O-Desmethyltramadol
O-Desmethyltramadol is an opioid analgesic and the primary active metabolite of tramadol. Since the 2010s, it has been available through the research chemical market as a standalone substance. It acts as a full agonist at the mu-opioid receptor with additional affinity for delta and kappa receptors, producing more typical opioid-like effects than its parent compound. It also exhibits some influence on monoaminergic systems.
Contents
Dosage & Duration
Dosage
Duration
Subjective Effects
Effects vary widely by individual, dose, and context.
Physical
The cognitive effects of O-Desmethyltramadol can be broken down into several components which progressively intensify proportional to dosage. The general head space of codeine is described by many as one of intense euphoria, relaxation, anxiety suppression and pain relief.
Cognitive
The physical effects of O-Desmethyltramadol can be broken down into several components which progressively intensify proportional to dosage.
Reagent Testing
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Pharmacology
Pharmacodynamics
O-Desmethyltramadol acts primarily as a μ-opioid receptor full agonist with substantial affinity (Ki of 19 nM for the racemic mixture), with the (+)-enantiomer exhibiting G-protein biased signaling and considerably higher affinity (Ki of 3 nM). The substance also binds δ- and κ-opioid receptors, though with comparatively much lower affinity. O-DSMT acts as a competitive antagonist at serotonin 5-HT2C receptors at pharmacologically relevant concentrations. The (−)-enantiomer retains some norepinephrine reuptake inhibitor activity, though the potency gap between opioid and monoaminergic activity is substantial enough that this property is functionally minimal for the racemic mixture. Additional in vitro findings include inhibition of muscarinic M1 receptor activity and inhibition of Substance P.
Pharmacokinetics
O-Desmethyltramadol is pharmacologically active without requiring metabolic activation. It is metabolized in the liver into the active metabolite N,O-didesmethyltramadol via CYP3A4 and CYP2B6. The organic cation transporter OCT1, expressed on hepatocyte membranes, mediates uptake of the substance into the liver; individuals with reduced OCT1 activity metabolize it more slowly. Reported elimination half-life values range from approximately 6.7 to 9 hours, with oral peak plasma concentrations reached around 3 hours.
Tolerance
Opioids
Harm Potential
Addiction & Dependence
Psychological
ModerateModerate psychological addiction potential with risk of compulsive redosing. Tolerance develops rapidly with daily use, particularly with multiple daily doses, leading users to chase progressively harder to obtain positive effects, which is identified as a major driver of dependence.
Physical
ModeratePhysical dependence develops within a week of heavy daily use. Withdrawal effects match those of other opioids, including sweating, vomiting, flu-like symptoms, runny nose, chills, lethargy, and headache, though reportedly milder in intensity compared to stronger opioids like diamorphine. At least 3-5 days of moderate to strong flu-like illness should be expected upon cessation.
Toxicity
Long-term chronic use may be associated with elevated hepatic damage markers including α-GST, ALT, AST, ALP, and GGT, particularly in individuals who are CYP2D6 extensive or ultrarapid metabolizers; however, decades of tramadol use in humans has not produced clear evidence of severe hepatotoxicity when used moderately.
Respiratory depression is the primary life-threatening effect in overdose; a sensation of labored breathing may occur at strong doses and represents a danger sign in overdose situations.
Seizure Risk
Seizure risk may be lower than with tramadol, though this has not been definitively confirmed. The (S) enantiomer demonstrated seizure-inducing capability in rats at doses that also caused significant respiratory depression. Studies of tramadol intoxication found O-DSMT plasma levels correlated with seizure onset, though co-ingestion of benzodiazepines or other opioids appeared to reduce seizure risk.
History & Culture
Emergence as a Research Chemical
O-Desmethyltramadol has a limited independent history because it has never been marketed by pharmaceutical companies as a standalone medication, instead being encountered primarily as the principal active metabolite of the analgesic tramadol. Comparatively little research has been conducted on the…
Legality
By Country
Automated synthesisInformation aggregated and synthesized using an autonomous workflow built by Josie Kins.
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