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Odell EP, Jabassini N, Schniedewind B, Pease-Raissi SE, Frymoyer A, Christians U, Green AJ, Chan JR, Ostrem BEL. Minimum effective dose of clemastine in a mouse model of preterm white matter injury. Pediatr Res 2024:10.1038/s41390-024-03326-w. [PMID: 38942888 DOI: 10.1038/s41390-024-03326-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 05/06/2024] [Accepted: 05/31/2024] [Indexed: 06/30/2024]
Abstract
BACKGROUND Preterm white matter injury (PWMI) is the most common cause of brain injury in premature neonates. PWMI involves a differentiation arrest of oligodendrocytes, the myelinating cells of the central nervous system. Clemastine was previously shown to induce oligodendrocyte differentiation and myelination in mouse models of PWMI at a dose of 10 mg/kg/day. The minimum effective dose (MED) of clemastine is unknown. Identification of the MED is essential for maximizing safety and efficacy in neonatal clinical trials. We hypothesized that the MED in neonatal mice is lower than 10 mg/kg/day. METHODS Mouse pups were exposed to normoxia or hypoxia (10% FiO2) from postnatal day 3 (P3) through P10. Vehicle or clemastine at one of four doses (0.5, 2, 7.5 or 10 mg/kg/day) was given to hypoxia-exposed pups. Myelination was assessed at age P14 and 10 weeks to determine the MED. Clemastine pharmacokinetics were evaluated at steady-state on day 8 of treatment. RESULTS Clemastine rescued hypoxia-induced hypomyelination with a MED of 7.5 mg/kg/day. Pharmacokinetic analysis of the MED revealed Cmax 44.0 ng/mL, t1/2 4.6 h, and AUC24 280.1 ng*hr/mL. CONCLUSIONS Based on these results, myelination-promoting exposures should be achievable with oral doses of clemastine in neonates with PWMI. IMPACT Preterm white matter injury (PWMI) is the most common cause of brain injury and cerebral palsy in premature neonates. Clemastine, an FDA-approved antihistamine, was recently identified to strongly promote myelination in a mouse model of PWMI and is a possible treatment. The minimum effective dose in neonatal rodents is unknown and is critical for guiding dose selection and balancing efficacy with toxicity in future clinical trials. We identified the minimum effective dose of clemastine and the associated pharmacokinetics in a murine chronic hypoxia model of PWMI, paving the way for a future clinical trial in human neonates.
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Affiliation(s)
- Elizabeth P Odell
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Nora Jabassini
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Björn Schniedewind
- iC42 Clinical Research and Development, Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sarah E Pease-Raissi
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Adam Frymoyer
- Department of Pediatrics, Stanford University, Palo Alto, CA, USA
| | - Uwe Christians
- iC42 Clinical Research and Development, Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Ari J Green
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Jonah R Chan
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Bridget E L Ostrem
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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Odell E, Jabassini N, Schniedewind B, Pease-Raissi SE, Frymoyer A, Christians U, Green AJ, Chan JR, Ostrem BEL. Minimum Effective Dose of Clemastine in a Mouse Model of Preterm White Matter Injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.08.578953. [PMID: 38464078 PMCID: PMC10925142 DOI: 10.1101/2024.02.08.578953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Background Preterm white matter injury (PWMI) is the most common cause of brain injury in premature neonates. PWMI involves a differentiation arrest of oligodendrocytes, the myelinating cells of the central nervous system. Clemastine was previously shown to induce oligodendrocyte differentiation and myelination in mouse models of PWMI at a dose of 10 mg/kg/day. The minimum effective dose (MED) of clemastine is unknown. Identification if the MED is essential for maximizing safety and efficacy in neonatal clinical trials. We hypothesized that the MED in neonatal mice is lower than 10 mg/kg/day. Methods Mouse pups were exposed to normoxia or hypoxia (10% FiO 2 ) from postnatal day 3 (P3) through P10. Vehicle or clemastine fumarate at one of four doses (0.5, 2, 7.5 or 10 mg/kg/day) was given orally to hypoxia-exposed pups. At P14, myelination was assessed by immunohistochemistry and electron microscopy to determine the MED. Clemastine pharmacokinetics were evaluated at steady-state on day 8 of treatment. Results Clemastine rescued hypoxia-induced hypomyelination with a MED of 7.5 mg/kg/day. Pharmacokinetic analysis of the MED revealed C max 44.0 ng/mL, t 1/2 4.6 hours, and AUC 24 280.1 ng*hr/mL. Conclusion Based on these results, myelination-promoting exposures should be achievable with oral doses of clemastine in neonates with PWMI. Key Points Preterm white matter injury (PWMI) is the most common cause of brain injury and cerebral palsy in premature neonates.Clemastine, an FDA-approved antihistamine, was recently identified to strongly promote myelination in a mouse model of PWMI and is a possible treatment.The minimum effective dose in neonatal rodents is unknown and is critical for guiding dose selection and balancing efficacy with toxicity in future clinical trials.We identified the minimum effective dose of clemastine and the associated pharmacokinetics in a murine chronic hypoxia model of PWMI, paving the way for a future clinical trial in human neonates.
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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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Kawakami S, Nagasawa Y, Hagiwara-Nagasawa M, Omura K, Aimoto M, Takahara A. Torsadogenic potential of a novel remyelinating drug clemastine for multiple sclerosis assessed in the rabbit proarrhythmia model. J Pharmacol Sci 2020; 144:123-128. [PMID: 32921393 DOI: 10.1016/j.jphs.2020.08.003] [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: 03/11/2020] [Revised: 07/27/2020] [Accepted: 08/17/2020] [Indexed: 11/24/2022] Open
Abstract
We assessed the torsadogenic effects of a novel remyelinating drug clemastine for multiple sclerosis using an in vivo proarrhythmia model of acute atrioventricular block rabbit, since the drug has been demonstrated to suppress the human ether-á-go-go related gene (hERG) K+ channels. Bradycardia was induced by atrioventricular node ablation in isoflurane-anesthetized New Zealand White rabbits (n = 5), and the ventricle was electrically driven at 60 beats/min throughout the experiment, except when extrasystoles appeared. Intravenous administration of clinically relevant dose of 0.03 mg/kg of clemastine and 10-times higher dose of 0.3 mg/kg hardly affected the QT interval or duration of the monophasic action potential (MAP) of the ventricle. Additional administration of clemastine at 3 mg/kg significantly increased the QT interval, MAP duration and the short-term variability of repolarization. Meanwhile, the premature ventricular contractions with R on T phenomenon were observed in 3 out of 5 animals, and torsades de pointes arrhythmias were detected in 1 out of 5 animals. These results suggest that the torsadogenic potential of clemastine is obviously observed in the acute atrioventricular block rabbit, which will not appear within the prescribed dose for multiple sclerosis.
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Affiliation(s)
- Satoshi Kawakami
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Yoshinobu Nagasawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Mihoko Hagiwara-Nagasawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan; Department of Pharmacology, Faculty of Medicine, Toho University, Ota-ku, Tokyo 143-8540, Japan
| | - Kensuke Omura
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Megumi Aimoto
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Akira Takahara
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan.
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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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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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Tydén E, Bjornstrom H, Tjälve H, Larsson P. Expression and localization of BCRP, MRP1 and MRP2 in intestines, liver and kidney in horse. J Vet Pharmacol Ther 2011; 33:332-40. [PMID: 20646193 DOI: 10.1111/j.1365-2885.2009.01140.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The gene and protein expression and the cellular localization of the ABC transport proteins breast cancer resistance protein (BCRP), multidrug resistance-associated protein 1 (MRP1) and multidrug resistance-associated protein 2 (MRP2) have been examined in the intestines, liver and kidney in horse. High gene and protein expression of BCRP and MRP2 were found in the small intestines, with cellular localization in the apical membranes of the enterocytes. In the liver, MRP2 was present in the bile canalicular membranes of the hepatocytes, whereas BCRP was localized in the cytoplasm of hepatocytes in the peripheral parts of the liver lobuli. In the kidney both BCRP and MRP2 were predominantly present in the distal tubuli and in the loops of Henle. In most tissues, the gene and protein expression of MRP1 were much lower than for BCRP and MRP2. Immunostaining of MRP1 was detectable only in the intestines and with localization in the cytoplasm of enterocytes in the caecum and colon and in the cells of serous acini of Brunner's glands in the duodenum and the upper jejunum. The latter cells were also stained for BCRP, but not for MRP2. Many drugs used in horse are substrates for one or more of the ABC transport proteins. These transporters may therefore have important functions for oral bioavailability, distribution and excretion of substrate compounds in horse.
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Affiliation(s)
- E Tydén
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Tevell Aberg A, Löfgren H, Bondesson U, Hedeland M. Structural elucidation of N-oxidized clemastine metabolites by liquid chromatography/tandem mass spectrometry and the use of Cunninghamella elegans to facilitate drug metabolite identification. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:1447-1456. [PMID: 20411584 DOI: 10.1002/rcm.4535] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Cunninghamella elegans is a filamentous fungus that has been shown to biotransform drugs into the same metabolites as mammals. In this paper we describe the use of C. elegans to aid the identification of clemastine metabolites since high concentrations of the metabolites were produced and MS(n) experiments were facilitated. The combination of liquid chromatography and tandem mass spectrometry with two different ionization techniques and hydrogen/deuterium exchange were used for structural elucidation of the clemastine metabolites. Norclemastine, four isomers of hydroxylated clemastine, and two N-oxide metabolites were described for the first time in C. elegans incubations. The N-oxidations were confirmed by hydrogen/deuterium exchange and deoxygenation (-16 Da) upon atmospheric pressure chemical ionization mass spectrometry. By MS(n) fragmentation it was concluded that two of the hydroxylated metabolites were oxidized on the methylpyrridyl moiety, one on the aromatic ring with the chloro substituent, and one on the aromatic ring without the chlorine.
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Affiliation(s)
- Annica Tevell Aberg
- Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), Uppsala, Sweden.
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Tydén E, Tallkvist J, Tjälve H, Larsson P. P-glycoprotein in intestines, liver, kidney and lymphocytes in horse. J Vet Pharmacol Ther 2009; 32:167-76. [PMID: 19290947 DOI: 10.1111/j.1365-2885.2008.01017.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
P-glycoprotein (P-gp) is an important drug transporter, which is expressed in a variety of cells, such as the intestinal enterocytes, the hepatocytes, the renal tubular cells and the intestinal and peripheral blood lymphocytes. We have studied the localization and the gene and protein expression of P-gp in these cells in horse. In addition we have compared the protein sequence of P-gp in horse with the protein sequences of P-gp in several other species. Real time RT-PCR and Western blot showed gene and protein expression of horse P-gp in all parts of the intestines, but there was no strict correlation between these parameters. Immunohistochemistry showed localization of P-gp in the apical cell membranes of the enterocytes and, in addition, staining was observed in the intestinal intraepithelial and lamina propria lymphocytes. Peripheral blood lymphocytes also stained for P-gp, and gene and protein expression of P-gp were observed in these cells. There was a high gene and protein expression of P-gp in the liver, with P-gp-immunoreactivity in the bile canalicular membranes of the hepatocytes. Gene and protein expression of P-gp were found in the kidney with localization of the protein in different parts of the nephrons. Protein sequence alignment showed that horse P-gp has two amino acid insertions at the N-terminal region of the protein, which are not present in several other species examined. One of these is a 99 amino acid long sequence inserted at amino acid positions 23-121 from the N-terminal. The other is a six amino acid long sequence present at the amino acid positions 140-145 from the N-terminal. The results of the present study indicate that P-gp has an important function for oral bioavailability, distribution and excretion of substrate compounds in horse.
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Affiliation(s)
- E Tydén
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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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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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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Olsén L, Ingvast-Larsson C, Larsson P, Broström H, Bondesson U, Sundqvist M, Tjälve H. Fexofenadine in horses: pharmacokinetics, pharmacodynamics and effect of ivermectin pretreatment. J Vet Pharmacol Ther 2006; 29:129-35. [PMID: 16515667 DOI: 10.1111/j.1365-2885.2006.00724.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pharmacokinetics and the effects on inhibition of histamine-induced cutaneous wheal formation of the histamine H1-antagonist fexofenadine were studied in horse. The effect of ivermectin pretreatment on the pharmacokinetics of fexofenadine was also examined. After intravenous infusion of fexofenadine at 0.7 mg/kg bw the mean terminal half-life was 2.4 h (range: 2.0-2.7 h), the apparent volume of distribution 0.8 L/kg (0.5-0.9 L/kg), and the total body clearance 0.8 L/h/kg (0.6-1.2 L/h/kg). After oral administration of fexofenadine at 10 mg/kg bw bioavailability was 2.6% (1.9-2.9%). Ivermectin pretreatment (0.2 mg/kg, p.o.) 12 h before oral fexofenadine decreased the bioavailability to 1.5% (1.4-2.1%). In addition, the area under the plasma concentration-time curve decreased 27%. Ivermectin did not affect the pharmacokinetics of i.v. administered fexofenadine. Ivermectin may influence fexofenadine absorption by interfering in intestinal efflux and influx pumps, such as P-glycoprotein and the organic anion transport polypeptide family. Oral and i.v. fexofenadine significantly decreased histamine-induced wheal formation, with a maximal duration of 6 h. A pharmacokinetic/pharmacodynamic link model indicated that fexofenadine in horse has antihistaminic effects at low plasma concentrations (EC50 = 16 ng/mL). However, oral treatments of horses with fexofenadine may not be suitable due to the low bioavailability.
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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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Tevell A, Bondesson U, Törneke K, Hedeland M. Identification of some new clemastine metabolites in dog, horse, and human urine with liquid chromatography/tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2004; 18:2267-2272. [PMID: 15384147 DOI: 10.1002/rcm.1622] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The metabolism of clemastine was studied in dogs, horses, and humans after a single dose of Tavegyl. The urine collected was extracted by solid-phase extraction or hydrolyzed with beta-glucuronidase and then extracted by liquid-liquid extraction, prior to analysis for unchanged drug and phase I and II metabolites by liquid chromatography/tandem mass spectrometry. The metabolites were identified by their molecular mass and interpretation of the product ion spectra, since no standard substances were available. Unchanged drug was recovered in urine samples from dogs and humans, but not from horses. In dogs and humans, the phase I metabolite, norclemastine, was identified, and clemastine metabolites with one and two additional oxygens were found in all three species. In horses and dogs monohydroxylation on one of the aromatic rings or the adjacent methyl group was favored while, in humans, the additional oxygen was positioned on either the aromatic or the aliphatic part of the structure, and the aliphatic reaction seemed to result in at least three isomers. In the metabolites with two additional oxygens, both the oxygens were found on the aliphatic fragment in humans and dogs, whereas they were situated on the aromatic part of the structure in horses. In human patients, glucuronidated monohydroxyclemastine was recovered, and in urine from horses both mono- and dihydroxyclemastine glucuronides were identified, while phase II metabolites could not be recovered from the dog urine. Clemastine metabolism in dogs and horses has, to our knowledge, not been studied before, and new metabolites from humans are presented in this article. Thus, the metabolites described in the present work have not been previously reported in the literature.
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Affiliation(s)
- Annica Tevell
- Division of Analytical Pharmaceutical Chemistry, Uppsala University, BMC, SE-751 23 Uppsala, Sweden
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