Compositions comprising at least one bactericidal antibiotic from the group of macrolides and a non-steroid anti-inflammatory with selective inhibiting activity for cycloxygenase 2 (COX-2). The present invention also refers to a dosage form of said compositions, as well as a method to treat pet animals, particularly dogs and cats. Compositions of the present invention are particularly useful for administration to provide animals with dosages of about 1.0 to 50 mg of compound A/kg of body weight of the animal and about 0.05 to 5.0 mg of compound B/kg of body weight of the animal, being compound A preferably azithromycin and compound B, meloxicam.
