Amoxicillin has antimicrobial activity against most gram-positive and many gram-negative bacteria and is widely used to treat skin and soft tissue infections, respiratory infections, and urinary tract infections in cats. In this study, the pharmacokinetics of a flavored amoxicillin paste were evaluated. Eight healthy conditioned laboratory cats received 11 mg/kg PO of a flavored paste (VETOMOXIN, Vetoquinol NA Inc.;www.vetoquinol.com). Blood samples were collected every 30 minutes after administration for 12 hours, and plasma amoxicillin concentrations were determined by using liquid chromatography. In this study, the mean time at which values exceeded the minimum inhibitory concentration (MIC) was 7.9 hours, assuming an MIC of 0.5 µg/ml. Amoxicillin is a time-dependent bactericidal antimicrobial, and the mean percentage of time at which the dosing interval was above the MIC in this study was 66%.

COMMENTARY: Since amoxicillin is such a commonly used antibiotic in cats, this pharmacokinetic information is good to have. Although there are many formulations available and the drug is often flavored at compounding facilities, this is some of the first pharmacokinetics information available to show consistency with the high degree of clinical success seen.

Pharmacokinetics of a novel amoxicillin paste formulation in cats. Chicoine AL, Cox WR, Weich EI, et. al. J VET PHARMACOL THERAPEUTICS 30:172-174, 2007.