15.3 : Antidepressant Drugs: Tricyclics, SSRIs, and SNRIs

Tricyclic Antidepressants (TCAs), including Desipramine (Norpramin), Imipramine (Tofranil), Clomipramine (Anafranil), and Amitriptyline (Elavil), inhibit serotonin and norepinephrine reuptake and also block other receptors. They are used for depression, pain conditions, and insomnia. Common adverse effects include anticholinergic effects, sedation, orthostatic hypotension, and weight gain. They have a narrow therapeutic window and so require plasma-level monitoring. Abrupt discontinuation can cause a cholinergic rebound and flu-like symptoms. Drug interactions are possible, particularly with MAOIs.

Selective Serotonin Reuptake Inhibitors (SSRIs), such as Fluoxetine (Prozac) and Paroxetine (Zoloft), primarily inhibit serotonin reuptake and treat depression, OCD, anxiety and panic disorder, and bulimia nervosa. Common adverse effects include headache, sweating, gastrointestinal effects, and sexual dysfunction. They can be sedating or activating, depending on the specific drug. Caution is advised when using SSRIs in children and teenagers due to the potential worsening of depression and suicidal thinking.

Serotonin-norepinephrine reuptake Inhibitors (SNRIs), including Venlafaxine (Effexor), Reboxetine (Edronax) and Duloxetine (Cymbalta), inhibit both serotonin and norepinephrine reuptake. They are used for depression, anxiety disorders, pain syndromes, and fibromyalgia. Adverse effects include nausea, headache, sexual dysfunction, dizziness, insomnia, sedation, and constipation. Abrupt discontinuation may cause a discontinuation syndrome.