Effects of 1% topical brinzolamide on intraocular pressure in healthy dogs

Background: Glaucoma is one of the most common causes of blindness in dogs, and is generally characterized by death of the retinal ganglion cells associated with a rapid loss of vision. Increased intraocular pressure (IOP) occurs in patients with primary glaucoma, due to genetic abnormalities in pectinal ligaments and the trabeculae of the iridocorneal angle, producing inadequate drainage of aqueous humor. IOP is the result of the dynamic equilibrium between the production and drainage of aqueous humor. Intraocular surgery, anterior lens luxation, systemic diseases, immune-mediated, neoplastic and infectious diseases lead to the breakdown of the blood-aqueous barrier and increase the amount of protein and cells in aqueous humor, which can block this drainage pathway. Under these conditions, becomes indispensable the pharmacological control of IOP by reducing aqueous humor production. The main objective of the present study was to evaluate the effects of topical 1% brinzolamide on intraocular pressure (IOP) in twelve healthy dogs.Materials, Methods & Results: The age range of affected dogs was 1-5 years, with a mean age of 2.5 years. Twelve dogs were included in this study. All animals were healthy based on clinical, ophthalmic and hematological examinations. Selected animals were kept in a room with 500 lux luminosity, 56.8% relative humidity, 20C temperature, exposed to [...](AU)

Effects of 1% topical brinzolamide on intraocular pressure in healthy dogs

Background: Glaucoma is one of the most common causes of blindness in dogs, and is generally characterized by death of the retinal ganglion cells associated with a rapid loss of vision. Increased intraocular pressure (IOP) occurs in patients with primary glaucoma, due to genetic abnormalities in pectinal ligaments and the trabeculae of the iridocorneal angle, producing inadequate drainage of aqueous humor. IOP is the result of the dynamic equilibrium between the production and drainage of aqueous humor. Intraocular surgery, anterior lens luxation, systemic diseases, immune-mediated, neoplastic and infectious diseases lead to the breakdown of the blood-aqueous barrier and increase the amount of protein and cells in aqueous humor, which can block this drainage pathway. Under these conditions, becomes indispensable the pharmacological control of IOP by reducing aqueous humor production. The main objective of the present study was to evaluate the effects of topical 1% brinzolamide on intraocular pressure (IOP) in twelve healthy dogs.Materials, Methods & Results: The age range of affected dogs was 1-5 years, with a mean age of 2.5 years. Twelve dogs were included in this study. All animals were healthy based on clinical, ophthalmic and hematological examinations. Selected animals were kept in a room with 500 lux luminosity, 56.8% relative humidity, 20C temperature, exposed to [...]

EFEITOS DA TAFLUPROSTA E DA BRINZOLAMIDA SOBRE A PRESSÃO INTRAOCULAR E O DIÂMETRO PUPILAR DE CÃES SAUDÁVEIS

Objetivou-se estudar os efeitos da administração tópica da tafluprosta a 0.0015% e da brinzolamida a 1% sobre a pressão intraocular (PIO) e o diâmetro pupilar (DP) em cães saudáveis. Dois experimentos com intervalo de 10 dias foram realizados. Onze cães foram tratados com 1 gota de tafluprosta às 8h30 e 20h30, ou brinzolamida às 8h30, 14h30 e 20h30 durante 4 dias e nos olhos contralaterais foram instilados uma única gota de solução salina e classificado como olho controle A PIO e o DP foram mensurados às 8h00, 11h00, 14h00, 17h00 e 20h00 durante dois dias (basal), quatro dias de tratamento e um de pós-tratamento. Ao final de quatro dias, a tafluprosta e a brinzolamida foram capazes de reduzir de forma significativa a PIO em 2 e 1,42 mmHg respectivamente ao período basal. Comparações entre os fármacos demostrou que, ao final dos quatro dias de tratamento, a tafluprosta apresentou redução de 0,62 mmHg em relação à brinzolamida (p>0,05). Ao final do período, o valor médio da PIO dos olhos tratados com brinzolamida reduziu 0,90 mmHg, em comparação aos olhos controle (p<0,05 ao terceiro e quarto dia). Relativamente à tafluprosta, a redução foi de 3,06 mmHg (p<0,001). Comparativamente ao período basal, observou-se redução de 0,34 mm no DP nos olhos tratados com brinzolamida e de 2,55 mm com tafluprosta. Todavia, ao final do período de tratamento, o valor médio do DP dos olhos tratados com brinzolamida reduziu 0,18 mm, frente aos 3,25 mm após instilações de tafluprosta, em comparação aos olhos controle. Comparações entre os fármacos, demonstraram que o tratamento com tafluprosta ensejou redução de 2,23 mm comparativamente ao DP dos olhos tratados com brinzolamida (p < 0,001). Conclui-se que três instilações diárias de brinzolamida 1% ou duas instilações de tafluprosta 0.0015% em cães saudáveis reduzem a PIO e o DP de forma significativa, sugerindo novos experimentos com a utilização dos fármacos em animais com glaucoma e hipertensão intraocular. Apesar de apresentar valores mais baixos, não se observou significância estatística entre tafluprosta e brinzolamida, relativamente a redução da PIO. A redução do DP induzida pela brinzolamida, pode não apresentar relevância clínica, não se recomendando que o fármaco seja prescrito para indução de miose.

This study aimed to evaluate the effects of topical administration of 0.0015% tafluprost and 1% brinzolamide on intraocular pressure (IOP) and pupil diameter (PD) in healthy dogs. Two experiments were carried out after a washout period of 10 days. Eleven dogs were treated with 1 drop of tafluprosta at 8:30 a.m. and 8:30 p.m., and brinzolamide at 8:30 a.m., 14:30 and 20.30 p.m. for 4 days. IOP and PD were measured at 8 and 11 a.m.; 2, 5, and 8 p.m for two days (baseline), 4 days of treatment, and 1 of post-treatment. Following 4 days, tafluprosta and brinzolamide were able to reduce IOP by 2 and 1.42 mmHg, respectively, compared to baseline. Comparisons between drugs showed a reduction of 0.62 mm Hg at the end of 4 days of treatment period (P > 0.05). At the end of this period, the average IOP of eyes treated with brinzolamide reduced only 0.90 mmHg, in comparision to the control eyes (P < 0,05 at 3rd and 4rd days); while tafluprosta reduced IOP by 3.6 mmHg (P < 0.001). Comparisons between baseline and treated eyes, showed reductions of PD by 0.34 (brinzolamide) 2.55 mm (tafluprosta). However, at the end of this period, comparisons with the control eyes showed that the average PD of the brinzolamide treated eyes decreased only 0.18 mm vs. 3.25 mm seen in tafluprost treated eyes. It can be concluded that for 4 days of treatment with 0.0015% tafluprosta and 1% brinzolamide were able to decrease significantly the IOP and the OS and can be indicated for the treatment of glaucoma and ocular hipertension. Although slighter values of IOP were observed in eyes treated with tafluprost, statistical significance were not seen when both drugs were compared. The decrease in PD induced by brinzolamide may not be clinically relevant, suggesting that the drug is not recommended to induce miosis in the dog.