Allopregnanolone is a neurosteroid metabolite of progesterone. It is an allosteric modulator of inhibitory γ-aminobutyric acid (GABA-A) receptors on neural stem cells and other cell types in the brain. Allopregnanolone has effects similar to those of other positive allosteric modulators of the GABA action at GABAA receptor such as the benzodiazepines, including anxiolytic, sedative, and anticonvulsant activity. A solution of allopregnanolone, SAGE-547 is an intravenous allosteric modulator of both synaptic and extrasynaptic γ-aminobutyric acid type A (GABAA)receptors. It's believed that allopregnanolone is effective as an anticonvulsant when prolonged seizure activity has become resistant to benzodiazepine treatment. Under the names brexanolone and SAGE-547, allopregnanolone is under development by SAGE Therapeutics as an intravenously administered drug for the treatment of super-refractory status epilepticus, postpartum depression, and essential tremor. Allopregnanolone is in phase III trials for the treatment of super-refractory status epilepticus (SRSE) and postpartum depression.