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Dexamethasone treatment interferes with the pharmacokinetics of ivermectin in young cattle
- Source :
- Veterinary Parasitology, Veterinary Parasitology, Elsevier, 2012, 190 (3-4), pp.482-488. ⟨10.1016/j.vetpar.2012.07.011⟩
- Publication Year :
- 2012
- Publisher :
- Elsevier BV, 2012.
-
Abstract
- International audience; An experiment was carried out to study the possible interaction between dexamethasone (DXM) treatment and the efficacy of ivermectin (IVM) treatment in young cattle. Two groups, each of seven calves, were experimentally inoculated with an equal mixture containing 15,000 third stage larvae of Cooperia oncophora and Ostertagia ostertagi each, and with no history of being resistant to any anthelmintics. However, in this study C. oncophora was unexpectedly classified as IVM-resistant according to the outcome from the faecal egg count reduction test (FECRT). Blood parameters and faecal egg counts (FEC) were monitored from 0 to 35 days post infection (d.p.i.). The calves in one group received intramuscular injections of short and long-term acting DXM at 22 and 24 d.p.i., respectively. The other group remained as a control. Three days post patency (24 d.p.i.) both groups were injected subcutaneously with IVM (Merial) at the recommended dose (0.2 mg/kg). A significant difference (p < 0.001) in FEC patterns was observed between groups. Although both groups still excreted eggs (100-200 eggs per gram faeces) 11 days post anthelmintic treatment, the control group had a significantly higher reduction between 23 and 35 d.p.i. (p = 0.025). After 35 days, four animals per group were euthanized, and worms in the gastrointestinal tract were counted. No O. ostertagi were found in the abomasums, but low to high numbers (800-6200) of C. oncophora remained in the small intestines in both groups. Overall, these findings indicated that there was an interaction between the efficacy of IVM and DXM treatment. As significantly lower plasma levels of IVM were observed in the DXM group, we conclude that the impaired efficacy of ivermectin was most likely due to the altered pharmacokinetics. (C) 2012 Elsevier B.V. All rights reserved.
- Subjects :
- VETERINARY IMPORTANCE
Veterinary medicine
[SDV]Life Sciences [q-bio]
NEW-ZEALAND
Anti-Inflammatory Agents
Cooperia
Dexamethasone
Trichostrongyloidiasis
0403 veterinary science
Feces
Ivermectin
Ostertagiasis
INFECTION
Drug Interactions
Anthelmintic
Anthelmintic resistance
Eggs per gram
Anthelmintics
2. Zero hunger
0303 health sciences
Gastrointestinal tract
Ostertagia
P-GLYCOPROTEIN
Gastrointestinal parasites
04 agricultural and veterinary sciences
General Medicine
COUNT REDUCTION TEST
3. Good health
ASSESSING ANTHELMINTIC EFFICACY
medicine.drug
HAEMONCHUS-CONTORTUS
040301 veterinary sciences
Biology
03 medical and health sciences
Animal science
Pharmacokinetics
medicine
Animals
Parasite Egg Count
030304 developmental biology
DRUG-RESISTANCE
Macrocyclic lactones
Ostertagia ostertagi
Trichostrongyloidea
General Veterinary
NEMATODES
Cattle
Parasitology
Immunosuppression
Subjects
Details
- ISSN :
- 03044017
- Volume :
- 190
- Database :
- OpenAIRE
- Journal :
- Veterinary Parasitology
- Accession number :
- edsair.doi.dedup.....472ea6a5fc3009496c918bede6baaca6
- Full Text :
- https://doi.org/10.1016/j.vetpar.2012.07.011