Emapunil (AC-5216, XBD-173) is an anxiolytic drug which acts as a selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO.

[1][2] This protein has multiple functions, among which is regulation of steroidogenesis,[3][4] particularly the production of neuroactive steroids such as allopregnanolone in the brain.

[5][6][7] In both animal and human trials, emapunil produced fast acting anxiolytic and anti-panic effects, without producing sedation or withdrawal symptoms following cessation of use.

[8][9] Emapunil is also used in its 11C radiolabelled form to map the distribution of TSPO receptors in the brain.

This article about an anxiolytic is a stub.