With inaccurate dosing of street blotter paper, when mistaken for LSD, or when taken as a powder or liquid, this has resulted in multiple accidental deaths.

[7] One study has shown that 25C-NBOMe blotters have 'hotspots' of the drug and the dosage is not evenly applied over the surface of the paper, which could lead to overdose.

[9] NBOMe-substituted compounds have a diminished absorption rate passing through mucous membranes, but generally remain inactive when taken orally.

[14] Reports of autonomic dysfunction remains prevalent with NBOMe compounds, with most individuals experiencing sympathomimetic toxicity such as vasoconstriction, hypertension and tachycardia in addition to hallucinations.

[15][16][17][18][19] Other symptoms of toxidrome include agitation or aggression, seizure, hyperthermia, diaphoresis, hypertonia, rhabdomyolysis, and death.

[14] NBOMe and NBOHs are regularly sold as LSD in blotter papers,[13][21] which have a bitter taste and different safety profiles.

[29][30][31] The high affinity of NBOMe compounds for adrenergic α1 receptor has been reported to contribute to the stimulant-type cardiovascular effects.

[14] 25C-NBOMe, including the other derivative 25D-NBOMe, reduced the visibility of cardiomyocytes H9c2 cells, and both substances downregulated expression level of p21 (CDC24/RAC)-activated kinase 1 (PAK1), an enzyme with documented cardiac protective effects.

[35][36] 25C-NBOMe was sold as a designer drug in New Zealand in early 2012, but was withdrawn from sale after a statement by Associate Health Minister Peter Dunne that 25C-NBOMe would be considered to be substantially similar in chemical structure to the illegal hallucinogen DOB, and was therefore a Class C controlled drug analogue.