Review Current concepts on the use of antimicrobials in cats G.A. Albarellos a, * , M.F. Landoni b a Ca ´ tedra de Farmacologı ´a, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Chorroarı ´n 280 (1427), Buenos Aires, Argentina b Ca ´ tedra de Farmacologı ´a, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Buenos Aires, Argentina Accepted 4 January 2008 Abstract This article reviews the general pharmacological properties of antimicrobial drugs used in feline medicine. It focuses on recent advances in pharmacokinetics, providing an update on indications, drug interactions and adverse reactions or toxicity in the cat. Atten- tion is given to the most used groups, such as cephalosporins and fluoroquinolones, reviewing their basic features and clinical uses, and discusses the pharmacokinetic advantages of the newer members of each group. The older groups (penicillins, aminoglycosides, macro- lides and tetracyclines) are also considered with regard to their general features and current uses, and any recent reports on adverse reac- tions in cats are provided. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Antibiotics; Antimicrobials; Chemotherapy; Pharmacokinetics; Cats; Feline Introduction The cat is a popular pet worldwide but pharmacological and clinical studies in cats have not been undertaken as frequently as in dogs and, as a result, clinicians must often extrapolate data from dog or human reports. However, species do differ both in terms of dose (mg/kg) and dosing rate (dose/dosage interval) required to produce the required pharmacological effects, reflecting variations in pharmacokinetic behaviour or pharmacodynamic activity, or both. Pharmacokinetic differences between species may be due to physiological or pathophysiological idiosyncrasy (for examples in cats, see Boothe, 1990a,b,c). There certainly seems to be minor diversity in the absorption process between cats and other carnivorous species, such as dogs. Moreover, in the distribution process, there are disparities due to drug protein binding or body water distribution. The blood volume of cats (70 mL/kg) is smaller than in dogs (90 mL/kg) (Boothe, 1990a) and it is important to recognise that cats do not maintain hydration as efficiently as dogs. Probably the major pharmacological difference between cats and dogs is related to drug metabolism (Wilke, 1984). Although deficiencies in phase I reactions (methylation and hydroxylation) have been reported, there is no doubt that the deficiency of cats in phase II (glucuronoconjugation) is the most important clinically. Defective synthesis of glu- curonides in cats is related to low levels of the transferring enzyme glucuronyl transferase. This relative deficiency in the glucuronoconjugation pathway results in more drug being conjugated to sulfates. However, sulfate conjugation has a finite capacity, which is lower in cats than in other species (Aronson and Drobatz, 1996). Glucuronyl transfer- ase deficiency decreases clearance such that a longer elimi- nation half-life is observed for phenols, aromatic acids and amides. Most bacterial pathogens and infection locations are similar in cats to those in dogs, but there are exceptions such as Mycoplasma spp., Chlamydophila spp., Pasteurella spp., Nocardia spp., Toxoplasma spp., Mycobacterium spp. and Bartonella spp. The aim of this review is to provide an update on the advances in antimicrobial agents used in cats 1090-0233/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2008.01.001 * Corresponding author. Tel.: +54 11 45248459. E-mail address: albarell@fvet.uba.ar (G.A. Albarellos). www.elsevier.com/locate/tvjl Available online at www.sciencedirect.com The Veterinary Journal 180 (2009) 304–316 The Veterinary Journal