Pharmacokinetics and selected pharmacodynamics of trazodone following intravenous and oral administration to horses undergoing fitness training
| Autor: | Khursheed R. Mama, Philip H. Kass, Eugene Steffey, Heather K Knych, Scott D Stanley |
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| Rok vydání: | 2017 |
| Předmět: |
Male
040301 veterinary sciences Sedation Administration Oral Biological Availability Pharmacology 030226 pharmacology & pharmacy 0403 veterinary science 03 medical and health sciences 0302 clinical medicine Pharmacokinetics Oral administration Physical Conditioning Animal medicine Animals Horses Volume of distribution Cross-Over Studies General Veterinary business.industry Trazodone Horse 04 agricultural and veterinary sciences General Medicine Crossover study Pharmacodynamics Anesthesia Administration Intravenous Female medicine.symptom business Half-Life medicine.drug |
| Zdroj: | American Journal of Veterinary Research. 78:1182-1192 |
| ISSN: | 0002-9645 |
| Popis: | OBJECTIVE To measure concentrations of trazodone and its major metabolite in plasma and urine after administration to healthy horses and concurrently assess selected physiologic and behavioral effects of the drug. ANIMALS 11 Thoroughbred horses enrolled in a fitness training program. PROCEDURES In a pilot investigation, 4 horses received trazodone IV (n = 2) or orally (2) to select a dose for the full study; 1 horse received a vehicle control treatment IV. For the full study, trazodone was initially administered IV (1.5 mg/kg) to 6 horses and subsequently given orally (4 mg/kg), with a 5-week washout period between treatments. Blood and urine samples were collected prior to drug administration and at multiple time points up to 48 hours afterward. Samples were analyzed for trazodone and metabolite concentrations, and pharmacokinetic parameters were determined; plasma drug concentrations following IV administration best fit a 3-compartment model. Behavioral and physiologic effects were assessed. RESULTS After IV administration, total clearance of trazodone was 6.85 ± 2.80 mL/min/kg, volume of distribution at steady state was 1.06 ± 0.07 L/kg, and elimination half-life was 8.58 ± 1.88 hours. Terminal phase half-life was 7.11 ± 1.70 hours after oral administration. Horses had signs of aggression and excitation, tremors, and ataxia at the highest IV dose (2 mg/kg) in the pilot investigation. After IV drug administration in the full study (1.5 mg/kg), horses were ataxic and had tremors; sedation was evident after oral administration. CONCLUSIONS AND CLINICAL RELEVANCE Administration of trazodone to horses elicited a wide range of effects. Additional study is warranted before clinical use of trazodone in horses can be recommended. |
| Databáze: | OpenAIRE |
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