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In some countries, this medicine may only be approved for veterinary use.



CAS registry number (Chemical Abstracts Service)


Chemical Formula


Molecular Weight


Therapeutic Categories

Sedative agent

Neuroleptic agent

Agent for premedication

Chemical Name

4'-fluoro-4-[4-(2-pyridyl)-1-piperazinyl]butyrophenone (WHO)

Foreign Names

  • Azaperonum (Latin)
  • Azaperon (German)
  • Azapérone (French)
  • Azaperona (Spanish)

Generic Names

  • Azaperone (OS: BAN, USAN)
  • Azapérone (OS: DCF)
  • 5-23-03-00041 (Beilstein) (IS)
  • BRN 0565491 (IS)
  • R 1929 (IS)
  • UNII-19BV78AK7W (IS)
  • Azaperon für Tiere (PH: Ph. Eur. 9)
  • Azaperone (PH: BP vet. 2018, USP 41)
  • Azaperone for veterinary use (PH: Ph. Eur. 9)
  • Azapérone pour usage vétérinaire (PH: Ph. Eur. 9)
  • Azaperonum ad usum veterinarium (PH: Ph. Eur. 9)

Brand Names

  • Fentazin [veterinary use]
    Bayer New Zealand, New Zealand
  • Fentazin 5 [+ Fentanyl, + Xylazine] [veterinary use]
    Bayer New Zealand, New Zealand
  • Stresnil [veterinary use]
    Elanco, New Zealand; Elanco, South Africa; Elanco Animal Health, Ireland; Elanco Animal Health, United States; Elanco Deutschland GmbH, Germany; Elanco Tiergesundheit AG, Switzerland; Eli Lilly Benelux, Belgium; Janssen-Cilag, Italy; Janssen-Cilag, Poland; Lilly, United Kingdom; Lilly Vet, France
  • Stresnil 40 mg/ml für Schweine [veterinary use]
    Elanco Animal Health, Austria
  • Stresnil 40 mg/ml voor varkens [veterinary use]
    Lilly-Elanco, Netherlands
  • Stresnil for Pigs [veterinary use]
    Elanco Animal Health, Australia


BANBritish Approved Name
DCFDénomination Commune Française
ISInofficial Synonym
OSOfficial Synonym
PHPharmacopoeia Name
Rec.INNRecommended International Nonproprietary Name (World Health Organization)
USANUnited States Adopted Name
WHOWorld Health Organization

Further information on drug naming conventions: International Nonproprietary Names.

Important Notice: The international database is in BETA release. This means it is still under development and may contain inaccuracies. It is not intended as a substitute for the expertise and judgement of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that the use of any medication in any country is safe, appropriate or effective for you. Consult with your healthcare professional before taking any medication.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.