The pharmacokinetics of single-dose oral atorvastatin and its metabolites support therapeutic use in cockatiels (Nymphicus hollandicus).

OBJECTIVE: To evaluate the plasma concentrations and determine the pharmacokinetic parameters of atorvastatin and its primary active metabolites (para- and orthohydroxyatorvastatin) after administration of a single oral dose in cockatiels (Nymphicus hollandicus).

ANIMALS: 14 adult cockatiels (7 male, 7 female) around 2 years of age.

METHODS: A compounded oral suspension of atorvastatin 10 mg/mL made with an oral suspending agent and an oral sweetener was administered via oral gavage at 20 mg/kg to each bird. Blood samples were collected at 7 different time points from 0.5 to 24 hours postadministration in a balanced incomplete block design with 3 blood samples per bird and 6 replicates per time point. Plasma concentrations of atorvastatin, parahydroxyatorvastatin, and orthohydroxyatorvastatin were determined by liquid chromatography-tandem mass spectrometry. Pharmacokinetic analysis was performed using noncompartmental analysis.

RESULTS: The estimated time to maximum concentration (tmax) for atorvastatin, parahydroxyatorvastatin, and orthohydroxyatorvastatin was 3 hours for each. The estimated maximum plasma concentration (Cmax) for atorvastatin, parahydroxyatorvastatin, and orthohydroxyatorvastatin was 152.6, 172.4, and 68.8 ng/mL, respectively. The terminal half-lives were 4, 6.8, and 4.6 hours, respectively.

CLINICAL RELEVANCE: These results support the therapeutic use of atorvastatin at the dose evaluated in this species based on human pharmacokinetic data. A starting dose of 20 mg/kg PO every 12 to 24 hours could be used to treat lipid disorders in cockatiels pending more data on multidose use and hypolipidemic efficacy.