Morphine with or without Acepromazine in Horses: A Kinematic Evaluation.
Authors: López-Sanromán F Javier, Montes Freilich G, Gómez-Cisneros D, Izquierdo-Moreno J, Varela Del Arco M, Manso-Díaz G
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Morphine with or without Acepromazine in Horses – A Kinematic Evaluation López-Sanromán and colleagues investigated whether combining acepromazine with morphine could mitigate unwanted locomotor effects, since opioids alone can cause CNS excitation in equines whilst acepromazine typically produces sedation. Using three-dimensional accelerometry in six horses receiving saline, morphine alone (0.2 mg/kg), acepromazine alone (0.02 mg/kg), or both drugs together, the researchers tracked eight kinematic variables—including stride regularity, coordination, and energetic parameters—alongside ground-to-lip distance as a tranquilisation marker across a three-hour post-injection period. The combination treatment revealed a counterbalancing effect: whilst morphine and acepromazine each altered the walking pattern when administered separately, their co-administration appeared to neutralise many of these gait disturbances, with significantly fewer alterations observed across most measured variables. For practitioners, this finding suggests that concurrent acepromazine administration may allow safer use of morphine in horses by preserving more normal locomotor mechanics whilst still providing analgesia and preventing opioid-induced excitement—a meaningful consideration for perioperative sedation or pain management protocols where gait stability is clinically important.
Read the full abstract on PubMed
Practical Takeaways
- •When administering morphine to horses, combining it with acepromazine can reduce unwanted locomotor effects and CNS excitation, making opioid use safer in clinical practice
- •Three-dimensional accelerometry can objectively quantify gait changes induced by sedative and analgesic combinations, helping optimize drug protocols
- •This combination approach may expand safe use of opioids in equine anaesthesia and analgesia protocols
Key Findings
- •Co-administration of acepromazine (0.02 mg/kg) and morphine (0.2 mg/kg) produced significant counteraction of gait pattern alterations compared to either drug alone
- •Significant interactions observed in stride kinematics, coordination, and energetic parameters across all treatment groups
- •Combined acepromazine-morphine treatment minimized CNS excitation while maintaining safe opioid administration
- •Ground-to-lip distance (tranquilization marker) showed no significant differences between treatments