Correlation of serum phenytoin (diphenylhydantoin) with the administration of oral and intravenous phenytoin in dogs

Autor: David F. Kowalczyk
Rok vydání: 1980
Předmět:
Zdroj: Journal of Veterinary Pharmacology and Therapeutics. 3:237-244
ISSN: 1365-2885
0140-7783
DOI: 10.1111/j.1365-2885.1980.tb00488.x
Popis: The concentration of serum phenytoin was determined in normal dogs following the administration of phenytoin by either the intravenous or oral route. An intravenous dose of 11 and 33 mg/kg of body weight was given to six dogs and a further dose of 44 mg/kg was given to two dogs. Serial blood samples were taken following the three doses for determination of pharmacokinetic parameters. The mean half-life was 3.35, 3.84 and 4.57 h as the dose was increased. Signs of toxicity occurred immediately following the infusion of phenytoin (emesis, ataxia and seizures). In the first oral studies, serial blood samples were taken for 2 consecutive days following a dose of 11 and 88 mg/kg, t.i.d. The time—concentration profiles of phenytoin varied significantly from one day to the next in the same dog. In the second oral study, blood samples were taken at 3 and 7 h following a dose of 11, 22, 44, 66 and 88 mg/kg, t.i.d. There was a poor correlation between the size of the oral dose and the concentration of serum phenytoin. Due to the short half-life and poor absorption of phenytoin in dogs, it was concluded that the oral administration of phenytoin in dogs produces sub-therapeutic and erratic serum concentrations of phenytoin which makes its efficacy as an anti-convulsant questionable.
Databáze: OpenAIRE
Externí odkaz: