Antidepressants Note 2

Selective Serotonin Reuptake Inhibitors (SSRIs)

Overview

  • SSRIs are a class of drugs used primarily as antidepressants in the treatment of major depressive disorder and anxiety disorders. They function by increasing levels of serotonin in the brain.

Generic and Brand Names

  • Citalopram

    • Brand Name: CelexaⓇ

    • Dose: 20 - 40 mg/d

    • Half-life: 35 to 37 hr

  • Escitalopram

    • Brand Name: LexaproⓇ

    • Dose: 10 - 20 mg/d

    • Half-life: 35 to 37 hr

  • Fluoxetine

    • Brand Names: Prozac®, Weekly®, Sarafem®

    • Dose: 20 - 80 mg/d

    • Half-life: 4 to 6 days

  • Paroxetine

    • Brand Name: Paxil®, Paxil CR®

    • Dose: 20 - 50 mg/d

    • Half-life: 26 hr

  • Sertraline

    • Brand Name: Zoloft®

    • Dose: 50 - 200 mg/d

    • Half-life: 24 - 26 hr

  • Fluvoxamine

    • Brand Names: Luvox®, Luvox CR®

    • Dose: 50 - 300 mg/d

    • Half-life: 15 to 20 hr

  • Vilazodone

    • Brand Name: Viibryd®

    • Dose: 10 - 40 mg/d

    • Half-life: 8 to 10 hr

  • Vortioxetine

    • Brand Name: Trintellix®

    • Dose: 10 - 20 mg/d

    • Half-life: 66 hours

Dosage Considerations

  • SSRIs should typically be taken with food for optimal absorption, specifically with meals containing 350 - 500 calories.

  • Blood concentrations of SSRIs in the fasted state can decrease by 50%, potentially resulting in diminished effectiveness.

Side Effects

  • Common side effects include:

    • Seizures

    • Abnormal bleeding

    • Activation of mania and hypomania

    • Hyponatremia

    • Sexual dysfunction

    • Nausea and vomiting

Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)

Overview

  • SNRIs are another class of antidepressants that work by increasing serotonin and norepinephrine levels in the brain. They are used to treat major depressive disorder and other anxiety-related conditions.

Generic and Brand Names

  • Venlafaxine

    • Brand Names: Effexor®, Effexor XR®

    • Dose: 75 - 225 mg/d

    • Half-life: 3 to 7 hrs

  • Desvenlafaxine

    • Brand Name: Pristiq®

    • Dose: 50 mg/d

    • Half-life: Not specified

  • Duloxetine

    • Brand Name: CymbaltaⓇ

    • Dose: 20 - 60 mg/d for depression

    • Half-life: 12 hrs

    • Note: 60-120 mg/d for diabetic peripheral neuropathic pain

  • Levomilnacipran ER

    • Brand Name: Fetzima®

    • Dose: 20 mg for depression

    • Half-life: 12 hrs

Side Effects

  • Known side effects include:

    • Elevated blood pressure and heart rate

    • Seizures

    • Abnormal bleeding

    • Controlled narrow-angle glaucoma

    • Urinary retention

    • Activation of mania/hypomania/mixed episodes

    • Hyponatremia

Discontinuation Syndrome

  • Symptoms of Discontinuation Syndrome may include:

    • Dysphoric mood

    • Irritability

    • Agitation

    • Dizziness

    • Sensory disturbances (e.g., paresthesia resembling electric shock sensations)

    • Anxiety

    • Confusion

    • Headache

    • Lethargy

    • Emotional lability

    • Insomnia

    • Hypomania

    • Tinnitus

    • Seizures

  • These events are generally self-limiting but can include serious symptoms.

Serotonin Syndrome

  • Serotonin syndrome is a potentially life-threatening condition associated with SNRIs and SSRIs when taken alone or, particularly, with other serotonergic drugs (e.g., triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, and St. John's Wort). It may also occur with drugs that impair serotonin metabolism.

  • Symptoms include:

    • Mental Status Changes: Agitation, hallucinations, delirium, coma

    • Autonomic Instability: Tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia

    • Neuromuscular Symptoms: Tremor, rigidity, myoclonus, hyperreflexia, incoordination

    • Gastrointestinal Symptoms: Nausea, vomiting, diarrhea

  • Patients on these medications must be monitored closely for signs of serotonin syndrome.

Other Antidepressants

Overview

  • Other types of antidepressants include inhibitors of norepinephrine and dopamine, tetracyclic agents, and serotonin modulators which serve as alternatives to SSRIs and SNRIs.

Generic and Brand Names

  • Bupropion

    • Brand Names: Wellbutrin®, Wellbutrin SR® (sustained release BID), Wellbutrin XL® (Extended Release QD)

    • Dose: 75 - 450 mg/d

    • Half-life: 8 to 24 hrs

  • Mirtazapine

    • Brand Name: Remeron®

    • Dose: 15 - 45 mg/d

  • Nefazodone

    • Brand Name: Serzone®

    • Dose: 200 - 600 mg/d

  • Trazodone

    • Brand Name: Desyrel®

    • Dose: 200 - 600 mg/d

    • Half-life: 2 to 4 hrs

Side Effects and Implications of Other Antidepressants

  • Side effects vary among these medications, necessitating awareness of each specific drug's profile.

  • Careful monitoring is required to observe for any adverse reactions, especially in patients switching between different classes of antidepressants.