Some of the most commonly prescribed antidepressants are called reuptake inhibitors. What’s reuptake? It’s the process in which neurotransmitters are naturally reabsorbed back into nerve cells in the brain after they are released to send messages between nerve cells. A reuptake inhibitor prevents this from happening. Instead of getting reabsorbed, the neurotransmitter stays – at least temporarily – in the gap between the nerves, called the synapse.
What’s the benefit? The basic theory goes like this: keeping levels of the neurotransmitters higher could improve communication between the nerve cells – and that can strengthen circuits in the brain which regulate mood.
Selective serotonin reuptake inhibitors (SSRIs) are some of the most commonly prescribed antidepressants available. They include Celexa, Lexapro, Luvox, Paxil, Prozac, and Zoloft. Another drug, Symbyax, is approved by the FDA specifically for treatment-resistant depression. It’s a combination of the SSRI antidepressant fluoxetine (Prozac) and another drug approved for bipolar disorder and schizophrenia called olanzapine (Zyprexa). Aripiprazole (Abilify), quetiapine (Seroquel), and brexpiprazole (Rexulti) have been FDA approved as add-on therapy to antidepressants for depression. Plus, doctors often use other drugs in combination for treatment-resistant depression. Also, the drugs vilazodone (Viibryd) and vortioxetine (Trintellix - formelrly called Brintellix) are among the newest antidepressants that affect serotonin. Both drugs affect the serotonin transporter (like an SSRI) but also affect other serotonin receptors to relieve major depression.
Monoamine oxidase inhibitors (MAOIs) include selegiline (Emsam), isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate). These drugs seem to work a little differently. Monoamine oxidase is a natural enzyme that breaks down serotonin, epinephrine, and dopamine. MAOIs block the effects of this enzyme. As a result, the levels of those neurotransmitters might get a boost.
The downside is that MAOIs also prevent the body’s ability to break down other medicines metabolized by this enzyme (such as Sudafed, or stimulants) – raising the risk for high blood pressure – as well as an amino acid called tyrosine, which is found in certain foods like aged meats and cheeses. MAOIs also shouldn’t be combined with other medicines that can raise serotonin (such as certain migraine medicines, or other antidepressants), because that can cause a buildup of excessive serotonin (called “serotonin syndrome”), which could be life threatening.