Allopregnanolone
neurosteroid
What it isEndogenous neurosteroid and a powerful positive allosteric modulator of GABA-A.
Why it mattersIts fall postpartum is the leading explanation for postpartum depression, and replacing it is what brexanolone does.
What it changesIt acts at extrasynaptic GABA-A receptors that benzodiazepines do not reach, which is why the two classes behave differently.
NO BOXED WARNINGS
Principal riskEndogenous or dietary; no boxed warning applies