Title: Xylazine
CAS Registry Number: 7361-61-7
CAS Name: N-(2,6-Dimethylphenyl)-5,6-dihydro-4H-1,3-thiazin-2-amine
Additional Names: 5,6-dihydro-2-(2,6-xylidino)-4H-1,3-thiazine; 2-(2,6-dimethylphenylamino)-4H-5,6-dihydro-1,3-thiazine
Manufacturers' Codes: Bay 1470; Bay Va 1470; Wh-7286
Molecular Formula: C12H16N2S
Molecular Weight: 220.33
Percent Composition: C 65.41%, H 7.32%, N 12.71%, S 14.55%
Literature References: Prepn: O. Behner et al., BE 634552 C.A. 61, 4369b (1964); eidem, DE 1173475 C.A. 61, 13323c (1964); eidem, US 3235550 (1964, 1964, 1966 all to Bayer). Pharmacology: G. Sagner et al., Dtsch. Tieraerztl. Wochenschr. 75, 565 (1968); Kroneberg, Schlossman, Arch. Pharmakol. Exp. Pathol. 268, 348 (1971). Metabolic studies: Duhm et al., Berl. Muench. Tieraerztl. Wochenschr. 82, 104 (1969). Veterinary clinical studies: Clarke, Hall, Vet. Rec. 85, 512 (1969); Burns, McMullan, Vet. Med. 67, 77 (1972).
Properties: Colorless, almost tasteless crystals from benzene-ligroin, mp 140-142°. Also reported as mp 136-139°. Soluble in dilute acids, benzene, acetone, chloroform; sparingly sol in petr ether. Practically insol in water, alkalies. LD50 in mice (mg/kg): 43 i.v.; 121 s.c.; 240 orally; LD50 in rats (mg/kg): 130 orally (Sagner).
Melting point: mp 140-142°; mp 136-139°
Toxicity data: LD50 in mice (mg/kg): 43 i.v.; 121 s.c.; 240 orally; LD50 in rats (mg/kg): 130 orally (Sagner)
Derivative Type: Hydrochloride
CAS Registry Number: 23076-35-9
Trademarks: Narcoxyl (Veterinaria); Rompun (Bayer); Solvazine (Solvay); Xylapan (Chassot); Xylasol (Graeub)
Molecular Formula: C12H16N2S.HCl
Molecular Weight: 256.79
Percent Composition: C 56.13%, H 6.67%, N 10.91%, S 12.49%, Cl 13.81%
Therap-Cat-Vet: Sedative, analgesic, muscle relaxant.
Xylene Xylenol Xylenol Blue Xylidine Xylometazoline

Systematic (IUPAC) name
Clinical data
AHFS/Drugs.com International Drug Names
Legal status Prescription Only (S4) (AU) Veterinary Use
CAS number 7361-61-7 YesY
ATCvet code QN05CM92
PubChem CID 5707
IUPHAR ligand 523
ChemSpider 5505 N
KEGG D08683 YesY
Chemical data
Formula C12H16N2S 
Mol. mass 220.33
 N (what is this?)  (verify)

Xylazine is a drug that is used for sedation, anesthesia, muscle relaxation, and analgesia in animals such as horses, cattle and other non-human mammals. An analogue of clonidine, it is an agonist at the α2 class of adrenergic receptor. Xylazine has recently emerged as a recreational drug, especially in Puerto Rico.[1]

As with other α2 agonists, adverse effects include bradycardia, conduction disturbances, and myocardial depression. Yohimbine (Yobine), tolazoline (commercial name Tolazine), and atipamezole (commercial name Antisedan) can be used to reverse xylazine effects. In veterinary anesthesia, xylazine is often used in combination with ketamine. No formal information in humans is available. Xylazine is sold by Bayer under the brand name Rompun.

Xylazine is also used to shorten the effects of musth on male elephants in Asia.