What are opioids?

Opioids are naturally occurring and synthetic substances which bind to opioid receptors in the central and peripheral nervous systems. They are primarily prescribed as analgesics in a range of painful conditions.

In this course, we focus specifically on opioids for treating cancer-related pain.

We will use the term “opioid” because it includes all the substances which act on opioid receptors. You will sometimes hear and read the word “opiate”, which refers specifically to substances which are derived from opium, a polymer extracted from the opium poppy. However, in practice the words “opioids” and “opiates” are used interchangeably.

Technically, the designation “narcotic” refers to drugs which induce sleep. In many contexts narcotic is applied to illicit or legally controlled drugs.