Codeine

Opioids cause analgesia (pain relief), mood changes euphoria, addiction, cough suppression and constipation. They act in both the central and peripheral nervous systems, on opioid receptors that occur naturally within the body.

Opioid receptors are located in many different parts of the body, and they are involved in the reward process in the brain. In your body, a number of endorphins bind to and activate opioid receptors.

Examples of medicines which are able to interact with opioid receptors in the human body include: morphine, codeine, fentanyl, methadone, tapentadol, oxycodone and heroin.

Opium was the first opioid used by humans. Opium is a dried product obtained from the seed capsules of the opium poppy Papver somniferum. In Ancient civilisations such as Sumeria, it was known as the 'joy plant'.

It is the active ingredient in opium, All other opioid medicines are derived from the structure of morphine.