Methadone

Pharmacology

Methadone is a full agonist at the mu (µ) opioid receptor (see Morphine for more details on opioid receptors) in the central and peripheral nervous systems. This produces the typical opiate effects of analgesia, sedation, etc. and slight euphoria, although at higher doses it blocks the euphoric effects that are seen by other opiates such as morphine and heroin. It also seems to have an affinity (ability to bind) to NMDA receptors which are receptors that release the neurotransmitter glutamate. This is thought to make methadone particularly effective in the treatment of neuropathic pain (pain caused by damage to nerves) compared with other opioids.