O-Desmethyltramadol

O-Desmethyltramadol (O-DSMT) is an opioid analgesic and the main active metabolite of tramadol. Tramadol is demethylated by the liver enzyme CYP2D6 in the same way as codeine, and so similarly to the variation in effects seen with codeine, individuals who have a less active form of CYP2D6 ("poor metabolizers") will tend to get reduced analgesic effects from tramadol. Conversely, "ultra-rapid metabolizers" (people with a specific genetic variation) get increased effects. In addition to acting as a weak mu-opioid receptor agonist, O-DSMT also increases the release of serotonin and inhibits the reuptake of norepinephrine, making it have a minor antidepressant effect in addition to the analgesic effects.

Pharmacology

O-DSMT is a more potent analgesic than tramadol. It is also a reuptake inhibitor of norepinephrine and serotonin, which contributes to its analgesic effects. The effects of O-DSMT last for about six hours, and it has a half-life of eight hours.

Side Effects

The side effects of O-DSMT are similar to those of other opioids and include itching, nausea, dizziness, and respiratory depression. Because of the serotonin increase caused by O-DSMT, it also carries a risk of serotonin syndrome, a potentially life-threatening condition.

Legal Status

The legal status of O-DSMT varies by country, but it is a controlled substance in many places due to its potential for abuse and addiction. In the United States, it is a Schedule II controlled substance, which means it has a high potential for abuse and its use can lead to severe psychological or physical dependence.

See Also

• Tramadol
• Opioid
• Analgesic
• Serotonin syndrome