Corticosteroids can exacerbate
bacterial ocular infections, even in the presence of
antibiotics.
Ketorolac tromethamine is a new non-steroidal compound being considered as an anti-inflammatory ophthalmic
drug. In this study, rabbits ocularly infected with Pseudomonas aeruginosa were treated topically with 0.4 percent
tobramycin sulfate 4 times daily for 7 days to control infection. At the same times, either 0.5 percent
ketorolac, 0.1 percent
dexamethasone or vehicle was also given topically. Animals were scored for severity of both
conjunctivitis (maximum severity rates score of 10) and
corneal opacity (maximum of 4) using the Draize scale. Severity of the
infection was determined by counting the number of punctate lesions which developed on the cornea. Nine days
after treatment ended, the number of these lesions was the same for
ketorolac as for the vehicle (respectively, 16.7 +/- 3 and 13.8 +/- 3, mean +/- SE, n = 24), indicating no exacerbation of the
infection, whereas with
dexamethasone these parameters increased (30.2 +/- 4, n = 24). During treatment,
ketorolac reduced
conjunctivitis (1.8 +/- 0.2, n = 120) when compared with the vehicle (2.9 +/- 0.2, n = 120), whereas
dexamethasone did not (3.8 +/- 0.2, n V 120); neither
ketorolac nor
dexamethasone reduced
corneal opacity (respectively, 2.3 +/- 0.05 and 2.6 +/- 0.1, n = 24) compared with vehicle (2.2 +/- 0.05, n = 24).
After treatment, both
conjunctivitis and
corneal opacity became more severe only in
dexamethasone treated eyes (respectively, 4.4 +/- 0.2, n = 120 and 3.0 +/- 0.02, n = 24). Thus,
ketorolac appears to be an
anti-inflammatory agent that does not worsen
bacterial ocular infection.