Viibryd helps to treat major depression disorder. It may be prescribed at a low dose, then increased gradually over time. Though it is a serotonin blocker, exactly how the drug resolves depression is still unknown. Viibryd (vilazodone) is a medication used to treat major depressive disorder or depression. It is an antidepressant drug categorized under selective serotonin reuptake inhibitors (SSRIs). Viibryd works by helping in the restoration of the balance of natural substances in the brain. This drug can help in improving the patient’s mood, appetite, energy level and sleep. Viibryd is supplied in the form of capsules or tablets, and it is for oral administration only. While taking this medication, you may experience the following side effects: dizziness, decreased interest in sex, nausea, vomiting among others. If you have been diagnosed with blood clotting disorder, seizures or bipolar disorder, do not take Viibryd.