The present invention provides a dosage form comprising at least one form of tapentadol, with or without a second analgesic, and at least one opioid antagonist, wherein tapentadol is present in an optimal or suboptimal amount and the said antagonist is present in an amount effective to improve the efficacy and or reduce the side effects of tapentadol. The present invention further provides a method of treating pain and pain related conditions by administering to a patient in need thereof, a dosage form comprising at least one form of tapentadol, with or without a second analgesic, and at least one opioid antagonist, wherein tapentadol is present in an optimal or suboptimal amount and the said antagonist is present in an amount effective to improve the efficacy and or reduce the side effects of tapentadol.