Panamesine


Panamesine is a sigma receptor antagonist that was under development by Merck as a potential antipsychotic for the treatment of schizophrenia in the 1990s but was never marketed. It is a selective antagonist of both sigma receptor subtypes, the σ1 and σ2 receptors. In addition, the major metabolite of the drug, EMD-59983, has high affinity for the sigma receptors and the dopamine D2 and D3 receptors, with potent antidopaminergic activity. Panamesine reached phase II clinical trials for schizophrenia prior to the discontinuation of its development.