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Govendir M, Vogelnest L, Shapiro AJ, Marschner C, Kimble B. Pharmacokinetic profile of oral and subcutaneous administration of paracetamol in the koala (Phascolarctos cinereus) and prediction of its analgesic efficacy. PLoS One 2024; 19:e0300703. [PMID: 38630750 PMCID: PMC11023281 DOI: 10.1371/journal.pone.0300703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 03/04/2024] [Indexed: 04/19/2024] Open
Abstract
The pharmacokinetic profile of paracetamol in koalas is described when administered orally at 15 mg/kg; followed by the same dose, administered every 12 hours (hrs), repeated five times. After the initial oral administration, the median (range) maximal plasma concentration (Cmax), the time Cmax was reached (Tmax) and elimination half-life (t1/2) were 16.93 μg/mL (13.66 to 20.25 μg/mL); 4 hrs (4 to 8 hrs) and 5.54 hrs (4.66 to 7.67 hrs), respectively. When paracetamol was administered orally at 15 mg/mL every 12 hrs, the trough total plasma concentration range remained comparable to the therapeutic range in humans i.e. 4 to 20 μg/mL that is known to provide some analgesia. However, there is a smaller proportion of free drug (i.e. not bound to plasma proteins; and the active form) available in koala plasma (approximately 40% unbound) compared to human plasma (approximately 80% unbound). Consequently, even when there are similar total drug plasma concentrations in both koala and human plasma, the therapeutic efficacy may be reduced in koalas compared to humans. The initial oral dose and subsequent twice daily doses resulted in no obvious adverse effects in any koala. Haematology, plasma electrolyte and biochemical analyte values remained within their reference ranges eight hrs after the last dose but there was a significant change in alanine transaminase (ALT) levels (an increase), and in total protein (a decrease) (both p = 0.03). A dose of 15 mg/kg was also administered as a subcutaneous injection, diluted 50:50 with saline, to two koalas. As the oral formulation and the subcutaneous administration resulted in comparable absorption, the study focused on the oral profile. Based on these results there is an argument to recommend a slight increase in the oral paracetamol dose for the koala, however further investigation is required to confirm whether repeated administration of a slightly higher dose may be associated with more severe or additional significant changes in haematology, electrolytes or biochemical analytes. However, a preferable recommendation would be to administer this dosage of paracetamol in combination with another analgesic such as tramadol, as a subcutaneous injection, to improve efficacy.
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Affiliation(s)
- Merran Govendir
- Sydney School of Veterinary Science, The University of Sydney, Sydney, Australia
| | - Larry Vogelnest
- Taronga Conservation Society Australia, Mosman, NSW, Sydney, Australia
| | - Amanda J. Shapiro
- Sydney School of Veterinary Science, The University of Sydney, Sydney, Australia
| | - Caroline Marschner
- Sydney School of Veterinary Science, The University of Sydney, Sydney, Australia
| | - Benjamin Kimble
- Sydney School of Veterinary Science, The University of Sydney, Sydney, Australia
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Sun P, Zhao T, Xiao H, Wang J, Zhang S, Cao X. The bioavailability and pharmacokinetics of an amoxicillin-clavulanic acid granular combination after intravenous and oral administration in swine. J Vet Pharmacol Ther 2020; 44:126-130. [PMID: 33063331 DOI: 10.1111/jvp.12916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/15/2020] [Accepted: 09/20/2020] [Indexed: 12/01/2022]
Abstract
The pharmacokinetic behaviours of amoxicillin (AMX) and clavulanic acid (CA) in swine were studied after either an intravenous or oral administration of AMX (10 mg/kg) and CA (2.5 mg/kg). The concentrations of these two medicines in swine plasma were determined using high-performance liquid chromatographic-tandem mass spectrometry, and the data were analysed using a noncompartmental model with the WinNonlin software. After intravenous administration, both substances were absorbed rapidly and reached their effective therapeutic concentration quickly. CA was eliminated more slowly compared with AMX. Moreover, the distribution volume of AMX was larger than that of CA, suggesting that AMX could penetrate tissues better. After oral administration of the granular formulation, no significant difference was observed in the mean elimination half-life value between AMX and CA. The mean maximal plasma concentrations of AMX and CA, reached after 1.14 and 1.32 hr, were 2.58 and 1.91 μg/m, respectively. The mean oral bioavailability of AMX and CA was 23.6% and 26.4%, respectively. After oral administration, the T>MIC50 for three common respiratory pathogens was over 6.12 hr. Therefore, oral administration could be more effective in the clinical therapy of pigs, especially when administered twice daily.
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Affiliation(s)
- Pan Sun
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Laboratory of Quality & Safety Risk Assessment for Animal Products on Chemical Hazards (Beijing), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China
| | - Tingting Zhao
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Laboratory of Quality & Safety Risk Assessment for Animal Products on Chemical Hazards (Beijing), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China
| | - Hongzhi Xiao
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Laboratory of Quality & Safety Risk Assessment for Animal Products on Chemical Hazards (Beijing), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China
| | - Jie Wang
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Laboratory of Quality & Safety Risk Assessment for Animal Products on Chemical Hazards (Beijing), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China
| | - Suxia Zhang
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Laboratory of Quality & Safety Risk Assessment for Animal Products on Chemical Hazards (Beijing), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China.,Key Laboratory of Detection for Veterinary Drug Residues and Illegal Additives, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China
| | - Xingyuan Cao
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Laboratory of Quality & Safety Risk Assessment for Animal Products on Chemical Hazards (Beijing), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China.,Key Laboratory of Detection for Veterinary Drug Residues and Illegal Additives, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Beijing, China
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