What is pharmakeia, described in the Bible, from which pharmacy or pharmacist derives?

Biblical use of pharmakeia suggests various forms of drug abuse. Those might include drug use in pagan worship, as an addiction, or as a poison used to manipulate and control others.
What is pharmakeia? The Greek word pharmakeia appears in Galatians 5:20 and Revelation 18:23. Terms from the same root word appear in Revelation 9:21, Revelation 21:8, and Revelation 22:15. These are typically translated into English as "sorcery," "witchcraft," or "sorcerer.". Ancient Greek uses of pharmakeia closely mirror the generic modern English word drugs; the same Greek root word produced English terms such as pharmacy and pharmacist.