L17.Antidepressants

Step 6: Antidepressants

Definition of Depression

  • Depression is a mood disorder with persistent sadness and loss of interest.

  • It is more severe than temporary feelings of sadness ("the blues").

  • Ranges from mild, temporary episodes to severe, persistent depression.

  • Clinical depression (major depressive disorder) affects thinking, feeling, and acting, leading to emotional and physical problems.

Diagnosis of Clinical Depression

  • The DSM-5 is used to diagnose mental disorders.

  • Criteria for clinical depression includes experiencing five or more symptoms in a 2-week period, with at least one symptom being:

    • (1) Depressed mood or (2) Loss of interest or pleasure.

Common Symptoms Include:

  • Depressed mood most of the day, nearly every day.

  • Markedly diminished interest or pleasure in almost all activities.

  • Significant weight change (loss or gain) or significant change in appetite.

  • Observable slowing down of thoughts and physical movement.

  • Fatigue or loss of energy daily.

  • Feelings of worthlessness or inappropriate guilt.

  • Diminished ability to think or concentrate.

  • Recurrent thoughts of death or suicidal ideation.

Classes of Antidepressants

  • Antidepressants are classified based on chemical structure and action in the brain:

    • Tricyclic Antidepressants (TCAs)

    • Monoamine Oxidase Inhibitors (MAOIs)

    • Selective Serotonin Reuptake Inhibitors (SSRIs)

Tricyclic Antidepressants (TCAs)

  • Mechanism of action: Blocks reuptake of norepinephrine and serotonin in the brain, making more available for neurotransmission.

  • Used primarily for depression with unknown cause.

  • Effects include mood elevation, increased alertness, and better sleep.

  • Adverse effects: Weight gain, dry mouth, constipation, confusion, and sedation.

Monoamine Oxidase Inhibitors (MAOIs)

  • MAOIs inhibit monoamine oxidase, which breaks down norepinephrine and serotonin.

  • Developed as early antidepressants, now typically used after other medications fail.

  • Effective for narcolepsy.

Narcolepsy

  • Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, sleep paralysis, hallucinations, and cataplexy episodes.

  • Affects roughly 1 in 2,000 people and often begins in childhood or adolescence.

  • Symptoms: Involuntary sleep during the day, blurred boundaries between awake and asleep, dream-like hallucinations, and disrupted nighttime sleep.

  • Adverse effects of MAOIs: Hypotension, drowsiness, insomnia, hallucinations, diarrhea, nausea, and sexual dysfunction.

Selective Serotonin Reuptake Inhibitors (SSRIs)

  • SSRIs selectively block reuptake of serotonin, causing fewer side effects than TCAs.

  • Usage: Primarily for treating major depression.

  • Adverse effects: Headaches, insomnia, anxiety, nausea, and sexual dysfunction.

Summary of Antidepressants

Tricyclic Antidepressants (generic and trade names):

  • Amitriptyline (Elavil, Vanatrip) - PO

  • Amoxapine (Asendin) - PO

  • Desipramine (Norpramin, Pertofrane) - PO

  • Doxepin (Silenor) - PO

  • Imipramine (Tofranil) - PO

  • Nortriptyline (Pamelor) - PO

  • Protriptyline (Vivactil) - PO

  • Trimipramine (Surmontil) - PO

Monoamine Oxidase Inhibitors:

  • Phenelzine (Nardil) - PO

  • Tranylcypromine (Parnate) - PO

Selective Serotonin Reuptake Inhibitors:

  • Citalopram (Celexa) - PO

  • Escitalopram (Lexapro) - PO

  • Fluoxetine (Prozac) - PO

  • Fluvoxamine (Luvox CR) - PO

  • Paroxetine (Paxil) - PO

  • Sertraline (Zoloft) - PO