Pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots ( Amazona amazonica ).

OBJECTIVE To determine the pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica). ANIMALS 12 adult orange-winged Amazon parrots (6 males and 6 females). PROCEDURES A single dose of amantadine was orally administered to 6 birds at 5 mg/kg (n = 2), 10 mg/kg (2), and 20 mg/kg (2) in a preliminary trial. On the basis of the results, a single dose of amantadine (10 mg/kg, PO) was administered to 6 other birds. Two months later, multiple doses of amantadine (5 mg/kg, PO, q 24 h for 7 days) were administered to 8 birds. Heart rate, respiratory rate, behavior, and urofeces were monitored. Plasma concentrations of amantadine were measured via tandem liquid chromatography-mass spectrometry. Pharmacokinetic parameter estimates were determined via noncompartmental analysis. RESULTS Mean +/- SD maximum plasma concentration, time to maximum plasma concentration, half-life, and area under the concentration-versus-time curve from the last dose to infinity were 1,174 +/- 186 ng/mL, 3.8 +/- 1.8 hours, 23.2 +/- 2.9 hours, and 38.6 +/- 7.4 mu g.h/mL, respectively, after a single dose and 1,185 +/- 270 ng/mL, 3.0 +/- 2.4 hours, 21.5 +/- 5.3 hours, and 26.3 +/- 5.7 mu g.h/mL, respectively, at steady state after multiple doses. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Once-daily oral administration of amantadine at 5 mg/kg to orange-winged Amazon parrots maintained plasma concentrations above those considered to be therapeutic in dogs. Further studies evaluating safety and efficacy of amantadine in orange-winged Amazon parrots are warranted.