include  paracetamol  (para-acetylaminophenol, also known in the US as acetaminophen), the non-steroidal anti-inflammatory drugs  (NSAIDs) such as the  salicylates , and  opioid  drugs such as  morphine  and  opium . They are distinct from  anesthetics , which reversibly eliminate sensation . Now to safeguard the consumer against possible drug abuse, as some