25B-NBOMe

25B-NBOMe, also known as 2C-B-NBOMe or Cimbi-36, is a highly potent synthetic psychedelic in the N-benzylphenethylamine family. It is an N-(2-methoxybenzyl) derivative of 2C-B and acts primarily as a serotonin 5-HT_2A receptor agonist. The compound appeared on the recreational drug market around 2010 and has been associated with severe intoxications, seizures and deaths.

Chemistry and history

25B-NBOMe is based on the 2C-B phenethylamine structure, with a bromine atom at the 4-position and methoxy groups at the 2- and 5-positions of the aromatic ring. The nitrogen carries a 2-methoxybenzyl group. This N-benzyl substitution distinguishes it from 2C-B and greatly increases its affinity for serotonin receptors.

The compound was first synthesised during research into N-benzylated phenethylamines and later appeared in online research-chemical markets. It has been found on blotter paper, in powders and in products sold as LSD.

Pharmacology

25B-NBOMe is a potent agonist at the 5-HT_2A receptor, the principal receptor associated with the effects of classical serotonergic psychedelics. N-benzyl substitution can markedly increase the affinity of 2C-series compounds for this receptor. NBOMe compounds may also interact with other serotonin and adrenergic targets, which may contribute to their complex toxicological profile (Pharmacology and toxicology of NBOMe hallucinogens, 2017).

Subjective effects

The PsychonautWiki profile of 25B-NBOMe describes visual changes, altered perception and stimulation as part of the psychedelic experience. These descriptions are largely anecdotal, and clinical reports show that the compound can also produce severe agitation and autonomic disturbance.

Visual and sensory effects

Reported visual effects include geometric patterns, colour enhancement, movement distortions and changes in depth or perspective. Some accounts describe complex closed-eye imagery and an altered sense of the surrounding environment. These effects are consistent with strong 5-HT_2A receptor activation, but their intensity is not predictable from user reports.

Cognitive and emotional effects

Reports describe changes in thought patterns, time perception and emotional intensity. Euphoria and stimulation may occur, but anxiety, confusion, paranoia and disorganised thinking are also reported. Severe intoxication can involve delirium and loss of behavioural control.

Clinical toxicity

A case series described ten patients with analytically confirmed 25B-NBOMe exposure. Hallucinations and violent agitation were common, alongside tachycardia, hypertension, mydriasis and hyperthermia. Seven patients required sedation. Some cases involved rhabdomyolysis and acute kidney injury (Gee and colleagues, 2016).

Two fatal cases involving 25B-NBOMe were reported in Indiana in 2014. The compound was detected in post-mortem blood in one case at 1.59 ng/mL; the second death involved 25I-NBOMe instead (Fatal intoxications with 25B-NBOMe and 25I-NBOMe, 2015).

Toxicity and research limitations

Severe NBOMe intoxication can involve seizures, hyperthermia, rhabdomyolysis, kidney injury and cardiovascular complications. The high receptor potency and small amounts found in some forensic cases make analytical confirmation important. Many reported cases involve uncertain product contents or additional substances, but the clinical evidence establishes that 25B-NBOMe can cause life-threatening toxicity.

Related compounds

25B-NBOMe is related to 25C-NBOMe, 25D-NBOMe and 25C-NBOH. It is the N-benzyl derivative of 2C-B, while the related compounds differ in their ring substituents or benzyl-group chemistry.