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Marsella R, White S, Fadok VA, Wilson D, Mueller R, Outerbridge C, Rosenkrantz W. Equine allergic skin diseases: Clinical consensus guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 2023; 34:175-208. [PMID: 37154488 DOI: 10.1111/vde.13168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 02/03/2023] [Accepted: 02/26/2023] [Indexed: 05/10/2023]
Abstract
BACKGROUND Allergic skin diseases are common in horses worldwide. The most common causes are insect bites and environmental allergens. OBJECTIVES To review the current literature and provide consensus on pathogenesis, diagnosis, treatment and prevention. MATERIALS AND METHODS The authors reviewed the literature up to November 2022. Results were presented at North America Veterinary Dermatology Forum (2021) and European Veterinary Dermatology Congress (2021). The report was available to member organisations of the World Association for Veterinary Dermatology for feedback. CONCLUSIONS AND CLINICAL RELEVANCE Insect bite hypersensitivity (IBH) is the best characterised allergic skin disease. An immunoglobulin (Ig)E response against Culicoides salivary antigens is widely documented. Genetics and environmental factors play important roles. Tests with high sensitivity and specificity are lacking, and diagnosis of IBH is based on clinical signs, seasonality and response to insect control. Eosinophils, interleukin (IL)-5 and IL-31 are explored as therapeutic targets. Presently, the most effective treatment is insect avoidance. Existing evidence does not support allergen-specific immunotherapy (ASIT) using commercially available extracts of Culicoides. Hypersensitivity to environmental allergens (atopic dermatitis) is the next most common allergy. A role for IgE is supported by serological investigation, skin test studies and positive response to ASIT. Prospective, controlled, randomised studies are limited, and treatment relies largely on glucocorticoids, antihistamines and ASIT based on retrospective studies. Foods are known triggers for urticaria, yet their role in pruritic dermatitis is unknown. Recurrent urticaria is common in horses, yet our understanding is limited and focussed on IgE and T-helper 2 cell response. Prospective, controlled studies on treatments for urticaria are lacking. Glucocorticoids and antihistamines are primary reported treatments.
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Affiliation(s)
- R Marsella
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - S White
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - V A Fadok
- Zoetis, US PET CARE, Bellaire, Texas, USA
| | - D Wilson
- School of Clinical Veterinary Sciences, University of Bristol, Bristol, UK
| | - R Mueller
- Medizinische Keleintierklinik, Zentrum für klinische Tiermedizin, LMU, Munich, Germany
| | - C Outerbridge
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, USA
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Gao X, Li C, He R, Zhang Y, Wang B, Zhang ZH, Ho CT. Research advances on biogenic amines in traditional fermented foods: Emphasis on formation mechanism, detection and control methods. Food Chem 2022. [DOI: 10.1016/j.foodchem.2022.134911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rosa B. Equine Drug Transporters: A Mini-Review and Veterinary Perspective. Pharmaceutics 2020; 12:pharmaceutics12111064. [PMID: 33171593 PMCID: PMC7695171 DOI: 10.3390/pharmaceutics12111064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 11/16/2022] Open
Abstract
Xenobiotic transport proteins play an important role in determining drug disposition and pharmacokinetics. Our understanding of the role of these important proteins in humans and pre-clinical animal species has increased substantially over the past few decades, and has had an important impact on human medicine; however, veterinary medicine has not benefitted from the same quantity of research into drug transporters in species of veterinary interest. Differences in transporter expression cause difficulties in extrapolation of drug pharmacokinetic parameters between species, and lack of knowledge of species-specific transporter distribution and function can lead to drug–drug interactions and adverse effects. Horses are one species in which little is known about drug transport and transporter protein expression. The purpose of this mini-review is to stimulate interest in equine drug transport proteins and comparative transporter physiology.
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Affiliation(s)
- Brielle Rosa
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, TRW 2D01, Calgary, Alberta T2N 4Z6, Canada
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Kuroda T, Nagata SI, Tamura N, Mita H, Kusano K, Mizobe F, Takizawa Y, Fukuda K, Kasashima Y. Pharmacokinetics and pharmacodynamics of olopatadine following administration via nasogastric tube to healthy horses. Am J Vet Res 2019; 80:689-695. [PMID: 31246121 DOI: 10.2460/ajvr.80.7.689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the pharmacokinetics and antihistaminic effects (pharmacodynamics) of olopatadine in a small population of healthy horses after administration via nasogastric tube. ANIMALS 4 healthy adult Thoroughbreds. PROCEDURES Olopatadine (0.1 mg/kg, once) was administered via nasogastric tube. Blood samples were collected at predetermined time points for pharmacokinetic analyses of the drug in plasma. Olopatadine effects were investigated by measurement of cutaneous wheals induced by ID histamine injection (0.1 mL [10 μg]/injection) at predetermined time points. Inhibition effect ratios were calculated on the basis of measured wheal size (area) after versus before olopatadine administration. RESULTS Mean ± SD maximum plasma olopatadine concentration was 48.8 ± 11.0 ng/mL approximately 1.5 hours after administration. Median terminal half-life was 6.11 hours. Mean ± SD maximal effect was 88.2 ± 4.9% inhibition approximately 3.5 hours after drug delivery, and the inhibition effect remained > 80% for 12.5 hours after treatment. No signs of adverse clinical effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested olopatadine may have a strong, long-term inhibitory effect against histamine-induced wheals in the skin of horses. Clinical research with a larger number of horses is warranted.
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Virkel G, Ballent M, Lanusse C, Lifschitz A. Role of ABC Transporters in Veterinary Medicine: Pharmaco- Toxicological Implications. Curr Med Chem 2019; 26:1251-1269. [DOI: 10.2174/0929867325666180201094730] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/14/2017] [Accepted: 12/22/2017] [Indexed: 01/10/2023]
Abstract
Unlike physicians, veterinary practitioners must deal with a number of animal species with crucial differences in anatomy, physiology and metabolism. Accordingly, the pharmacokinetic behaviour, the clinical efficacy and the adverse or toxic effects of drugs may differ across domestic animals. Moreover, the use of drugs in food-producing species may impose a risk for humans due to the generation of chemical residues in edible products, a major concern for public health and consumer's safety. As is clearly known in human beings, the ATP binding cassette (ABC) of transport proteins may influence the bioavailability and elimination of numerous drugs and other xenobiotics in domestic animals as well. A number of drugs, currently available in the veterinary market, are substrates of one or more transporters. Therefore, significant drug-drug interactions among ABC substrates may have unpredictable pharmacotoxicological consequences in different species of veterinary interest. In this context, different investigations revealed the major relevance of P-gp and other transport proteins, like breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs), in both companion and livestock animals. Undoubtedly, the discovery of the ABC transporters and the deep understanding of their physiological role in the different species introduced a new paradigm into the veterinary pharmacology. This review focuses on the expression and function of the major transport proteins expressed in species of veterinary interest, and their impact on drug disposition, efficacy and toxicity.
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Affiliation(s)
- Guillermo Virkel
- Laboratorio de Farmacologia, Centro de Investigacion Veterinaria de Tandil (CIVETAN-CONICETCICPBA), Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (FCV-UNCPBA), Campus Universitario (Los Ombues y Reforma Universitaria), (7000) Tandil, Prov. de Buenos Aires, Argentina
| | - Mariana Ballent
- Laboratorio de Farmacologia, Centro de Investigacion Veterinaria de Tandil (CIVETAN-CONICETCICPBA), Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (FCV-UNCPBA), Campus Universitario (Los Ombues y Reforma Universitaria), (7000) Tandil, Prov. de Buenos Aires, Argentina
| | - Carlos Lanusse
- Laboratorio de Farmacologia, Centro de Investigacion Veterinaria de Tandil (CIVETAN-CONICETCICPBA), Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (FCV-UNCPBA), Campus Universitario (Los Ombues y Reforma Universitaria), (7000) Tandil, Prov. de Buenos Aires, Argentina
| | - Adrián Lifschitz
- Laboratorio de Farmacologia, Centro de Investigacion Veterinaria de Tandil (CIVETAN-CONICETCICPBA), Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (FCV-UNCPBA), Campus Universitario (Los Ombues y Reforma Universitaria), (7000) Tandil, Prov. de Buenos Aires, Argentina
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Kigen G, Edwards G. Drug-transporter mediated interactions between anthelminthic and antiretroviral drugs across the Caco-2 cell monolayers. BMC Pharmacol Toxicol 2017; 18:20. [PMID: 28468637 PMCID: PMC5415745 DOI: 10.1186/s40360-017-0129-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 02/28/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Drug interactions between antiretroviral drugs (ARVs) and anthelminthic drugs, ivermectin (IVM) and praziquantel (PZQ) were assessed by investigating their permeation through the Caco-2 cell monolayers in a transwell. The impact of anthelminthics on the transport of ARVs was determined by assessing the apical to basolateral (AP → BL) [passive] and basolateral to apical (BL → AP) [efflux] directions alone, and in presence of an anthelminthic. The reverse was conducted for the assessment of the influence of ARVs on anthelminthics. METHODS Samples from the AP and BL compartments were taken at 60, 120, 180 and 240 min and quantified either by HPLC or radiolabeled assay using a liquid scintillating counter for the respective drugs. Transepithelial resistance (TEER) was used to assess the integrity of the monolayers. The amount of compound transported per second (apparent permeability, Papp) was calculated for both AP to BL (PappAtoB), and BL to AP (PappBtoA) movements. Samples collected after 60 min were used to determine the efflux ratio (ER), quotient of secretory permeability and absorptive permeability (PappBL-AP/PappAP-BL). The reverse, (PappAP-BL/PappBL-AP) constituted the uptake ratio. The impact of SQV, EFV and NVP on the transport of both IVM and PZQ were investigated. The effect of LPV on the transport of IVM was also determined. The influence of IVM on the transport of SQV, NVP, LPV and EFV; as well as the effect PZQ on the transport of SQV of was also investigated, and a two-tailed p value of <0.05 was considered significant. RESULTS IVM significantly inhibited the efflux transport (BL → AP movement) of LPV (ER; 6.7 vs. 0.8, p = 0.0038) and SQV (ER; 3.1 vs. 1.2 p = 0.00328); and increased the efflux transport of EFV (ER; 0.7 vs. 0.9, p = 0.031) suggesting the possibility of drug transporter mediated interactions between the two drugs. NVP increased the efflux transport of IVM (ER; 0.8 vs. 1.8, p = 0.0094). CONCLUSIONS The study provides in vitro evidence of potential interactions between IVM, an anthelminthic drug with antiretroviral drugs; LPV, SQV, NVP and EFV. Further investigations should be conducted to investigate the possibility of in vivo interactions.
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Affiliation(s)
- Gabriel Kigen
- Department of Pharmacology and Toxicology, Moi University School of Medicine, P.O. Box 4606, 30100 Eldoret, Kenya
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, L69 3GE UK
| | - Geoffrey Edwards
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, L69 3GE UK
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El-Kommos ME, El-Gizawy SM, Atia NN, Hosny NM. Determination of Some Non-sedating Antihistamines via Their Native Fluorescence and Derivation of Some Quantitative Fluorescence Intensity - Structure Relationships. J Fluoresc 2015; 25:1695-709. [DOI: 10.1007/s10895-015-1656-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/09/2015] [Indexed: 10/23/2022]
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Javid FS, Shafaati A, Zarghi A. APPLICATION OF SDS MICELLES AS CARRIERS FOR RELIABLE DETERMINATION OF FEXOFENADINE AND ITS IMPURITIES IN BULK AND PHARMACEUTICAL FORMULATIONS BY CAPILLARY MICELLAR ELECTROPHORESIS. J LIQ CHROMATOGR R T 2013. [DOI: 10.1080/10826076.2012.738615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Farin Sattary Javid
- a Pharmaceutical Chemistry , School of Pharmacy, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Alireza Shafaati
- a Pharmaceutical Chemistry , School of Pharmacy, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Afshin Zarghi
- a Pharmaceutical Chemistry , School of Pharmacy, Shahid Beheshti University of Medical Sciences , Tehran , Iran
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Kuroda T, Nagata SI, Takizawa Y, Tamura N, Kusano K, Mizobe F, Hariu K. Pharmacokinetics and pharmacodynamics of d-chlorpheniramine following intravenous and oral administration in healthy Thoroughbred horses. Vet J 2013; 197:433-7. [DOI: 10.1016/j.tvjl.2013.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 01/29/2013] [Accepted: 02/04/2013] [Indexed: 11/26/2022]
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Qiang F, Shin HJ, Lee BJ, Han HK. Enhanced systemic exposure of fexofenadine via the intranasal administration of chitosan-coated liposome. Int J Pharm 2012; 430:161-6. [PMID: 22525082 DOI: 10.1016/j.ijpharm.2012.04.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/05/2012] [Accepted: 04/05/2012] [Indexed: 12/01/2022]
Abstract
The present study aimed to develop the intranasal delivery system of fexofenadine for the prolonged drug release via the preparation of mucoadhesive liposome. By using thin layer film hydration method, liposome of fexofenadine was prepared with DPPC/DPPG, resulting in the small lipid vesicles (359 ± 5.5 nm) with narrow size distribution (PI<0.1). Subsequently, the surface of anionic liposome was coated by chitosan and in vitro characteristics of liposomes were evaluated along with the pharmacokinetic studies in rats. Chitosan coated liposomes were stable for 6-month storage at 4 °C without any significant size change and drug leakage. Furthermore, it exhibited strong mucoadhesive properties in mucin adsorption test, which was 3-fold higher than uncoated liposomes. Compared to the oral delivery of powder formulation, the intranasal delivery of fexofenadine significantly (p<0.05) increased systemic exposure of fexofenadine in rats. Particularly, the intranasal administration of chitosan coated liposome exhibited approximately 5 fold enhancement of AUC with more sustained drug release in rats compared to the oral delivery. In conclusion, intranasal administration of chitosan coated liposome appeared to be effective to enhance the bioavailability as well as prolonged exposure of fexofenadine in rats.
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Affiliation(s)
- Fu Qiang
- College of Pharmacy, Dongguk University, Pil-dong-3-ga, Jung-gu, Seoul 100-715, Republic of Korea
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Gundogdu E, Mangas-Sanjuan V, Gonzalez-Alvarez I, Bermejo M, Karasulu E. In vitro–in situ permeability and dissolution of fexofenadine with kinetic modeling in the presence of sodium dodecyl sulfate. Eur J Drug Metab Pharmacokinet 2011; 37:65-75. [DOI: 10.1007/s13318-011-0059-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022]
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Piao HM, Balakrishnan P, Cho HJ, Kim H, Kim YS, Chung SJ, Shim CK, Kim DD. Preparation and evaluation of fexofenadine microemulsion for intranasal delivery. Int J Pharm 2010; 395:S0378-5173(10)00403-5. [PMID: 20685383 DOI: 10.1016/j.ijpharm.2010.05.041] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/24/2010] [Accepted: 05/27/2010] [Indexed: 01/16/2023]
Abstract
To enhance the solubility and bioavailability of poorly absorbable fexofenadine, microemulsion system composed of oil, surfactant and co-surfactant was developed for intranasal delivery. Phase behavior, particle size, viscosity and solubilization capacity of the microemulsion system were characterized. Histopathology and in vivo nasal absorption of the optimized microemulsion formulations were also investigated in rats. A single isotropic region was found in the pseudo-ternary phase diagrams developed at various ratios with Lauroglycol 90 as oil, Labrasol as surfactant and Plurol oleiqueCC49 or its mixture with PEG-400 (1:1) as cosurfactant. An increase in the microemulsion region in pseudo-ternary phase systems was observed with increased surfactant concentration. The optimized microemulsion formulations showed higher solubulization of fexofenadine, i.e., F1 (22.64mg/mL) and F2 (22.98mg/mL), compared to its intrinsic water solubility (1.51mg/mL). Nasal absorption of fexofenadine from these microemulsions was found to be fairly rapid. T(max) was observed within 5min after intranasal administration at 1.0mg/kg dose, and the absolute bioavailability (0-4h) was about 68% compared to the intravenous administration in rats. Our results suggested that these microemulsion formulations could be used as an effective intranasal dosage form for the rapid-onset delivery of fexofenadine.
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Affiliation(s)
- Hong-Mei Piao
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
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Preparation and evaluation of spray-dried hyaluronic acid microspheres for intranasal delivery of fexofenadine hydrochloride. Eur J Pharm Sci 2010; 40:9-15. [DOI: 10.1016/j.ejps.2010.02.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/22/2010] [Accepted: 02/03/2010] [Indexed: 11/23/2022]
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GRABOWSKI T, JAROSZEWSKI JJ. Bioavailability of veterinary drugsin vivoandin silico. J Vet Pharmacol Ther 2009; 32:249-57. [DOI: 10.1111/j.1365-2885.2008.01034.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Olsén L, Bondesson U, Broström H, Tjälve H, Ingvast-Larsson C. Cetirizine in horses: Pharmacokinetics and pharmacodynamics following repeated oral administration. Vet J 2008; 177:242-9. [PMID: 17581764 DOI: 10.1016/j.tvjl.2007.03.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/27/2007] [Accepted: 03/28/2007] [Indexed: 11/25/2022]
Abstract
The pharmacokinetics of the histamine H(1)-antagonist cetirizine and its effect on histamine-induced cutaneous wheal formation were studied in six healthy horses following repeated oral administration. After three consecutive administrations of cetirizine (0.2 mg/kg body weight, bw) every 12h, the trough plasma concentration of cetirizine was 16+/-4 ng/mL (mean+/-SD) and the wheal formation was inhibited by 45+/-23%. After four additional administrations of cetirizine (0.4 mg/kg bw) every 12 h, the trough plasma concentration was 48+/-15 ng/mL and the wheal formation was inhibited by 68+/-11%. The terminal half-life was about 5.8 h. A pharmacokinetic/pharmacodynamic link model showed that the maximal inhibition of wheal formation was about 95% and the EC(50) about 18 ng/mL. It is concluded that cetirizine in doses of 0.2-0.4 mg/kg bw administered at 12 h intervals exhibits favourable pharmacokinetic and pharmacodynamic properties without causing visible side effects, and the drug may therefore be a useful antihistamine in equine medicine.
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Affiliation(s)
- Lena Olsén
- Division of Pathology, Pharmacology and Toxicology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Cunningham FM, Dunkel B. Equine recurrent airway obstruction and insect bite hypersensitivity: understanding the diseases and uncovering possible new therapeutic approaches. Vet J 2007; 177:334-44. [PMID: 18023376 DOI: 10.1016/j.tvjl.2007.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 10/02/2007] [Accepted: 10/03/2007] [Indexed: 01/26/2023]
Abstract
Recurrent airway obstruction (RAO) and insect bite hypersensitivity (IBH) are allergic conditions that are commonly encountered in the horse. Whilst complete allergen avoidance is an effective management strategy for both diseases, this may not be achievable in all cases and treatment options are therefore required. The inflammatory response is the main therapeutic target for glucocorticoids given to horses with RAO and severe cases of IBH, whilst the bronchodilators used in RAO primarily target airway smooth muscle. Such drugs are effective in most but not all individuals and there may be unwanted adverse effects. This article will review how knowledge of drug action and the pathogenesis of RAO and IBH can be utilised to identify potential targets for novel therapeutic agents that, in the longer term, may be safer and/or more effective in managing the allergic horse.
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Affiliation(s)
- Fiona M Cunningham
- Department of Veterinary Basic Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK.
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Chen C. Some pharmacokinetic aspects of the lipophilic terfenadine and zwitterionic fexofenadine in humans. Drugs R D 2007; 8:301-14. [PMID: 17767395 DOI: 10.2165/00126839-200708050-00004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fexofenadine, an active metabolite of the second-generation histamine H1 receptor antagonist (antihistamine) terfenadine, does not have the disadvantage of QT prolongation. In addition, unlike first-generation antihistamines, it is associated with few CNS adverse effects. Chemically, fexofenadine has a zwitterionic structure that makes it an interesting molecule for use as an oral drug. Fexo-fenadine has negligible hepatic metabolism in humans, and is recovered mainly in the faeces in an unchanged form after oral administration. The absolute oral bioavailability of fexofenadine in humans is not known because of a lack of studies of intravenous administration of this agent. Its apparent elimination half-life (t1/2) ranges from 3 to 17 hours and is highly dependent on study design, i.e. the length of blood sampling. This large discrepancy might be associated with a 'flip-flop' phenomenon caused by slow absorption of the zwitterionic molecule. This review summarises the available literature related to the absorption, elimination and excretion of fexofenadine and terfenadine. Based on these data, the volume of distribution, t1/2 and oral bioavailability of fexofenadine in humans are estimated. Understanding these pharmacokinetic aspects of this drug might be very useful for medicinal chemists utilising fexofenadine/terfenadine as an example for designing zwitterionic compounds to combat cardiotoxicity and other issues related to basic and lipophilic molecules.
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Affiliation(s)
- Chen Chen
- Department of Medicinal Chemistry, Neurocrine Biosciences, Inc., San Diego, California 92130, USA.
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Olsén L, Ingvast-Larsson C, Bondesson U, Broström H, Tjälve H, Larsson P. Cetirizine in horses: pharmacokinetics and effect of ivermectin pretreatment. J Vet Pharmacol Ther 2007; 30:194-200. [PMID: 17472650 DOI: 10.1111/j.1365-2885.2007.00850.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pharmacokinetics of the histamine H(1)-antagonist cetirizine and the effects of pretreatment with the antiparasitic macrocyclic lactone ivermectin on the pharmacokinetics of cetirizine were studied in horses. After oral administration of cetirizine at 0.2 mg/kg bw, the mean terminal half-life was 3.4 h (range 2.9-3.7 h) and the maximal plasma concentration 132 ng/mL (101-196 ng/mL). The time to reach maximal plasma concentration was 0.7 h (0.5-0.8 h). Ivermectin (0.2 mg/kg bw) given orally 1.5 h before cetirizine did not affect its pharmacokinetics. However, ivermectin pretreatment 12 h before cetirizine increased the area under the plasma concentration-time curve by 60%. The maximal plasma concentration, terminal half-life and mean residence time also increased significantly following the 12 h pretreatment. Ivermectin is an inhibitor of P-glycoprotein, which is a major drug efflux transporter in cellular membranes at various sites. The elevated plasma levels of cetirizine following the pretreatment with ivermectin may mainly be due to decreased renal secretion, related to inhibition of the P-glycoprotein in the proximal tubular cells of the kidney. The pharmacokinetic properties of cetirizine have characteristics which are suitable for an antihistamine, and this substance may be a useful drug in horses.
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Affiliation(s)
- L Olsén
- Division of Pathology, Pharmacology and Toxicology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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TJÄLVE H, LARSSON P. KN07 Extra hepatic metabolism of xenobiotics, focusing on veterinary species. J Vet Pharmacol Ther 2006. [DOI: 10.1111/j.1365-2885.2006.00762_1.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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