Pharmacokinetics of intravenous and oral amitriptyline and its active metabolite nortriptyline in Greyhound dogs

Amitriptyline at 4 mg kg−1 administered orally produced low amitriptyline and nortriptyline plasma concentrations. This brings into question whether the currently recommended oral dose of amitriptyline (1-4 mg kg−1) is appropriate in dogs.