side Effects
  • Drowsiness
  • Dizziness
  • Insomnia
  • Headache
  • Euphoria
  • Amnesia
  • Blurred vision
  • Photosensitivity
  • Adverse Effects: Can include tachycardia, hypertension, angioedema, seizures, suicidal ideation.

Atypical Antidepressants

  • Action: Affect one or more neurotransmitters such as serotonin, norepinephrine, and dopamine.
  • Use: Indicated for major depression, reactive depression, and anxiety.
  • Interactions: Should not be taken with MAOIs or within 14 days after discontinuation of MAOIs.
  • Example: Trazodone: Has potential interactions with ketoconazole, ritonavir, and indinavir that may elevate trazodone levels.

Monoamine Oxidase Inhibitors (MAOIs)

  • Action: Inactivate neurotransmitters - norepinephrine, dopamine, epinephrine, and serotonin through the monoamine oxidase enzyme.
  • Use: Effective for depression not managed by TCAs and second-generation antidepressants.
Interactions
  • CNS Stimulants: Those including vasoconstrictors and cold medications can precipitate hypertensive crises when paired with MAOIs.
  • Dietary Restrictions: Foods containing tyramine such as certain cheeses, cream, yogurt, coffee, chocolate, bananas, raisins, Italian green beans, liver, pickled foods, sausage, soy sauce, yeast, beer, and red wines can trigger hypertensive crises.
Side Effects/Adverse Effects
  • Agitation
  • Restlessness
  • Insomnia
  • Anticholinergic effects
  • Orthostatic hypotension
  • Risk for hypertensive crisis due to tyramine interaction.

Nursing Process: Antidepressant Agents

Assessment
  • Evaluate the patient’s baseline vital signs and weight for future comparisons.
  • Obtain a comprehensive health history, including episodes of depression.
  • Assess mental status and for signs of suicidal ideation.
Nursing Diagnosis
  • Social Isolation related to feelings of sadness.
  • Risk for Self-Directed Violence
  • Expected Outcome: Decrease in patient’s depression will be observed.
Nursing Interventions
  • Monitor for signs of depression, mood alterations, insomnia, apathy, or loss of interest in activities.
  • Regularly check vital signs.
  • Watch for drug-drug and food-drug interactions.
  • Provide a list of foods to avoid during treatment.
  • Advise against concurrent consumption of alcohol or other CNS depressants.

Mood Stabilizer: Lithium

  • Definition: A medication used to treat and manage the manic episodes of bipolar disorder.
  • Therapeutic Serum Range: Between 1.0 to 1.5 mEq/L; any levels exceeding 1.5 mEq/L may risk toxicity.
Action
  • Alters ion transport in muscle and nerve cells.
  • Increases receptor sensitivity to serotonin.
Side Effects/Adverse Reactions
  • Headache
  • Drowsiness
  • Dizziness
  • Blurred vision
  • Restlessness
  • Tremors
  • Memory impairment
  • Dry mouth and metallic taste
  • Gastrointestinal distress
  • Hypotension
  • Dysrhythmias
  • Edema of hands and ankles
  • Dehydration
  • Increased urination
  • Blood dyscrasias
  • Neuroleptic Malignant Syndrome (NMS)
  • Serotonin syndrome
  • Potential nephrotoxicity.
Interactions
  • Increased Lithium Levels: Can occur with thiazides, methyldopa, haloperidol, NSAIDs, certain antidepressants, theophylline, and phenothiazines.
  • Decreased Lithium Levels: Lifestyle factors such as caffeine intake and use of loop diuretics can lower lithium levels.

Nursing Process: Lithium

Assessment
  • Assess for suicidal ideation when relevant.
  • Obtain baseline vital signs.
  • Gather health and drug history for comprehensive evaluation.
Nursing Diagnosis
  • Risk for Injury
  • Ineffective Coping related to manic behavior.
  • Expected Outcome: Notable reduction in manic-depressive behavior.
Nursing Interventions
  • Monitor the patient for signs of depression, mood fluctuations, insomnia, apathy, or lack of interest in activities.
  • Track vital signs ongoingly.
  • Consistently monitor lithium levels.
    - Evaluate cardiac health.
  • Advise the patient to avoid caffeine products to maintain stable lithium levels.
  • Encourage maintenance of adequate sodium intake to help manage pharmacokinetics of lithium.