The pain medication Nucynta (tapentadol) treats short-term pain such as what you might experience just after surgery. Each dose lasts four to six hours. Nucynta ER (extended-release tapentadol) is designed to treat continuous pain from, say, cancer or a severe back problem, over a long time period. Each dose lasts 12 hours. Make sure you follow the directions for the specific type of pill you're taking. Nucynta ER is formulated to release its active ingredient slowly, over a long period of time. That makes it more potent than Nucynta; it can harm you if you don't follow your doctor's instructions carefully. Swallow each pill whole: If you crush, chew or dissolve Nucynta ER, you could wind up with the entire day's supply in your system at once, which could cause a fatal overdose.