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Small A, Fisher AD, Lee C, Colditz I. Analgesia for Sheep in Commercial Production: Where to Next? Animals (Basel) 2021; 11:ani11041127. [PMID: 33920025 PMCID: PMC8070992 DOI: 10.3390/ani11041127] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on industry to alleviate pain associated with husbandry practices, injury and illness. Although a number of analgesic solutions are now available for sheep, providing some amelioration of the acute pain responses, this review has highlighted a number of potential areas for further research. Abstract Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.
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Affiliation(s)
- Alison Small
- CSIRO Agriculture & Food, Locked Bag 1, Armidale, NSW 2350, Australia; (C.L.); (I.C.)
- Correspondence: ; Tel.: +61-2-6776-1435
| | - Andrew David Fisher
- Animal Welfare Science Centre, University of Melbourne, Parkville, VIC 3052, Australia;
| | - Caroline Lee
- CSIRO Agriculture & Food, Locked Bag 1, Armidale, NSW 2350, Australia; (C.L.); (I.C.)
| | - Ian Colditz
- CSIRO Agriculture & Food, Locked Bag 1, Armidale, NSW 2350, Australia; (C.L.); (I.C.)
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Abstract
IMPORTANCE OF THE FIELD Systemic toxicity, usually from overdose or intravascular dose, is feared because it mainly affects the heart and brain, and may be acutely life-threatening. AREAS COVERED IN THIS REVIEW Pharmacological studies of local anesthetic toxicity have largely been reviewed primarily relating to the evaluation of ropivacaine and levobupivacaine during the past decade. This review/opinion focuses more on the principles and concepts underlying the main models used, from chemical pharmacological and pharmacokinetic perspectives. WHAT THE READER WILL GAIN Research models required to produce pivotal toxicity data are discussed. The potencies for neural blockade and systemic toxicity are associated across virtually all models, with some deviations through molecular stereochemistry. These models show that all local anesthetics can produce direct cardiovascular system toxicity and CNS excitotoxicity that may further affect the cardiovascular system response. Whereas the longer-acting local anesthetics are more likely to cause cardiac death by malignant arrhythmias, the shorter-acting agents are more likely to cause cardiac contraction failure. In most models, equi-anesthetic doses of ropivacaine and levobupivacaine are less likely to produce serious toxicity than bupivacaine. TAKE HOME MESSAGE Of the various models, this reviewer favors a whole-body large animal preparation because of the comprehensive data collection possible. The conscious sheep preparation has contributed more than any other, and may be regarded as the de facto 'standard' experimental model for concurrent study of local anesthetic toxicity ± pharmacokinetics, using experimental designs that can reproduce the toxicity seen in clinical accidents.
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Affiliation(s)
- Laurence E Mather
- The University of Sydney, Royal North Shore Hospital, Department of Anaesthesia & Pain Management, St Leonards, Sydney 2065, Australia.
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Copeland SE, Ladd LA, Gu XQ, Mather LE. The Effects of General Anesthesia on Whole Body and Regional Pharmacokinetics of Local Anesthetics at Toxic Doses. Anesth Analg 2008; 106:1440-9, table of contents. [DOI: 10.1213/ane.0b013e31816ba541] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wiedemann D, Mühlnickel B, Staroske E, Neumann W, Röse W. Ropivacaine plasma concentrations during 120-hour epidural infusion. Br J Anaesth 2000; 85:830-5. [PMID: 11732514 DOI: 10.1093/bja/85.6.830] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The pharmacokinetics of ropivacaine were evaluated during long-term continuous epidural analgesia (CEDA) for about 120 h. The total and free plasma concentrations of ropivacaine and the alpha1-acid glycoprotein (AAG) concentration were measured in 12 patients after total knee arthroplasty. The infusion rate was adjusted according to patients' analgesic needs or side effects. The mean (SD) rate of infusion of ropivacaine (Naropin 2 mg ml(-1)) was 14.6 (3.2) mg h(-1) on the day of surgery and was increased after surgery to 15.4 (4.4) mg h(-1) on days 1-5. This was equivalent to an absolute dose of 1786 (553) mg of ropivacaine over the entire infusion period. After an initial increase, the mean free ropivacaine plasma concentration nearly plateaued and than decreased slightly after approximately 70 h. The individual peak free plasma concentration was 0.096 (0.034) microg ml(-1). The highest individual free plasma concentration was 0.16 microg ml(-1). The individual peak total plasma concentration, 4.1 (1.2) microg ml(-1), was achieved after 67.7 (16.5) h, although the AAG concentration increased throughout the observation period. Our data support the safety and efficacy of long-term ropivacaine CEDA.
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Affiliation(s)
- D Wiedemann
- Department of Anaesthesiology and Critical Care Medicine, Otto von Guericke University, Magdeburg, Germany
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Sanada H, Asico LD, Shigetomi S, Tanaka K, Niimura S, Watanabe H, Goldstein DS, Felder RA. The effect of docarpamine, a dopamine pro-drug, on blood pressure and catecholamine levels in spontaneously hypertensive rats. Clin Exp Hypertens 2000; 22:419-29. [PMID: 10830753 DOI: 10.1081/ceh-100100081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We studied the effects of bolus intravenous injection of the dopamine prodrug, docarpamine (200 microg/kg), on mean arterial pressure (MAP) and heart rate (HR) in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHRs). In WKY rats (n=18), MAP and HR increased 5 min after docarpamine and then returned to baseline levels within 15 min. In contrast, in SHRs (n=15), MAP and HR gradually decreased, reaching a nadir 20 min after injection. Five min after docarpamine, plasma dopamine and 3,4-dihydroxy phenyl acetic (DOPAC) levels increased in both WKY rats (n=5) and SHRs (n=5). The docarpamine-induced changes in MAP and HR in both rat strains (n=5/strain) were blocked by the D1-like antagonist, SCH23390. alpha-Adrenergic (n=4) and vasopressin V1 (n=3) receptor blockade also abrogated the effects of docarpamine in WKY rats. We conclude that docarpamine differentially affects MAP and HR in WKY and SHRs. In SHRs, the depressor and bradycardiac effects of docarpamine are mediated by D1-like receptors. In WKY rats, the pressor and tachycardiac responses are caused by an interaction among D1-like, alpha-adrenergic, and V1 receptors.
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Affiliation(s)
- H Sanada
- Department of Pathology, The University of Virginia Health Sciences Center, Charlottesville, USA
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Santos AC, Arthur GR, Lehning EJ, Finster M. Comparative Pharmacokinetics of Ropivacaine and Bupivacaine in Nonpregnant and Pregnant Ewes. Anesth Analg 1997. [DOI: 10.1213/00000539-199707000-00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Santos AC, Arthur GR, Lehning EJ, Finster M. Comparative pharmacokinetics of ropivacaine and bupivacaine in nonpregnant and pregnant ewes. Anesth Analg 1997; 85:87-93. [PMID: 9212128 DOI: 10.1097/00000539-199707000-00016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We determined the pharmacokinetics and protein binding of ropivacaine and bupivacaine after intravenous administration to nonpregnant and pregnant sheep. All animals were in good condition throughout the study. The highest mean total serum drug concentrations were found at the end of infusion. For both drugs, pregnancy was associated with lower volumes of distribution during the terminal phase of drug elimination (V(d)beta) and steady state (V(d)ss), as well as with a lower total body clearance (CL). The relationship between V(d)beta and CL was such that the elimination half-life (T(1/2)beta) was not altered. There were also differences between the two drugs. In all animals, the distribution half-life (T(1/2)alpha), T(1/2)beta, volume of central compartment (V(c)), V(d)beta, V(d)ss, and mean residence times (MRT) were greater and CL lower for bupivacaine than ropivacaine. For both drugs, protein binding was concentration-dependent and greater in pregnant ewes. In conclusion, the pharmacokinetics of ropivacaine and bupivacaine are altered by ovine pregnancy in a similar way. If these data are applicable to humans, an unintended intravascular injection of either drug could be expected to result in higher total serum concentrations in the pregnant than in the nonpregnant patient, but drug levels would decline at similar rates in both groups of individuals. However, differences between the two drugs, particularly in T(1/2)beta and MRT, may make ropivacaine preferable for use in obstetric anesthesia.
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Affiliation(s)
- A C Santos
- Department of Anesthesiology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York, USA
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Mather LE, McCall P, McNicol PL. Bupivacaine enantiomer pharmacokinetics after intercostal neural blockade in liver transplantation patients. Anesth Analg 1995; 80:328-35. [PMID: 7818121 DOI: 10.1097/00000539-199502000-00021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bupivacaine, being a racemic local anesthetic, exists as an equal mixture of its component enantiomers R(+)- and S(-)-bupivacaine, which behave pharmacokinetically as independent drugs after injection into the body. Intercostal neural blockade using bupivacaine was performed for postoperative analgesia in 12 patients after orthotopic liver transplantation. Arterial blood, sampled serially, was assayed by enantioselective high-performance liquid chromatography for R(+)- and S(-)-bupivacaine. The average of the simultaneous R(+):S(-) ratios of blood bupivacaine concentrations in the 12 patients was 0.74 (SD 0.11); however, the use of a population mean value or a mean value for any patient denies the time-dependence of this entity. The blood enantiomer concentration difference was reflected in the maximum measured concentrations which, after the first dose, were, respectively, 0.38 (SD 0.19) and 0.52 (SD 0.28) mg.L-1.100 mg-1 RS-bupivacaine administered (P = 0.0003). The difference in blood concentrations between the enantiomers, reflected by the R(+):S(-) ratio being less than unity, could be explained by a greater mean total body clearance and a larger apparent volume distribution of R(+)-bupivacaine. Elimination of both enantiomers was prolonged in these patients after liver transplantation compared to data from the literature, but there was no tendency for either enantiomer to accumulate selectively, even upon repeated dosing. We conclude that this demonstration of differences in pharmacokinetics (and, in laboratory studies, also in pharmacodynamics) between the bupivacaine enantiomers points to the need for future studies to recognize the enantiomeric duality of this local anesthetic.
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Affiliation(s)
- L E Mather
- Department of Anaesthesia and Pain Management, University of Sydney, Royal North Shore Hospital, St. Leonards, New South Wales, Australia
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Mather LE, McCall P, McNicol PL. Bupivacaine Enantiomer Pharmacokinetics After Intercostal Neural Blockade in Liver Transplantation Patients. Anesth Analg 1995. [DOI: 10.1213/00000539-199502000-00021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Mather LE, Rutten AJ, Plummer JL. Pharmacokinetics of bupivacaine enantiomers in sheep: influence of dosage regimen and study design. JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS 1994; 22:481-98. [PMID: 7473078 DOI: 10.1007/bf02353791] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Bupivacaine is used as a racemate. In previous studies the mean total body clearance of R(+)-bupivacaine was found to be greater than S(-)-bupivacaine by 65% after iv bolus dose of separate enantiomers and by 20% after iv infusion to steady state of racemate. The present studies were performed to determine whether different study designs using different iv dosage regimens could influence the pharmacokinetic parameters determined for either bupivacaine enantiomer. rac-Bupivacaine.HCl was administered iv to 6 adult Merino ewes by bolus, brief infusion, and prolonged infusion. Arterial blood concentrations of R(+)- and S(-)-bupivacaine were measured by enantioselective HPLC. These regimens consistently produced lower arterial blood concentrations of R(+)-bupivacaine than S(-)-bupivacaine due to R(+)-bupivacaine having a greater initial dilution volume by 16 (95% CI = 3-29)%, volume of distribution at steady state equilibrium by 32 (95% CI = 17-32)% and mean total body clearance by 28 (95% CI = 21-35)%. The slow half-life of R(+)-bupivacaine, however, was found to be 15 (95% CI = 0-31)% longer than that of S(-)-bupivacaine. The difference between enantiomers in mean total body clearance thus was similar to the previous study based upon infusion to steady state of rac-bupivacaine. Differences in pharmacokinetics attributable to the dosage regimen consisted of a greater mean total body clearance for R(+)-bupivacaine along with a smaller terminal half life with the bolus regimen and a longer half-life of S(-)-bupivacaine after prolonged infusion. Differences in pharmacokinetics between the bupivacaine enantiomers occurred consistently in both distribution and clearance but the magnitude of the effect was less than 50% in each case. Systematic differences in pharmacokinetics associated with the dosage regimen were found mainly in terminal half-life. Dosage regimen, thus, was found to influence the pharmacokinetic results found experimentally and is therefore a significant variable in its own right.
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Affiliation(s)
- L E Mather
- Department of Anaesthesia and Pain Management, University of Sydney, Royal North Shore Hospital, St Leonards, New South Wales, Australia
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Burm AG, van der Meer AD, van Kleef JW, Zeijlmans PW, Groen K. Pharmacokinetics of the enantiomers of bupivacaine following intravenous administration of the racemate. Br J Clin Pharmacol 1994; 38:125-9. [PMID: 7981012 PMCID: PMC1364857 DOI: 10.1111/j.1365-2125.1994.tb04335.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
1. The pharmacokinetics of R(+)-bupivacaine and S(-)-bupivacaine were investigated following a 10 min intravenous infusion of the racemate (dose 30 mg) in 10 healthy males. 2. The fractions unbound of R(+)- and S(-)-bupivacaine in pre-dose plasma were determined for each subject after in vitro addition of rac-bupivacaine (concentration of each enantiomer: approximately 300 ng ml-1). 3. The total plasma clearance of R(+)-bupivacaine (mean +/- s.d.: 0.395 +/- 0.076 l min-1) was greater (P < 0.0001) than that of S(-)-bupivacaine (0.317 +/- 0.067 l min-1). The volumes of distribution of R(+)-bupivacaine at steady state (84 +/- 29 l) and during the terminal log-linear phase (117 +/- 47 l) were larger (P < 0.0002) than those of S(-)-bupivacaine (54 +/- 20 l and 71 +/- 34 l, respectively). The terminal half-life (210 +/- 95 min) and mean residence time (215 +/- 74 min) of R(+)-bupivacaine were longer than those of S(-)-bupivacaine (157 +/- 77 min, P < 0.01, and 172 +/- 55 min, P < 0.02, respectively). 4. The free percentage of R(+)-bupivacaine (6.6 +/- 3.0 %) was greater (P < 0.0002) than that of S(-)-bupivacaine (4.5 +/- 2.1 %). 5. The plasma clearance of unbound R(+)-bupivacaine (7.26 +/- 3.60 1 min-1) was smaller (P < 0.01) than that of S(-)-bupivacaine (8.71 +/- 4.27 l min-1). Volumes of distribution based on unbound R(+)-bupivacaine concentrations (Vuss: 1576 +/- 934 l; Vu: 2233 +/- 1442 l) did not differ from those of S(-)-bupivacaine (Vuss: 1498 +/- 892 l; Vu: 1978 +/- 1302 l). 6. The enantioselective systemic disposition of bupivacaine can to a large extent be attributed to differences in the degree of plasma binding of the enantiomers.
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Affiliation(s)
- A G Burm
- Department of Anaesthesiology, University Hospital Leiden, The Netherlands
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Rutten AJ, Mather LE, McLean CF, Nancarrow C. Tissue distribution of bupivacaine enantiomers in sheep. Chirality 1993; 5:485-91. [PMID: 8240923 DOI: 10.1002/chir.530050702] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
rac-Bupivacaine HCl was infused intravenously to constant arterial blood drug concentrations in sheep using a regimen of 4 mg/min for 15 min followed by 1 mg/min to 24 h. At 24 h, arterial blood was sampled, the animal was killed with a bolus of KCl solution, then rapidly dissected and samples were obtained from heart, brain, lung, kidney, liver, muscle, fat, gut, and rumen. Tissue:blood distribution coefficients for (+)-(R)-bupivacaine exceeded those of (-)-(S)-bupivacaine (P < 0.05) for heart, brain, lung, fat, gut, and rumen by an overall mean of 43%. Blood:plasma distribution coefficients of (-)-(S)-bupivacaine exceeded those of (+)-(R)-bupivacaine by a mean of 29% and this offset the tissue:blood distribution coefficients so that the previously significant enantioselective differences disappeared. It is concluded that although enantioselectivity of bupivacaine distribution is shown by the measured tissue:blood distribution coefficients, it is not shown when tissue:plasma water distribution coefficients are calculated, suggesting that there is no intrinsic difference between the bupivacaine enantiomers in tissue affinity. Sheep given fatal intravenous bolus doses of rac-bupivacaine had significantly greater concentrations of (+)-(R)-bupivacaine than (-)-(S)-bupivacaine in brain (P = 0.028) and ventricle (P = 0.036); these could augment the greater myocardial toxicity of this enantiomer found in vitro.
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Affiliation(s)
- A J Rutten
- Department of Anaesthesia and Intensive Care, Flinders Medical Centre, Adelaide, Australia
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