Antidepressants as they are commonly called, are used to treat depression as well as multiple anxiety disorders including Obsessive Compulsive Disorder (OCD), Panic Disorder and Generalized Anxiety Disorder. There are multiple classes of depression medications including selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs) tricyclics (TCAs), monoamine oxidase inhibitors (MAOIs), dopamine reuptake inhibitors, and a few others that are unique and don’t fit into any of the above classes. I will briefly discuss each group and what makes them unique and what the side effects and risks are.
SSRI’s include fluoxetine (Prozac), escitalopram (Lexapro), sertraline (Zoloft) and a few others. SSRIs are typically used for depressive disorders and anxiety disorders. General warnings with these medications include risk of suicidal thinking (especially in people under age 24), switch to mania (especially in people with a history of mania or hypomania), serotonin syndrome, serotonin withdrawal syndrome and increased risk of bleeding (especially when used with meds like NSAIDS or anticoagulants) and sexual dysfunction (seen in about 30-40% of people).
SSRIs have a very good side effect profile in general and are typically well tolerated, however, they may cause weight gain especially in middle aged women. Paroxetine (paxil) is sedating and thus may help with sleep, but, it stands out in its class as the SSRI that causes the most weight gain. Paroxetine is notorious for its very striking withdrawal syndrome when a patient stops the medication abruptly. Fluvoxamine (Luvox) has been shown to be most effective OCD compared to other SSRI’s,but, twice daily dosing can make taking it more of a chore.
SNRIs include venlafaxine (Effexor), duloxetine (Cymbalta) and levomilnacipran (Fetzima). SNRI’s are effective in treating depression and generalized anxiety, panic disorder, social anxiety as well as a few other conditions. SNRIs such as duloxetine has an indication for fibromyalgia and also has been shown beneficial for peripheral neuropathy and pain syndromes. Duloxetine may cause liver damage particularly in patients with hepatitis or alcoholism and thus should be used with caution in these populations.
TCAs include medications such as amitriptyline, clomipramine, and nortriptyline. TCAs are typically avoided due to high toxicity in overdose and the need for an electrocardiogram (EKG) as they may induce arrhythmias in some people. TCAs are typically used in patients who don’t respond to SSRIs or SNRIs.
MAOIs are include isocarboxazid, phenelzine, and selegiline. The big takeaway is that when on a MAOI, the patient must restrict their diet of tyramine and also avoid use with other antidepressants and multiple other medications due to risk of causing severe and dangerous hypertension. You must wait two weeks after stopping an MAOI before starting another antidepressant. Older studies indicated that MAOIs may have better efficacy compared to TCAs when treating atypical depression (overeating, oversleeping, mood reactivity and rejection sensitivity). They are typically used after multiple other medications have not been found to help.
Other agents that are used include mirtazapine (Remeron), trazodone, vilazodone (Viibryd) and vortioxetine (Brintellix). Mirtazapine is very sedating and will increase the appetite in most people. Trazodone is extremely sedating and almost exclusively used off-label to treat insomnia. Males taking trazodone should be warned of the very rare risk of priapism (approximately 1 in 30,000), or an unwanted and persistent erection of the penis. Patients with priapism should report to their doctor immediately as it needs to be reversed to prevent damage and possible loss of the penis. Vilazodone and vortioxetine are newer agents that were developed to avoid sexual dysfunction that may occur in 30-40% of patients taking SSRIs. The reported rate of sexual dysfunction with vilazodone and vortioxetine respectively is approximately 10% and 1%.
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FDA approved antidepressants: