Types of Antidepressants and Their Side Effects

Antidepressants are some of the most commonly prescribed medications, so it is important to be familiar with their mechanism of action along with their side effects.

Antidepressants Category 1: Reuptake Inhibitors

There are three major neurotransmitters whose deficiency may contribute to depression: serotonin, norepinephrine, and dopamine. The most common antidepressants are reuptake inhibitors for these neurotransmitters, which increase their availability in neural synapses.

Selective Serotonin Reuptake Inhibitors (SSRIs), such as fluoxetine (Prozac), Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs), such as duloxetine (Cymbalta), and Norepinephrine and Dopamine Reuptake Inhibitors (NDRIs), such as bupropion (Wellbutrin), typically do not have side effects that noticeably impact patients. These side effects may include headache and fatigue. SSRIs and SNRIs also may have sexual side effects, like a low libido; however, that is less common with NDRIs.

Antidepressants Category 2: Tricyclic Antidepressants

Another major category of antidepressants is that of Tricyclic Antidepressants (TCAs), which increase serotonin and norepinephrine while also decreasing another transmitter, acetylcholine. A common TCA is amitriptyline (Elavil). The side effects of TCAs are similar to SSRIs and SNRIs. However, they may be contraindicated in some patients as they can cause hypertension, orthostatic hypotension, and/or heart arrhythmias.

Antidepressants Category 3: Monoamine Oxidase Inhibitors

The most problematic antidepressants in terms of side effects are Monoamine Oxidase Inhibitors (MAOIs), such as Phenelzine (Nardil). MAOIs can have life-threatening interactions with other medications along with foods containing tyramine, such as aged cheeses and meats and pickles. Interactions with tyramine can include a hypertensive crisis, which is a medical emergency. Because of these dangers, MAOIs are typically only prescribed when other types of antidepressants have not been effective.

Other Treatment Options

In addition to these drug categories, there are atypical antidepressants and other drugs used to treat depression. Side effects of these medications vary and should be researched before prescribing to ensure they are appropriate for the patient.