Carprofen inhibition of flare in the dog measured by laser flare photometry

Abstract

The purpose of this study was to determine whether oral carprofen (Rimadyl(R)) treatment in dogs could prevent or decrease the breakdown of the blood-aqueous barrier. The topical pilocarpine irritative model was used to induce breakdown and cause flare. Pilocarpine was instilled in both eyes of seven dogs at time zero and again 5 h later. At 7 h, laser flare photometry was used to measure the flare concentration in each eye using the Kowa FC-1000 laser flare cell meter. All treatments were then discontinued. Two days later, carprofen was administered to the same dogs for a total of three doses. After the last dose of carprofen, pilocarpine treatments and flare measurements were repeated. Carprofen pretreatment resulted in a 68% inhibition of flare, which was highly significant (P < 0.01). The pilocarpine group had a mean of 16.1 photon counts per millisecond (PC ms-1) +/- 2.2 SE, and the carprofen group had a mean of 7.0 PC/ms +/- 1.2 SE. These results compare favorably with previous studies measuring increased protein or fluorescein concentrations in the aqueous humor after blood-aqueous barrier breakdown in the dog. These results suggest that carprofen may be effectively used as a systemically administered ocular anti-inflammatory drug. Carprofen has the added benefit of fewer reported side effects.

Measurements of canine aqueous humor inflammatory mediators and the effect of carprofen following anterior chamber paracentesis

“…Several NSAIDs have been investigated with experimentally induced anterior uveitis 1–3,8,12,17–19,27 . Carprofen has been studied in dogs and shown to have positive results against uveitis in one study, 17 but not in others 30,31 .…”

“…Various models of uveitis via disruption of the BAB have been used in the ophthalmic research setting, including modified paracentesis, 2–9 laser capsulotomy, 11–14 topical drug application, 9,15–18 and corneal surgery 1,19 . In addition, systemic injection of lipopolysaccharide also induced uveitis in rats 20 as well as intravitreal lipopolysaccharide injections in cats 21 .…”

“…Benefits have been seen with the topical application of flurbiprofen, 8,12,18 diclofenac and suprofen; 8,18 intravenous injection of flunixin meglumine, 3,11,12,19 lysine‐acetylsalicylate and phenylbutazone; 27 subcutaneous injection of tolfenamic acid; 1 and oral administration of aspirin 2 . Carprofen, a somewhat selective anti‐COX‐2 NSAID in the dog, has been investigated in canine models of uveitis 17,30 . In one model, carprofen was shown to be an effective treatment against canine uveitis; 17 however, this molecule has also demonstrated no beneficial effect in another canine uveitis model 30 .…”

“…Carprofen, a somewhat selective anti‐COX‐2 NSAID in the dog, has been investigated in canine models of uveitis 17,30 . In one model, carprofen was shown to be an effective treatment against canine uveitis; 17 however, this molecule has also demonstrated no beneficial effect in another canine uveitis model 30 . In a third study, the pharmacokinetic and pharmacodynamic properties of carprofen were also investigated in canine eyes with and without uveitis and showed no differences in their chosen markers of inflammation between carprofen treated and control eyes 31…”

Effect of oral administration of carprofen on intraocular pressure in normal dogs

“…Carprofen, a cyclooxygenase‐2 selective NSAID, has been evaluated in several models of uveitis in dogs, with varied results. In a pilocarpine‐induced model of experimental uveitis, pretreatment with carprofen resulted in a 68% inhibition of flare as measured by laser flare photometry (Krohne et al ., ). In a study comparing the effects of several orally administered NSAIDS on an anterior chamber paracentesis‐induced model of experimental uveitis, carprofen did not cause a significant reduction in prostaglandin production when compared to the control (Gilmour & Lehenbauer, ).…”