Pharmacokinetics and pharmacodynamics of butorphanol in llamas after intravenous and intramuscular administration

PURPOSE:To assess the hemodynamic changes and bispectral index (BIS) following administration of a continuous rate infusion (CRI) of butorphanol in isoflurane-anesthetized calves. METHODS:Eight calves weighing 110 ± 12 kg were included in the study. Anesthesia was induced with 5% isoflurane in O 2 delivered via face mask and maintained with end-tidal concentration of 1.4%. IPPV was set to a peak inspiratory airway pressure of 15 cmH 2 O and respiratory rate of six breaths minute -1 . Forty minutes after the start of anesthetic maintenance, 0.1 mg kg -1 butorphanol was administered intravenously, followed by a CRI of 20 µg kg -1 minute -1 . Hemodynamic variables and BIS were recorded before butorphanol administration (T0), and at 10, 20, 40 and 80 minutes following the CRI. Anesthesia was discontinued after the last recording and the calves were allowed to recover. The time to sternal recumbency (SRE) and standing (ST) were evaluated. RESULTS:There were no significant differences between the moments in all hemodynamic variables and BIS. The time to SRE and ST was 9 ± 5 and 14 ± 7 minutes, respectively. CONCLUSION:The continuous rate infusion did not produce clinically relevant changes in hemodynamic or bispectral index values compared to baseline in mechanically ventilated and unstimulated calves anesthetized at 1.4% isoflurane.

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“…The use of an IV dose of 0.1 mg kg -1 of butorphanol was based on previous studies using the same opioid in ruminants 14,18 .…”

Section: Discussionmentioning

confidence: 99%

Effects of continuous rate infusion of butorphanol in isoflurane-anesthetized calves

Araújo

Albuquerque²,

Deschk

et al. 2014

Acta Cir. Bras.

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“…41 The lower mean C max concentration compared with the therapeutic concentrations of horses (20 ng/ml), goats (9 ng/ml), llamas (>9.2 ng/ml), dogs (9 ng/ml), and cats (45 ng/ml) with clinically subjective therapeutic effect indicates that elephants may be very sensitive to this opioid. 6,7,41,44,47 This sensitivity could be due to the concentration at the receptor sites or differences in the distribution of these sites. Analgesia is determined by the concentration at the receptor site, which does not necessarily correlate with the plasma concentration.…”

Section: Discussionmentioning

confidence: 99%

“…An emphasis was placed on those metabolites reported previously in human and domestic species metabolite determination, including hydroxybutorphanol and norbutorphanol. 6,13,14,31,45,48 The spectra were compared using the LC–MS software set to scan for metabolites while detecting butorphanol, and the metabolites were not found to cross-react with unchanged butorphanol.…”

Section: Methodsmentioning

confidence: 99%

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Pharmacokinetics and Intramuscular Bioavailability of a Single Dose of Butorphanol in Asian Elephants (Elephas maximus)

Tana

Isaza²,

Koch³

et al. 2010

Journal of Zoo and Wildlife Medicine

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Captive Asian elephants (Elephas maximus) are susceptible to lameness resulting from foot and joint pain, including chronic arthritis. In the past, opioid analgesics, such as butorphanol, have been used clinically for pain management. However, dosages used in treating elephants were often extrapolated from data in horses, with no pharmacokinetic information on the specific agents used in elephant species. In this pharmacokinetic study, six adult captive Asian elephants (5 female, 1 male castrate) were administered a 0.015 mg/kg dose of butorphanol by both i.v. and i.m. routes. A complete crossover design was used with a 3-wk washout period between treatments. Serial blood samples were collected immediately prior to butorphanol administration and at 5, 10, 20, and 40 min and 1, 1.5, 2, 3, 4, 5, 6, 8, 10, and 24 h after administration. The butorphanol analysis was performed using a validated liquid chromatography–mass spectrophotometric assay with a limit of quantitation of 0.025 ng/ml. The mean Cmax after i.m. administration was 7.9 ng/ml, with a corresponding Tmax of 40 min and t½ of 7.1 h. After i.v. administration, the mean Vdss was 1.4 L/kg and the mean Clp was 0.26 L/kg/h. Mean i.m. bioavailability was 37%. The results indicate that butorphanol used at 0.015 mg/kg i.m. or i.v. could be useful in elephants when given for pain control.

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“…[1] In mammals, butorphanol has agonist activity at κ-receptors while having partial agonist and antagonist activity at µ-receptor sites. [6,7] Several high-performance liquid chromatography (HPLC) methods have been developed for the extraction of butorphanol from plasma [1,2,[8][9][10][11][12][13][14] ; however, some use expensive solid-phase extraction (SPE) columns [1,[8][9][10] or time-consuming multistep, liquid-liquid extractions. [2,11,12] Mass spectrometry has been used in conjunction with both liquid and gas chromatography; however, these instruments are costly and may not be available in some laboratories.…”

Section: Introductionmentioning

confidence: 99%

Determination of Butorphanol Using High Performance Liquid Chromatography in Small Volume Plasma Samples

Yarbrough

Greenacre

Cox

2014

Journal of Liquid Chromatography & Related Technologies

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A high-performance liquid chromatography (HPLC) method has been developed and validated for the determination of butorphanol in bearded dragon plasma. Following a liquid extraction using ethyl acetate and hexane, samples were separated by gradient reverse phase HPLC on a Symmetry C 18 column and quantified using fluorescence detection at an excitation of 200 nm and an emission of 325 nm. The mobile phase was a mixture of 0.05 M ammonium acetate (pH, 4.1) and acetonitrile, with a flow rate of 1.3 mL/min. A linear curve was produced over the concentration range of 2.5 to 1500 ng/mL. Intra-and inter-assay variability for butorphanol were less than 10% and the average recovery was 90%. The new assay quantifies therapeutic levels of butorphanol in 100 µL samples from pharmacokinetic studies conducted at this institution.

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Pharmacokinetics and pharmacodynamics of butorphanol in llamas after intravenous and intramuscular administration

Cited by 30 publications

References 17 publications

Effects of continuous rate infusion of butorphanol in isoflurane-anesthetized calves

Effects of continuous rate infusion of butorphanol in isoflurane-anesthetized calves

Pharmacokinetics and Intramuscular Bioavailability of a Single Dose of Butorphanol in Asian Elephants (Elephas maximus)

Determination of Butorphanol Using High Performance Liquid Chromatography in Small Volume Plasma Samples

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