Allopregnanolone

Allopregnanolone
Clinical data
Trade names	Zulresso
Other names	ALLO; ALLOP; SAGE-547; SGE-102; 5α-Pregnan-3α-ol-20-one; 5α-Pregnane-3α-ol-20-one; 3α-Hydroxy-5α-pregnan-20-one; 3α,5α-Tetrahydroprogesterone; 3α,5α-THP, brexanolone (USAN US)
AHFS/Drugs.com	Monograph
MedlinePlus	a619037
License data	US DailyMed: Brexanolone; US FDA: Zulresso;
Routes of; administration	Intravenous
Drug class	Neurosteroids; Antidepressants
ATC code	N06AX29 (WHO) ;
Legal status
Legal status	US: Schedule IV;
Pharmacokinetic data
Bioavailability	Oral: <5%
Protein binding	>99%
Metabolism	Non-CYP450 (keto-reduction via aldo-keto reductases (AKR), glucuronidation via glucuronosyltransferases (UGT), sulfation via sulfotransferases (SULT))
Elimination half-life	9 hours
Excretion	Feces: 47%; Urine: 42%
Identifiers
	IUPAC name 1-[(3R,5S,8R,9S,10S,13S,14S,17S)-3-hydroxy-10,13-dimethyl-2,3,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]ethanone;
CAS Number	516-54-1;
PubChem CID	92786;
DrugBank	DB11859;
ChemSpider	83760;
UNII	S39XZ5QV8Y;
KEGG	D11149;
ChEBI	CHEBI:50169;
ChEMBL	ChEMBL207538;
CompTox Dashboard (EPA)	DTXSID901016239 DTXSID1046342, DTXSID901016239 ;
Chemical and physical data
Formula	C21H34O2
Molar mass	318.501 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES CC(=O)[C@H]1CC[C@@H]2[C@@]1(CC[C@H]3[C@H]2CC[C@@H]4[C@@]3(CC[C@H](C4)O)C)C;
	InChI InChI=1S/C21H34O2/c1-13(22)17-6-7-18-16-5-4-14-12-15(23)8-10-20(14,2)19(16)9-11-21(17,18)3/h14-19,23H,4-12H2,1-3H3/t14-,15+,16-,17+,18-,19-,20-,21+/m0/s1; Key:AURFZBICLPNKBZ-SYBPFIFISA-N;

Allopregnanolone is a naturally occurring neurosteroid which is made in the body from the hormone progesterone. As a medication, allopregnanolone is referred to as brexanolone, sold under the brand name Zulresso, and used to treat postpartum depression. It is given by injection into a vein.

Side effects of brexanolone may include sedation, sleepiness, dry mouth, hot flashes, and loss of consciousness. It is a neurosteroid and acts as a positive allosteric modulator of the GABA_A receptor, the major biological target of the inhibitory neurotransmitter γ-aminobutyric acid (GABA).

Brexanolone was approved for medical use in the United States in 2019. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication. The long administration time, as well as the cost for a one-time treatment, have raised concerns about accessibility for many women.