Title: Azaperone
CAS Registry Number: 1649-18-9
CAS Name: 1-(4-Fluorophenyl)-4-[4-(2-pyridinyl)-1-piperazinyl]-1-butanone
Additional Names: 4¢-fluoro-4-[4-(2-pyridyl)-1-piperazinyl]butyrophenone; 1-[3-(4-fluorobenzoyl)propyl]-4-(2-pyridyl)piperazine
Manufacturers' Codes: R-1929
Trademarks: Stresnil (Janssen); Suicalm (Janssen)
Molecular Formula: C19H22FN3O
Molecular Weight: 327.40
Percent Composition: C 69.70%, H 6.77%, F 5.80%, N 12.83%, O 4.89%
Literature References: Prepn: Janssen, US 2979508 (1961). Synthesis of labeled compound: Soudijn, van Wijngaarden, J. Lab. Comp. 4, 159 (1968). Distribution and metabolism studies in rat and pig: Heykants et al., Arzneim.-Forsch. 21, 982, 1263, 1357 (1971). Veterinary clinical studies: Symoens, van den Brande, Vet. Rec. 85, 64 (1969). Crystal structure: M. H. J. Koch et al., Acta Crystallogr. 33B, 1975 (1977).
Properties: Crystals, mp 73-75°.
Melting point: mp 73-75°
Therap-Cat-Vet: Sedative; tranquilizer.
Azaserine Azasetron Azatadine Azelaic Acid Azelastine

Azaperone structure.svg
Systematic (IUPAC) name
Clinical data
AHFS/ International Drug Names
Legal status  ?
Routes intramuscular injection
Pharmacokinetic data
Metabolism hepatic
Half-life 4 hours
CAS number 1649-18-9 N
ATCvet code QN01AX91 QN05AD90
PubChem CID 15443
ChemSpider 14695 YesY
KEGG D02620 YesY
Chemical data
Formula C19H22FN3O 
Mol. mass 327.396 g/mol
Physical data
Melt. point 90–95 °C (194–203 °F)
 N (what is this?)  (verify)

Azaperone (Stresnil, Fluoperidol) is a pyridinylpiperazine and butyrophenone neuroleptic drug with sedative and antiemetic effects, which is used mainly as a tranquilizer in veterinary medicine. It is used mainly in pigs and elephants. [1] More rarely it may be used in humans as an antipsychotic drug, but this is uncommon. Use in horses is avoided as adverse reactions may occur.

Azaperone acts primarily as a dopamine antagonist but also has some antihistaminic and anticholinergic properties as seen with similar drugs such as haloperidol. Azaperone may cause hypotension and while it has minimal effects on respiration in pigs, high doses in humans can cause respiratory depression which may be why it is rarely used in humans.

The most common use for azaperone is in relatively small doses to reduce aggression in farmed pigs, either to stop them fighting or to encourage sows to accept piglets. Higher doses are used for anesthesia in combination with other drugs such as xylazine, tiletamine and zolazepam. Azaperone is also used in combination with strong narcotics such as etorphine or carfentanil for tranquilizing large animals such as elephants.