Hi. thanks for asking in Healthcare Magic. Nucynta is Tapentadol. It is a newer analgesic (drug used to relieve pain). It has similar action profile like Tramadol. Both Tramadol and Tapentadol are synthetic opioids unlike morphine which is a natural opium alkaloid. It relieves pain through opioid as well as other mechanisms. These drugs relieve mild to moderate short lasting pain but not effective in severe pain. The abuse potential is low. They can cause fits , dizziness, sweating and dry mouth as side effects but only cause minimal breathing difficulty. But still both drugs should not be used in persons having breathing difficulty due to asthma or other reasons. On the other hand Oxycodone is a opioid analgesic is very effective in severe pain. Its abuse potential is higher. It causes respiratory depression and breathing difficulty. The difficulty you are experiencing is mainly due to Oxycodone. It is better not to combine both Oxycodone and Tapentadol. I hope this is useful to you.