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. 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.