 Serotonergic psychedelics such as tryptamines (e.g., psilocybin, psilocin, , 5-MeO-DMT, bufotenin), lysergamides (e.g., , ergine ()), phenethylamines (e.g., mescaline, 2C-B, 25I-NBOMe), and amphetamines (e.g., , ) are non-selective agonists of serotonin receptors.Their hallucinogenic effects are specifically mediated by activation of the 5-HT2A receptor.Drugs that increase extracellular serotonin levels such as serotonin reuptake inhibitors (e.g., fluoxetine, venlafaxine), serotonin releasing agents (e.g., fenfluramine, ), and monoamine oxidase inhibitors (e.g., phenelzine, moclobemide) are indirect non-selective serotonin receptor agonists.