New Antidepressant Medications

Depression Facts

Depression is one of the most common mental health conditions. In 2014, 6.7% of US adults suffered from at least one depressive episode. Few patients actually discuss depression symptoms with their doctors. Instead, two-thirds of patients with depression present with what are known as somatic symptoms. Somatic symptoms are physical illnesses that cannot be explained by a general medical condition, and can present as, headache, back problems, or chronic pain. After diagnosing depression, the physician may prescribe an antidepressant that will best help the patient while minimizing side effects. 

In the last few years, the FDA approved Brintellix, Viibryd, Fetzima, and Oleptro. These newer antidepressants will be compared to antidepressants already on the market.

Selective Serotonin Reuptake inhibitors (SSRIs)

Selective serotonin reuptake inhibitors (SSRIs) are used as first-line antidepressants because of their efficacy, tolerability, and minimal side effects. SSRIs are also efficient in treating anxiety, which is often part of depression.

SSRI’s treat depression by increasing serotonergic activity; they specifically target serotonin receptors with  little affinity for other types of receptors. Serotonin (5-hydroxytryptamine or 5-HT) is an indoleamine neurotransmitter released in the brain from neurons originating in the brainstem. All SSRI's decrease the action of the pre-synaptic serotonin reuptake pump, by 60 to 80 percent. This increases the length of time that serotonin is available in the synapse and increases postsynaptic serotonin receptor occupancy. 

Older SSRI’S include citalopram (Celexa), fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), escitalopram (Lexapro), fluvoxamine (Luvox). The newest additions are Brintellix (vortioxetine)  and vilazodone (Viibryd).

Clinical Efficacy of SSRIs

Clinical trials comparing one SSRI with another reveal  that they have similar  efficacy. Each antidepressant produces approximately a 60% overall response rate (i.e., at least a 50% reduction in symptoms as a result of treatment).. 

The most recently approved SSRI vortioxetine (Brintellix) additionally binds to -5-HT1A as an agonist, 5-HT1B as a partial agonist and adheres to  serotonin receptors 5-HT_3A, 5-HT₇ as an antagonist. However, there are no comparative studies with Brintellix and other SSRIs to demonstrate its superiority.. Vilazodone (Viibryd) also  acts as a partial agonist on the  serotonin receptor (5-HT_1A) but the medication has not demonstrated superiority over the other medications. 

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