Noribogaine is an organic heteropentacyclic compound derived from ibogamine, where the indole hydrogen para to the indole nitrogen is replaced by a hydroxy group. It is the primary and long-lived metabolite of ibogaine, a psychoactive indole alkaloid found in the African rainforest shrub Tabernanthe iboga. Noribogaine functions as a psychotropic drug, serotonin uptake inhibitor, NMDA receptor antagonist, and kappa-opioid receptor agonist. It is a monoterpenoid indole alkaloid, an organic heteropentacyclic compound, a tertiary amino compound, and a secondary amino compound. It is functionally related to ibogaine and is the conjugate base of noribogaine(1+).