Ramelteon is under global development by Takeda Pharmaceuticals as a nonscheduled sleep agent for the treatment of difficulty with sleep initiation, and is marketed under the brand name of Rozerem™ in the United States. In vitro, ramelteon demonstrates affinity and selectivity for human melatonin MT1 and MT2 receptors compared to melatonin. It also demonstrates full agonist activity in cells expressing human MT1 or MT2 receptors relative to melatonin.