2-Bromo-LSD

The Chemistry of 2-Bromo-LSD

2-Bromo-LSD was first synthesized by Franz Troxler and Albert Hofmann in 1957.¹ Just like the more well-known compound synthesized by Hofmann, LSD, the synthesis of 2-Bromo-LSD was not an accident. The 1957 paper details their synthesis of various 2-halogenated derivatives of lysergic acid and dihydrolysergic acid.

The Pharmacology of 2-Bromo-LSD

At the time of their 1957 synthesis paper, Hofmann and Troxler were looking for LSD derivatives that could be made into anti-inflammatory and anti-migraine drugs. One characteristic of such compounds would be their ability to block serotonin receptors. In his book LSD – My Problem Child, Hofmann says that he and Troxler “…searched systematically for LSD derivatives without hallucinogenic effects, but with the highest possible activity as serotonin blockers.” ²

2-Bromo-LSD is a serotonin 5-HT_2A receptor antagonist.³ The compound blocks the effects of LSD,⁴ but has no psychological effects on its own.⁵ A 1959 human study reported that some tolerance does develop to 2-Bromo-LSD, and prolonged administration does not cause a significant resistance to the effects of LSD.⁶

The data from receptor binding studies shows that 2-Bromo-LSD has high affinity for serotonin receptors (see table below).

The Applications and Potential of 2-Bromo-LSD

2-Bromo-LSD has not received much research attention. A 2010 open randomized study case series by Karst et al. found 2-Bromo-LSD was effective in improving the frequency and intensity of attacks of cluster headaches.⁷

Receptor Binding Affinity Data