<prompt> all the following drugs are central antagonist drugs used in opiod dependency except ?nalaxonenalmefenenaldemedinenaltraxone  <response>: Opioid Antagonists Naloxone is an example of a opioid antagonist. It is administered intravenously. It can rapidly produce the withdrawal symptoms associated with opioid addiction. Naltrexone is another example of an opioid antagonist. It is more potent than Naloxone and is used i the treatment of alcohol addiction but its mechanism in this treatment is unknown. PERIPHERAL ANTAGONISTS NALOXEGOL ALVIMOPAN NALDEMEDINE PAMORA. ref : kd tripathi 8th ed 