Elzasonan
# Elzasonan

Elzasonan (CP-448,187) is a selective $5-HT_{1B}$ and $5-HT_{1D}$ receptor antagonist that was under development by Pfizer for the treatment of depression but was discontinued, possibly due to poor efficacy. By preferentially blocking $5-HT_{1B}$ and $5-HT_{1D}$ autoreceptors, elzasonan is thought to enhance serotonergic innervations originating from the raphe nucleus, thereby improving signaling to limbic regions like the hippocampus and prefrontal cortex and ultimately resulting in antidepressant effects.

