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-HT2A 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
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