An analgesic drug , also called simply an analgesic , pain
reliever , or painkiller , is any member of the group of drugs used to
achieve relief from pain (that is, analgesia or pain management). Analgesics
are conceptually distinct from anesthetics, which temporarily reduce, and in
some instances eliminate, sensation, although analgesia and anesthesia are
neurophysiologically overlapping and thus various drugs have both analgesic
and anesthetic effects.