Recommendation (from TRS)
Substance identification
N-Pyrrolidino metonitazene (IUPAC name: 2-[(4-methoxyphenyl)methyl]- 5-nitro-1-(2-pyrrolidin-1-ylethyl)-1H-benzoimidazole), also known as metonitazepyne), is a 5-nitro-2-benzylbenzimidazole synthetic opioid.
N-Pyrrolidino metonitazene has been described as a beige powder.
WHO review history
N-Pyrrolidino metonitazene has not previously been reviewed by WHO and is not currently under international control. Information was brought to the attention of WHO that this substance is manufactured clandestinely, poses a risk to public health and has no recognized therapeutic use.
Similarity to known substances and effects on the central nervous system
The chemical structure and pharmacological effects of N-pyrrolidino metonitazene closely resemble those of metonitazene, which is controlled under Schedule I of the Single Convention on Narcotic Drugs of 1961.
Studies in animals have demonstrated that N-pyrrolidino metonitazene is a full agonist at μ-opioid receptors, with greater potency than morphine. Its potency varies from less than to greater than that of fentanyl, depending on the study model. Its effects are blocked by the opioid antagonist, naltrexone.
Dependence potential
No controlled studies of the dependence potential of N-pyrrolidino metonitazene in animals or humans have been reported. As it is a potent μ-opioid receptor agonist, it would be expected to produce dependence similar to those of other opioids, such as morphine and fentanyl.
Actual abuse and/or evidence of likelihood of abuse
In animals, N-pyrrolidino metonitazene showed potent opioid effects and abuse potential, similar to those of morphine and fentanyl.
Multiple deaths have been reported in which N-pyrrolidino metonitazene was analytically confirmed, including one death in which no other opioids were involved. Other substances were detected in all cases. N-Pyrrolidino metonitazene is reported to be administered by injection.
Seizures of N-pyrrolidino metonitazene have been reported in multiple countries in two regions.
Therapeutic usefulness
N-Pyrrolidino metonitazene is not known to have any therapeutic use.
Rationale and recommendation
N-Pyrrolidino metonitazene (IUPAC name: 2-[(4-Methoxyphenyl)methyl]- 5-nitro-1-(2-pyrrolidin-1-ylethyl)-1H-benzoimidazole, also referred to as metonitazepyne, is a synthetic opioid that is liable to abuse and produces ill effects similar to those of other opioids that are controlled under Schedule I of the 1961 Single Convention on Narcotic Drugs. There is evidence that its use causes substantial harm, including death. It has no known therapeutic use.
The Committee recommended that N-pyrrolidino metonitazene (IUPAC name: 2-[(4-methoxyphenyl)methyl]-5-nitro-1-(2-pyrrolidin-1-ylethyl)-1H- benzoimidazole, also referred to as metonitazepyne, be added to Schedule I of the 1961 Single Convention on Narcotic Drugs.
ECDD Recommendation
Inclusion in Schedule I of the 1961 Convention on Narcotic Drugs