Hi, Vicodin and Tramadol both belongs to the group of medications known as opioids and narcotics are used to relieve pain. Vicodin contains both hydrocodone and acetaminophen that is more potent and effective than Tramadol in case of pain relief. But, like other medications, these two medications have their side effects too. The most frequent side effects of Vicodin and Tramadol are loss of appetite, nausea or feeling unwell, vomiting, anxiety, chills, fever, lightheadedness, dizziness, abdominal pain, constipation, itching, rashes, allergic reactions etc. Again, using Vicodin together with Tramadol may lead to serious side effects such as seizures, respiratory distress, coma, even death etc. You should inform your doctor promptly for medical attention if you suffer from such type of side effects during using these medications together. 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,