I have been prescribed 100 mg Prolonged Release Nucynta/Tapentadol to take every 12 hours. I'm on it a week now, but no improvement in the chronic pain caused by scoliosis. Does the drug need to build up in your body to treat the pain - the pharmacist said not - that it should work per dosage, therefore I should have got relief from the 1st dose but I didn't/haven't. Can anyone shine any light please?? Much appreciated and many thanks for your responses in advance. It seems pointless to keep taking it if it's not working... and it's very expensive here in Europe, I've to pay about 150 dollars for a month's supply.