Influence of general anaesthesia on the pharmacokinetics of intravenous fentanyl and its primary metabolite in horses

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Reasons for performing study: In order to evaluate its potential as an adjunct to inhalant anaesthesia in horses, the pharmacokinetics of fentanyl must first be determined. Objectives: To describe the pharmacokinetics of fentanyl and its metabolite, N-[1-(2-phenethyl-4-piperidinyl)maloanilinic acid (PMA), after i.v. administration of a single dose to horses that were awake in Treatment 1 and anaesthetised with isoflurane in Treatment 2. Methods: A balanced crossover design was used (n = 4/group). During Treatment 1, horses received a single dose of fentanyl (4 μg/kg bwt, i.v.) and during Treatment 2, they were anaesthetised with isoflurane and maintained at 1.2 x minimum alveolar anaesthetic concentration. After a 30 min equilibration period, a single dose of fentanyl (4 μg/kg bwt, i.v.) was administered to each horse. Plasma fentanyl and PMA concentrations were measured at various time points using liquid chromatography-mass spectrometry. Results: Anaesthesia with isoflurane significantly decreased mean fentanyl clearance (P<0.05). The fentanyl elimination half-life, in awake and anaesthetised horses, was 1 h and volume of distribution at steady state was 0.37 and 0.26 l/kg bwt, respectively. Anaesthesia with isoflurane also significantly decreased PMA apparent clearance and volume of distribution. The elimination half-life of PMA was 2 and 1.5 h in awake and anaesthetised horses, respectively. Conclusions and potential relevance: Pharmacokinetics of fentanyl and PMA in horses were substantially altered in horses anaesthetised with isoflurane. These pharmacokinetic parameters provide information necessary for determination of suitable fentanyl loading and infusion doses in awake and isoflurane-anaesthetised horses.

Original languageEnglish (US)
Pages (from-to)54-58
Number of pages5
JournalEquine Veterinary Journal
Volume39
Issue number1
DOIs
StatePublished - Jan 2007

Fingerprint

fentanyl
Fentanyl
General Anesthesia
pharmacokinetics
Horses
anesthesia
Pharmacokinetics
Isoflurane
isoflurane
metabolites
horses
Anesthesia
dosage
half life
Half-Life
Liquid Chromatography
anesthetics
Cross-Over Studies
liquid chromatography
Anesthetics

Keywords

  • Anaesthesia
  • Analgesia
  • Horse
  • Isoflurane
  • Opioids
  • Pharmacokinetics

ASJC Scopus subject areas

  • veterinary(all)

Cite this

@article{c7743bcac6714d21b4db90bbe333785e,
title = "Influence of general anaesthesia on the pharmacokinetics of intravenous fentanyl and its primary metabolite in horses",
abstract = "Reasons for performing study: In order to evaluate its potential as an adjunct to inhalant anaesthesia in horses, the pharmacokinetics of fentanyl must first be determined. Objectives: To describe the pharmacokinetics of fentanyl and its metabolite, N-[1-(2-phenethyl-4-piperidinyl)maloanilinic acid (PMA), after i.v. administration of a single dose to horses that were awake in Treatment 1 and anaesthetised with isoflurane in Treatment 2. Methods: A balanced crossover design was used (n = 4/group). During Treatment 1, horses received a single dose of fentanyl (4 μg/kg bwt, i.v.) and during Treatment 2, they were anaesthetised with isoflurane and maintained at 1.2 x minimum alveolar anaesthetic concentration. After a 30 min equilibration period, a single dose of fentanyl (4 μg/kg bwt, i.v.) was administered to each horse. Plasma fentanyl and PMA concentrations were measured at various time points using liquid chromatography-mass spectrometry. Results: Anaesthesia with isoflurane significantly decreased mean fentanyl clearance (P<0.05). The fentanyl elimination half-life, in awake and anaesthetised horses, was 1 h and volume of distribution at steady state was 0.37 and 0.26 l/kg bwt, respectively. Anaesthesia with isoflurane also significantly decreased PMA apparent clearance and volume of distribution. The elimination half-life of PMA was 2 and 1.5 h in awake and anaesthetised horses, respectively. Conclusions and potential relevance: Pharmacokinetics of fentanyl and PMA in horses were substantially altered in horses anaesthetised with isoflurane. These pharmacokinetic parameters provide information necessary for determination of suitable fentanyl loading and infusion doses in awake and isoflurane-anaesthetised horses.",
keywords = "Anaesthesia, Analgesia, Horse, Isoflurane, Opioids, Pharmacokinetics",
author = "Thomasy, {Sara M} and Mama, {K. R.} and Grimsrud, {Kristin N} and Eugene Steffey and Stanley, {Scott D}",
year = "2007",
month = "1",
doi = "10.2746/042516407X153011",
language = "English (US)",
volume = "39",
pages = "54--58",
journal = "Equine veterinary journal. Supplement",
issn = "2042-3306",
publisher = "British Equine Veterinary Association",
number = "1",

}

TY - JOUR

T1 - Influence of general anaesthesia on the pharmacokinetics of intravenous fentanyl and its primary metabolite in horses

AU - Thomasy, Sara M

AU - Mama, K. R.

AU - Grimsrud, Kristin N

AU - Steffey, Eugene

AU - Stanley, Scott D

PY - 2007/1

Y1 - 2007/1

N2 - Reasons for performing study: In order to evaluate its potential as an adjunct to inhalant anaesthesia in horses, the pharmacokinetics of fentanyl must first be determined. Objectives: To describe the pharmacokinetics of fentanyl and its metabolite, N-[1-(2-phenethyl-4-piperidinyl)maloanilinic acid (PMA), after i.v. administration of a single dose to horses that were awake in Treatment 1 and anaesthetised with isoflurane in Treatment 2. Methods: A balanced crossover design was used (n = 4/group). During Treatment 1, horses received a single dose of fentanyl (4 μg/kg bwt, i.v.) and during Treatment 2, they were anaesthetised with isoflurane and maintained at 1.2 x minimum alveolar anaesthetic concentration. After a 30 min equilibration period, a single dose of fentanyl (4 μg/kg bwt, i.v.) was administered to each horse. Plasma fentanyl and PMA concentrations were measured at various time points using liquid chromatography-mass spectrometry. Results: Anaesthesia with isoflurane significantly decreased mean fentanyl clearance (P<0.05). The fentanyl elimination half-life, in awake and anaesthetised horses, was 1 h and volume of distribution at steady state was 0.37 and 0.26 l/kg bwt, respectively. Anaesthesia with isoflurane also significantly decreased PMA apparent clearance and volume of distribution. The elimination half-life of PMA was 2 and 1.5 h in awake and anaesthetised horses, respectively. Conclusions and potential relevance: Pharmacokinetics of fentanyl and PMA in horses were substantially altered in horses anaesthetised with isoflurane. These pharmacokinetic parameters provide information necessary for determination of suitable fentanyl loading and infusion doses in awake and isoflurane-anaesthetised horses.

AB - Reasons for performing study: In order to evaluate its potential as an adjunct to inhalant anaesthesia in horses, the pharmacokinetics of fentanyl must first be determined. Objectives: To describe the pharmacokinetics of fentanyl and its metabolite, N-[1-(2-phenethyl-4-piperidinyl)maloanilinic acid (PMA), after i.v. administration of a single dose to horses that were awake in Treatment 1 and anaesthetised with isoflurane in Treatment 2. Methods: A balanced crossover design was used (n = 4/group). During Treatment 1, horses received a single dose of fentanyl (4 μg/kg bwt, i.v.) and during Treatment 2, they were anaesthetised with isoflurane and maintained at 1.2 x minimum alveolar anaesthetic concentration. After a 30 min equilibration period, a single dose of fentanyl (4 μg/kg bwt, i.v.) was administered to each horse. Plasma fentanyl and PMA concentrations were measured at various time points using liquid chromatography-mass spectrometry. Results: Anaesthesia with isoflurane significantly decreased mean fentanyl clearance (P<0.05). The fentanyl elimination half-life, in awake and anaesthetised horses, was 1 h and volume of distribution at steady state was 0.37 and 0.26 l/kg bwt, respectively. Anaesthesia with isoflurane also significantly decreased PMA apparent clearance and volume of distribution. The elimination half-life of PMA was 2 and 1.5 h in awake and anaesthetised horses, respectively. Conclusions and potential relevance: Pharmacokinetics of fentanyl and PMA in horses were substantially altered in horses anaesthetised with isoflurane. These pharmacokinetic parameters provide information necessary for determination of suitable fentanyl loading and infusion doses in awake and isoflurane-anaesthetised horses.

KW - Anaesthesia

KW - Analgesia

KW - Horse

KW - Isoflurane

KW - Opioids

KW - Pharmacokinetics

UR - http://www.scopus.com/inward/record.url?scp=33846010141&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33846010141&partnerID=8YFLogxK

U2 - 10.2746/042516407X153011

DO - 10.2746/042516407X153011

M3 - Article

C2 - 17228596

AN - SCOPUS:33846010141

VL - 39

SP - 54

EP - 58

JO - Equine veterinary journal. Supplement

JF - Equine veterinary journal. Supplement

SN - 2042-3306

IS - 1

ER -