25B-NBOH

Long QT syndrome, Structural heart disease, Concurrent use of QT-prolonging medications

25B-NBOH carries significant cardiovascular risk based on analog data. Yoon et al. (2022) demonstrated hERG channel inhibition, cardiomyocyte toxicity, and QT prolongation for 25I-NBOH and 25C-NBOH. Clinical tachycardia and hypertension are documented in 25B-NBOH poisonings (Ivory 2022). Individuals with pre-existing cardiac conditions, congenital or acquired long QT syndrome, or concurrent QT-prolonging medications face elevated risk of fatal arrhythmia.

Epilepsy, History of seizures, Reduced seizure threshold

Seizures are a documented complication of NBOMe/NBOH class toxicity. While no 25B-NBOH-specific seizure case has been published, the class-level association is well-established across multiple reviews. Individuals with epilepsy or any condition reducing seizure threshold should not use 25B-NBOH.

Schizophrenia, Schizoaffective disorder, Bipolar I with psychotic features, Family history of psychotic disorders

Personal or family history of psychotic disorders represents a relative contraindication for all potent 5-HT₂A agonists due to the risk of precipitating psychotic episodes. This is a class-level contraindication supported by decades of clinical observation with serotonergic psychedelics.

Pregnancy, Breastfeeding

No reproductive toxicity data exist for 25B-NBOH in any species. Given the compound's potent serotonergic activity, documented sympathomimetic effects, and class-level cardiovascular and neurological toxicity, use during pregnancy or lactation is contraindicated in the absence of safety data.

MAOIs (pharmaceutical), MAOIs (botanical, e.g. ayahuasca)

The combination of potent 5-HT₂A/₂C agonism with MAO-mediated serotonin accumulation creates life-threatening serotonin syndrome risk. This is an absolute contraindication for all potent serotonergic psychedelics. Pelletier et al. (2024) documented serotonin syndrome with 25E-NBOH (structural analog) in a polydrug context.

Tramadol use

Tramadol's serotonergic properties (SERT inhibition) combined with 25B-NBOH's potent 5-HT₂A/₂C agonism carry serotonin syndrome risk. The interaction is classified as dangerous in the substance database. No published case report documents 25B-NBOH + tramadol specifically, but the mechanistic basis is sound and the classification is class-derived.

Lithium use

Lithium combined with 5-HT₂A agonists carries a class-level seizure risk warning. No 25B-NBOH-specific data exist for this combination, but the warning is consistent across the serotonergic psychedelic class and is treated as an absolute contraindication given the severity of potential seizure complications.