Hi, Fetzima contains levomilnacipran which is a type of antidepressant called a serotonin and norepinephrine reuptake inhibitor (SNRI) used to treat major depressive disorder or depression. It works by helping to restore the balance of certain neurotransmitters like serotonin and norepinephrine. Again, Cerenity with tryptophan is a natural comprehensive formula which is used to improve stress perception. It supports a state of calmness and relaxation. It restores healthy sleep cycle, rebuilds neurotransmitter reserves and promotes long term neurotransmitter balance by increasing serotonin and GABA production in the brain. People who are taking antidepressant medications like Fetzima should not take Cerenity with tryptophan without their doctor s supervision. These antidepressant medications like Fetzima could combine with Cerenity with tryptophan to cause serotonin syndrome, a dangerous condition involving mental changes, hot flashes, rapidly fluctuating blood pressure, heart rate and possibly coma. 24 hours after your last Fetzima dose, you can begin treatment by taking Cerenity with tryptophan according to your doctor s advice. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician