Meloxicam e prednisona: efeito do tratamento oral de curto prazo nos níveis de pressão intra-ocular de cães (Canis familiaris)

Abstract

It is recognized the role of prostaglandins in lowering de intraocular pressure, and more recently, the observation of constitutive expression of COX-2 in the healthy eyes and the absence of this isoenzyme in glaucomatous eyes. These discoveries bring the hypothesis that the use of anti-inflammatory drugs may cause, as unwanted effects, ocular hypertension through the inhibition of COX expression and the reduction of prostaglandins production. The increase of intraocular pressure, even in a transient way, is a risk factor for the development of the glaucoma. In order to observe a possible ocular hypertension associated with the use of anti-inflammatory drugs, 28 beagle dogs were selected from the kennel of the Laboratory of Development of Parasiticide Products, Department of Animal Parasitology, Veterinary Institute, Universidade Federal Rural do Rio de Janeiro. On day 0 (zero) the totality of animals had their intraocular pressure measured using applanation tonometry at 8 a.m. and 4 p.m., for evaluation of intraocular pressure before treatment; on the following day 10 animals received meloxican, associated with wet feeding, on dosage of 0.2 mg Kg-1 and 0.1 mg weight on the remainder of the four days, nine dogs received prednisone, associated with wet feeding, on dosage of 1,0 mg Kg-1 during five days and nine dogs received only wet feeding. On the fifth day of treatment the totality of dogs had their intraocular pressure measured again using applanation tonometry at 8 a.m. and 4 p.m. For all groups, including control-group, the highest average values of intraocular pressure were observed on day 5 (five). The difference between intra-ocular pressure mensurations of the 08 hours and of the 16 hours was significant, independent of treatment and of the considered day. The use of both steroidal or non-steroidal anti-inflammatory were not capable of causing ocular hypertension and some factors can be incriminated, such as route of administration, dosage and duration of therapy chosen, besides genetic inheritance and absence of glaucomatous disorder between the selected dogs.