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Home / Equine Research Bank / Br J Pharmacol / Effects of azaperone on cardiovascular and respiratory funct...
British journal of pharmacology1976; 56(3); 263-269; doi: 10.1111/j.1476-5381.1976.tb07637.x

Effects of azaperone on cardiovascular and respiratory functions in the horse.

Abstract: 1 The butyrophenone tranquilizer, azaperone, was administered intramuscularly, at dose levels of 0.4 and 0.8 mg/kg, to ponies and its effects on cardiovascular and respiratory functions assessed. 2 Arterial blood pH, CO2 tension (PaCO2) and O2 tension (PaO2) remained relatively constant throughout the course of action of azaperone. 3 Azaperone did not modify plasma protein concentration but venous blood packed cell volume and haemoglobin concentration were reduced by 5 to 10% for at least 4 hours. These changes were probably caused by uptake of erythrocytes into the splenic reservoir. 4 Small increases in heart rate occurred for up to 60 min after administration of the drug, and this was followed by a slight bradycardia in some ponies. 5 Azaperone reduced mean arterial blood pressure (MAP) for at least 4 h, by which time its ataractic action was generally no longer apparent. The hypotension was caused, during the early phase of action at least, by a reduction in peripheral resistance, since cardiac output was increased slightly 20 min after its administration. Possible mechanisms underlying the cardiovascular changes are discussed. 6 In spite of reductions in arterial blood O2 content and MAP produced by azaperone, it is likely that tissue oxygenation was adequate, since arterial blood lactate concentrations were not increased.
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Publication Date: 1976-03-01 PubMed ID: 1260170PubMed Central: PMC1666940DOI: 10.1111/j.1476-5381.1976.tb07637.xGoogle Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research article explores the impact of the tranquilizer azaperone on cardiovascular and respiratory functions in ponies when administered at different dosages. The findings suggest that while the drug affects heart rate, blood pressure, cell volume and hemoglobin concentration, it does not significantly alter blood pH, carbon dioxide or oxygen levels, suggesting that overall tissue oxygenation is not compromised when azaperone is administered.

Overview of Experiments

  • The researchers administered the butyrophenone tranquilizer, azaperone, intramuscularly at doses of 0.4 and 0.8 mg/kg to ponies. They then assessed the effects of the medication on the cardiovascular and respiratory functions of the animals.

Findings and Probable Causes

  • Arterial blood pH, CO2 tension (PaCO2), and O2 tension (PaO2) remained relatively constant throughout the action of azaperone, indicating that azaperone does not significantly influence these parameters.
  • While azaperone did not alter the plasma protein concentration, it did lead to 5 to 10% reduction in venous blood packed cell volume and haemoglobin concentration for a minimum of four hours. These changes could be a result of the absorption of erythrocytes into the spleen’s reservoir.
  • Administering azaperone resulted in slight increases in heart rate for up to an hour, which was then followed by a decrease in heart rate in a few cases.
  • The tranquilizer also caused a drop in mean arterial blood pressure for at least four hours. The drop was primarily due to an early phase reduction in peripheral resistance, which led to a slight increase in cardiac output 20 minutes post-administration.

Implications and Conclusions

  • Although azaperone led to reductions in arterial blood oxygen content and mean arterial blood pressure, it’s suggested that tissue oxygenation likely remained sufficient, as there wasn’t an increase in arterial blood lactate concentrations. Tissue oxygenation is usually assessed based on blood lactate levels, as an increase in lactate concentration could indicate reduced tissue oxygenation. This suggests that the drop in heart rate and blood pressure do not significantly compromise oxygen delivery to tissues.
  • The research also discusses potential mechanisms driving the cardiovascular changes observed, though the mechanisms are not detailed in the abstract.

Cite This Article

APA
Lees P, Serrano L. (1976). Effects of azaperone on cardiovascular and respiratory functions in the horse. Br J Pharmacol, 56(3), 263-269. https://doi.org/10.1111/j.1476-5381.1976.tb07637.x

Publication

British journal of pharmacology
ISSN: 0007-1188
NlmUniqueID: 7502536
Country: England
Language: English
Volume: 56
Issue: 3
Pages: 263-269

Researcher Affiliations

Lees, P
    Serrano, L

      MeSH Terms

      • Animals
      • Azaperone / pharmacology
      • Blood Proteins / analysis
      • Blood Sedimentation
      • Butyrophenones / pharmacology
      • Carbon Dioxide / blood
      • Cardiac Output / drug effects
      • Female
      • Heart Rate / drug effects
      • Hemodynamics / drug effects
      • Hemoglobins / analysis
      • Horses
      • Lactates / blood
      • Male
      • Oxygen Consumption / drug effects
      • Pyruvates / blood
      • Time Factors
      • Tranquilizing Agents / pharmacology
      • Vascular Resistance / drug effects

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      This article includes 16 references
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      Citations

      This article has been cited 6 times.
      1. Gaudio E, Laubscher LL, Meyer LCR, Hoffman LC, Raath JP, Pfitzer S. Evaluation of two different etorphine doses combined with azaperone in blesbok (Damaliscus pygargus phillipsi) immobilisation. J S Afr Vet Assoc 2021 Aug 24;92(0):e1-e8.
        doi: 10.4102/jsava.v92i0.2161pubmed: 34476958google scholar: lookup
      2. Morra S, Pitisci L, Su F, Hossein A, Rabineau J, Racape J, Gorlier D, Herpain A, Migeotte PF, Creteur J, van de Borne P. Quantification of Cardiac Kinetic Energy and Its Changes During Transmural Myocardial Infarction Assessed by Multi-Dimensional Seismocardiography. Front Cardiovasc Med 2021;8:603319.
        doi: 10.3389/fcvm.2021.603319pubmed: 33763456google scholar: lookup
      3. Malinowski CM, Cameron AI, Burnside WM, West SE, Nunamaker EA. Butorphanol-Azaperone-Medetomidine for the Immobilization of Rhesus Macaques (Macaca mulatta). J Am Assoc Lab Anim Sci 2019 May 1;58(3):346-355.
        doi: 10.30802/AALAS-JAALAS-18-000088pubmed: 30935442google scholar: lookup
      4. Izwan A, Snelling EP, Seymour RS, Meyer LCR, Fuller A, Haw A, Mitchell D, Farrell AP, Costello MA, Maloney SK. Ameliorating the adverse cardiorespiratory effects of chemical immobilization by inducing general anaesthesia in sheep and goats: implications for physiological studies of large wild mammals. J Comp Physiol B 2018 Nov;188(6):991-1003.
        doi: 10.1007/s00360-018-1184-zpubmed: 30232543google scholar: lookup
      5. Carmona JU, Giraldo CE, Aristizabal W, García A, Vallejo LG. Evaluation of the effects of the sedation with azaperone/acepromazine and immobilization with guaiphenesin/thiopentone in mules. Vet Res Commun 2007 Feb;31(2):125-32.
        doi: 10.1007/s11259-006-3394-1pubmed: 17186408google scholar: lookup
      6. De Benedictis GM, Baggio A, Pesaro S, Magnone W, Miani G, Andolfatto A, Bono L, Zanusso F. Evaluation of a detomidine-ketamine-azaperone combination for the chemical immobilization of fallow deer (Dama dama). Front Vet Sci 2025;12:1718243.
        doi: 10.3389/fvets.2025.1718243pubmed: 41321571google scholar: lookup
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