Vicodin 5 325 mg is one type of pain-reducing medication. It is the the variants are 5-500mg and 75-750 mg. Many people can't find the perfect pain relief medicine. The reason behind they didn't research. Some medicines can interact with Vicodin and cause a serious condition called serotonin syndrome. Be sure your doctor knows if you also take medicine for depression, mental illness, or prevention of nausea and vomiting. Ask your doctor before making any changes in how or when you take your medications.