produce dysphoria. nalbuphine was initially designated as a schedule ii controlled substance in the united states along with other opioids upon the introduction of the 1970 controlled substances act. however, its manufacturer, endo laboratories, inc., petitioned the food and drug administration to remove it from schedule ii in 1973, and after a medical and scientific review, nalbuphine was removed completely from the controlled substances act in 1976 and is not a controlled substance in the united states today. for comparison, mor full agonists are all schedule ii in the united states, whereas the mixed kor and mor agonists/antagonists butorphanol and pentazocine are schedule iv in the united states. in canada, most opioids are classified as schedule i, but nalbuphine and butorphanol are both listed as schedule iv substances.