The pharmacology of furosemide in the horse. V. Pharmacokinetics and blood levels of furosemide after intravenous administration

S. Chay, W. E. Woods, K. Rowse, T. E. Nugent, J. W. Blake, T. Tobin

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Studies were undertaken to determine blood levels of furosemide in horses after 0.5- and 1.0-mg/kg doses administered iv. Analyses indicated that the pharmacokinetic parameters were dose independent and best described by a three-compartment open model. The α, β, and γ-phase half-lives of 5.6, 22.3, and 158.5 min, respectively, were observed after the 0.5-mg/kg dose. Similarly, the respective half-lives after the 1.0 mg/kg dose were 5.8, 24.1, and 177.2 min. After a 0.5-mg/kg dose of furosemide, population frequency distributions were evaluated at 1 hr and 4 hr post-drug administration. At 1 hr after dosing, the blood levels of furosemide in 30 horses were normally distributed. The mean plasma level was 97.9 ng/ml with a range of 41.9 ng/ml to 155.8 ng/ml and a SD of 25.0 ng/ml. Analysis of blood levels of furosemide in 47 horses at 4 hr after drug administration indicated that the population distribution was better fit by a normal curve after log transformation of the values. The mean plasma level at 4 hr post-dosing was 9.6 ng/ml with a range of 4.0 ng/ml to 19.4 ng/ml and a SD of 3.1 ng/ml. Based on this population distribution of the plasma levels, the probability of finding furosemide, population frequency distributions were evaluated at 1 hr and 4 hr post-drug administration. At 1 hr after dosing, the blood levels of furosemide in 30 horses were normally distributed. The mean plasma level was 97.9 ng/ml with a range of 41.9 ng/ml to 155.8 ng/ml and a SD of 25.0 ng/ml. Analyses of blood levels of furosemide in 47 horses at 4 hr after drug administration indicated that the population distribution was better fit by a normal curve after log transformation of the values. The mean plasma level at 4 hr post-dosing was 9.6 ng/ml with a range of 4.0 ng/ml to 19.4 ng/ml and a SD of 3.1 ng/ml. Based on this population distribution of the plasma levels, the probability of finding furosemide plasma concentrations above 24.6 ng/ml at 4 hr after anti-epistaxis dose was estimated at less than 1 in 1000.

Original languageEnglish
Pages (from-to)226-231
Number of pages6
JournalDrug Metabolism and Disposition
Volume11
Issue number3
StatePublished - 1983

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science

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