Common side effects include indigestion, trouble sleeping, sexual dysfunction, loss of appetite, dry mouth, rash, and abnormal dreams.Serious side effects include serotonin syndrome, mania, seizures, an increased risk of suicidal behavior in people under 25 years old, and an increased risk of bleeding. If stopped suddenly, a withdrawal syndrome may occur with anxiety, dizziness, and changes in sensation.It is unclear if it is safe in pregnancy.If already on the medication, it may be reasonable to continue during breastfeeding. Its mechanism of action is not entirely clear but believed to be related to increasing serotonin activity in the brain.