Antinociceptive effects of levomethadone in standing horses sedated with romifidine.

Studer, Nicole; Dìez Bernal, Sabina; Thormann, Wolfgang; Levionnois, Olivier; Spadavecchia, Claudia (2021). Antinociceptive effects of levomethadone in standing horses sedated with romifidine. Veterinary anaesthesia and analgesia, 48(3), pp. 451-460. Elsevier 10.1016/j.vaa.2020.08.011

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OBJECTIVE

To evaluate the antinociceptive effect of a bolus of intravenous levomethadone administered to horses during romifidine constant rate infusion (CRI).

STUDY DESIGN

Prospective, randomized, masked, crossover experimental study.

ANIMALS

A group of eight adult Warmblood horses (seven geldings, one mare) aged 6.6 ± 4.4 years, weighing 548 ± 52 kg [mean ± standard deviation (SD)].

METHODS

Levomethadone 0.1 mg kg-1 or an equivalent volume of saline (control) was administered intravenously to standing horses 60 minutes after starting a romifidine CRI. Blood samples to quantify romifidine and levomethadone plasma concentrations by capillary electrophoresis were collected up to 150 minutes after levomethadone administration. The nociceptive withdrawal reflex threshold (NWRT) was determined continuously using an automated threshold tracking device. Sedation and cardiopulmonary variables were assessed at regular intervals. A pharmacokinetic-pharmacodynamic (PK-PD) model was elaborated. Data are presented as mean ± SD or median (interquartile range, 25%-75%) where appropriate. Differences between groups were considered statistically significant for p < 0.05.

RESULTS

Horses exhibited higher NWRTs after levomethadone administration than after saline (123 ± 9% versus 101 ± 9% relative to baseline, p < 0.05). The PK-PD model identified a contribution of levomethadone to the NWRT increase. Effect size was variable among individuals. No adverse reactions to levomethadone administration were observed. A slight effect of levomethadone on sedation scores was evident for the 60 minutes following its administration.

CONCLUSIONS AND CLINICAL RELEVANCE

A single injection of levomethadone has the potential to increase the NWRT during romifidine CRI in horses and can be administered in combination with α2-adrencoceptor agonists to enhance antinociception in horses. However, individual variation is marked.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > DKV - Anaesthesiology
04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases

UniBE Contributor:

Studer, Nicole; Dìez Bernal, Sabina; Thormann, Wolfgang; Levionnois, Olivier and Spadavecchia, Claudia

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

1467-2995

Publisher:

Elsevier

Language:

English

Submitter:

Wolfgang Thormann

Date Deposited:

23 Dec 2021 11:24

Last Modified:

23 Dec 2021 11:24

Publisher DOI:

10.1016/j.vaa.2020.08.011

PubMed ID:

33685821

Uncontrolled Keywords:

PK-PD antinociception horses levomethadone nociceptive withdrawal reflex

BORIS DOI:

10.48350/162993

URI:

https://boris.unibe.ch/id/eprint/162993

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