Guaifenesin: cardiopulmonary effects and plasma concentrations in horses.
Abstract: We determined the cardiopulmonary changes in horses given guaifenesin alone and in the same horses given xylazine (IV) immediately before administration of guaifenesin. In addition, plasma guaifenesin concentrations were determined in horses and 2 pregnant mares and compared with previously published values in ponies. The dose of guaifenesin necessary to produce lateral recumbency in adult horses was 134 +/- 34 mg/kg (mean +/- SD). The administration of guaifenesin caused insignificant (P less than 0.05) changes in heart rate, respiratory rate, right atrial pressure, pulmonary arterial pressure, and cardiac output. Systolic, diastolic, and mean arterial blood pressures were significantly (P less than 0.05) decreased. Arterial partial pressure of oxygen (PaO2) was transiently, but significantly (P less than 0.05), reduced. The administration of xylazine (IV) to the horses before they were given guaifenesin reduced the dose of guaifenesin necessary to produce lateral recumbency to 88 +/- 10 mg/kg. In these horses, there were significant transient decreases in heart rate, respiratory rate, cardiac output, and PaO2. Central venous pressure remained significantly (P less than 0.05) increased, whereas systolic, diastolic, and mean arterial blood pressures were significantly (P less than 0.05) decreased at all times. In horses given guaifenesin alone, plasma concentrations at the time of lateral recumbency were 313 +/- 108 microgram/ml, and in those given xylazine-guaifenesin, the concentrations of the drug were 277 +/- 83 microgram/ml. Neonatal concentrations of guaifenesin were approximately 30% of that of the mare immediately after delivery, indicating that significant amounts of guaifenesin cross the placental barrier in the mare.
Publication Date: 1980-11-01 PubMed ID: 7212404
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- Comparative Study
- Journal Article
Summary
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The research analyzed the cardiorespiratory effects of guaifenesin administration in horses, as well as the impact of a preexisting xylazine dosage. Also, they studied guaifenesin plasma concentrations in horses and pregnant mares, revealing that this drug can cross the placental barrier.
Dosage and Administration
- The researchers administered two sets of drugs to the horses for this study – guaifenesin alone and xylazine followed by guaifenesin. Subsequently, they measured the effects these substances had on the horses’ cardiopulmonary functions.
- The dose of guaifenesin that was necessary to induce lateral recumbency or side-lying position in adult horses was found to be approximately 134 +/- 34 mg/kg. This dosage produced insignificant changes in several parameters like heart rate, respiratory rate, right atrial pressure, pulmonary arterial pressure, and cardiac output.
- However, pre-administration of xylazine to the horses significantly reduced the dose of guaifenesin required to bring about the same effect to 88 +/- 10 mg/kg. This combination also led to significant momentary decreases in heart rate, respiratory rate, cardiac output, and oxygen partial pressure, while significantly increasing the central venous pressure.
Plasma Concentrations and Cross-Placental Transfer
- Simultaneously, the researchers measured the plasma concentrations of guaifenesin at the time of lateral recumbency in both groups of horses.
- In horses given only guaifenesin, the concentrations of the drug were found to be 313 +/- 108 microgram/ml, and in those being administered xylazine followed by guaifenesin, the concentrations were measured to be 277 +/- 83 microgram/ml.
- The study also evaluated the transfer of guaifenesin across the placental barrier in pregnant mares. The results showed that around 30% of the mare’s guaifenesin concentration was found in the neonate immediately after birth, signaling that guaifenesin does cross the placental barrier in measurable amounts.
Cite This Article
APA
Hubbell JA, Muir WW, Sams RA.
(1980).
Guaifenesin: cardiopulmonary effects and plasma concentrations in horses.
Am J Vet Res, 41(11), 1751-1755.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Animals, Newborn / blood
- Blood Pressure / drug effects
- Cardiac Output / drug effects
- Cardiovascular System / drug effects
- Female
- Fetal Blood / analysis
- Guaifenesin / blood
- Guaifenesin / pharmacology
- Heart Rate / drug effects
- Horses / blood
- Horses / physiology
- Male
- Pregnancy
- Pulmonary Artery / drug effects
- Respiration / drug effects
- Xylazine / pharmacology
Citations
This article has been cited 3 times.- Tokushige H, Araki M, Kusano K, Arima D, Ito H, Yamazaki Y, Urayama S, Kambayashi Y, Tateno O, Ohta M. A retrospective comparison of induction with thiopental/guaifenesin and propofol/ketamine in Thoroughbred racehorses anesthetized with sevoflurane and medetomidine during arthroscopic surgery.. J Equine Sci 2019 Jul;30(2):25-31.
- Olson ME, McCabe K, Walker RL. Guaifenesin alone or in combination with ketamine or sodium pentobarbital as an anesthetic in rabbits.. Can J Vet Res 1987 Jul;51(3):383-6.
- Gasthuys F, Vandamme R, De Moor A, De Meurichy W. Haemodynamic, metabolic and physical responses to a neuroleptanalgesic-glyceryl guaiacolate combination in the horse.. Vet Res Commun 1989;13(2):113-26.
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