The Food and Drug Administration has recently approved a new SSRI (Selective Serotonin Reuptake Inhibitor) Vilazodone hydrochloride marketed as Viibryd, according to the American Journal of Nursing.

Vilazodone is used in treating major depressive disorders and is in the same category as other SSRI drugs, such as Zoloft, Lexapro and Prozac. The drug’s labeling carries warnings similar to those on the labels of other SSRI drugs.

This includes elevations in the risks of suicide, serotonin syndrome, neuroleptic malignant syndrome, seizures, abnormal bleeding and activation of mania or hypomania. The medication guide, which comes with the drug prescription says the most common side effects are diarrhea, nausea, vomiting and insomnia.

Serotonin syndrome occurs when you take medications that enhance the chemical serotonin to build up in the body. It is a chemical that your body produces that is needed for your nerve cells and brain to function. Some of the symptoms of this syndrome, according to the Mayo Clinic website are tremors, agitation, sweating, hyperthermia, coma and death.

Currently, there is a black box warning since 2007 on all SSRI Drugs. Dr. Ken Gillman, an Australian clinical pharmacologist, said in a past report in the Journal of Psychopharmacology that neuroleptic malignant syndrome is similar to serotonin syndrome, only it targets the brain chemical dopamine.

“In my capacity as a general physician to the local psychiatric hospital and as a clinical pharmacologist who takes referrals of drug related problems, I have managed over 50 patients with Neuroleptic Malignant Syndrome over the last 12 years” says Gillman.

“From this clinical experience and the literature, I have compiled a table comparing the clinical features of Serotonin Syndrome with those of Neuroleptic Malignant Syndrome,” says Gillman. “From this comparison it can be seen that while there are several features in common, a full physical examination and clinical assessment makes it almost impossible to confuse the two diagnoses.”

The drug was approved at 10, 20 and 40 milligram tablet doses.

It is estimated that about 18 million Americans suffer from major depression, according to the World Health Organization. According to IMS Health, antidepressants were the second-most widely prescribed drug in the U.S. in 2010, after cholesterol-lowering statins.

Approximately 253 million prescriptions for antidepressants were written in 2010, compared with 231 million in 2006.