I’ve been on Pristiq for 2-1/2 years and aside from sweating, I tolerate it well. Once I ran out of meds on a Thursday but was going to see my pdoc on Tuesday and thought, no biggie, I can skip a few days. Tapering off opioids: When and how. If you've taken opioid medications for more than a couple of weeks, it's likely you need to stop soon — and stop slowly, to avoid severe symptoms of withdrawal. Antidepressant withdrawal is possible if you stop taking an antidepressant abruptly — but it's generally preventable. In 2008, Cymbalta became the second drug to receive FDA approval for the treatment of fibromyalgia. It was classified as a serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant. Serotonin syndrome is the accumulation of too much serotonin in your body, resulting in a series of various signs. When an individual takes a combination of medications that contain serotonin (commonly prescribed antidepressants such as Zoloft, Lexapro, both SSRIS and Effexor, an SNRI), they are at a high risk for developing serotonin syndrome.