Title: Estazolam
CAS Registry Number: 29975-16-4
CAS Name: 8-Chloro-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine
Additional Names: 8-chloro-6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepine
Manufacturers' Codes: D-40TA
Trademarks: Cannoc (Takeda); Esilgan (Takeda); Eurodin (Takeda); Julodin (Takeda); Nemurel (Takeda); Nuctalon (Takeda; Cassenne); ProSom (Abbott); Somnatrol (Takeda)
Molecular Formula: C16H11ClN4
Molecular Weight: 294.74
Percent Composition: C 65.20%, H 3.76%, Cl 12.03%, N 19.01%
Literature References: Prepn: J. B. Hester, DE 2012190; idem, US 3701782 (1970, 1972 to Upjohn); Meguro, Kuwada, Tetrahedron Lett. 1970, 4039; eidem, DE 1955349 (1971 to Toyama), C.A. 74, 88078t (1971); Tawada et al., DE 2114441 (1971 to Takeda), C.A. 76, 34320p (1972); Hester et al., J. Med. Chem. 14, 1078 (1971). Structure-activity studies: R. Nakajima et al., Jpn. J. Pharmacol. 21, 489 (1971). Pharmacology: eidem, ibid. 497; eidem, Takeda Kenkyushoho 31, 349 (1972), C.A. 78, 24138m (1972). Toxicity: Yokotani et al., ibid. 32, 152 (1973), C.A. 79, 133006j (1973). Metabolism: Tanayama et al., Xenobiotica 4, 33-64 (1974); see also ibid. 229, 441. Molecular structure studies: Kamiya et al., Chem. Pharm. Bull. 21, 1520 (1973).
Properties: Crystals from ethyl acetate-Skellysolve B hexanes, mp 228-229°. LD50 orally in male mice, rats and rabbits: 740, 3200, 300 mg/kg (Yokotani).
Melting point: mp 228-229°
Toxicity data: LD50 orally in male mice, rats and rabbits: 740, 3200, 300 mg/kg (Yokotani)
NOTE: This is a controlled substance (depressant): 21 CFR, 1308.14.
Therap-Cat: Sedative, hypnotic.
Keywords: Sedative/Hypnotic; Benzodiazepine Derivatives.
Ester Gums Estradiol Estragole Estramustine Estriol

Systematic (IUPAC) name
Clinical data
AHFS/ monograph
MedlinePlus a691003
Pregnancy cat.  ? (USA)
Legal status Schedule IV (US)
Routes Oral
Pharmacokinetic data
Bioavailability 93%
Metabolism Hepatic
Half-life 10-24 hours
Excretion Renal
CAS number 29975-16-4 YesY
ATC code N05CD04
PubChem CID 3261
DrugBank DB01215
ChemSpider 3146 YesY
KEGG D00311 YesY
Chemical data
Formula C16H11ClN4 
Mol. mass 294.7
 YesY (what is this?)  (verify)

Estazolam[1] (marketed under the brand names ProSom, Eurodin) is a benzodiazepine derivative drug developed by Upjohn in the 1970s.[2] It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. Estazolam is an intermediate-acting oral benzodiazepine.

It is commonly prescribed for short-term treatment of insomnia.