Mistaking 2C-P for 2C-B: What a Difference a Letter Makes.

2,5-Dimethoxy-4(n)-propylphenethylamine (2C-P) is a synthetic phenethylamine derivative belonging to the large family of the so-called 2C drugs. These compounds can differ significantly in receptor affinity, potency and duration of action, and an important structural difference is the ligand in the 4 position of the phenyl ring, such as propyl in 2C-P or bromine in 2,5-dimethoxy-4-bromophenethylamine (2C-B). The 2C drugs are known for their hallucinogenic properties. We present a case of a 19-year-old male admitted to the emergency department with severe hallucinations, mydriasis, tachycardia, agitation and confusion following the use of a substance sold as 2C-B. By using liquid chromatography-mass spectrometry, the more potent substance 2C-P was detected and quantified. On the basis of two blood sample concentrations, the estimated elimination half-life was 19 h. This case report illustrates and discusses the differences in potency and duration of action of 2C drugs.