Pharmacology: Animal: Ketorolac tromethamine prevented the development of increased intraocular pressure induced in rabbits with topically applied arachidonic acid. Ketorolac did not inhibit rabbit lens aldose reductase in vitro.
Ketorolac tromethamine ophthalmic solution did not enhance the spread of ocular infections induced in rabbits with Candida albicans, herpes simplex virus type I or Pseudomonas aeruginosa.
Clinical: Ketorolac tromethamine is a nonsteroidal anti-inflammatory drug which, when administered systemically, has demonstrated analgesic, anti-inflammatory and antipyretic activity. The mechanism of its action is thought to be due, in part, to its ability to inhibit prostaglandin biosynthesis. Ketorolac tromethamine given systemically does not cause pupil constriction.
Prostaglandins have been shown in many animal models to be mediators of certain kinds of intraocular inflammation. In studies performed in animal eyes, prostaglandins have been shown to produce disruption of the blood-aqueous humor barrier, vasodilation, increased vascular permeability, leukocytosis and increased intraocular pressure. Prostaglandins also appear to play a role in the miotic response produced during ocular surgery by constricting the iris sphincter independently of cholinergic mechanisms.
Two drops (0.1 mL) of Acular instilled into the eyes of patients 12 hrs and 1 hr prior to cataract extraction achieved measurable levels in 8 of 9 patients' eyes (mean ketorolac concentration 95 ng/mL aqueous humor, range 40-170 ng/mL). Ocular administration of ketorolac tromethamine reduces prostaglandin E2 (PGE2) levels in aqueous humor. The mean concentration of PGE2 was 80 pg/mL in the aqueous humor of eyes receiving vehicle and 28 pg/mL in the eyes receiving Acular.
One drop (0.05 mL) of Acular was instilled into 1 eye and 1 drop of vehicle into the other eye 3 times daily in 26 normal subjects. Only 5 of 26 subjects had a detectable amount of ketorolac in their plasma (range: 10.7-22.5 ng/mL) at Day 10 during topical ocular treatment. When ketorolac tromethamine 10 mg is administered systemically every 6 hrs, peak plasma levels at steady state are around 960 ng/mL.
Two controlled clinical studies showed that Acular was significantly more effective than its vehicle in relieving ocular itching caused by seasonal allergic conjunctivitis.
Two controlled clinical studies showed that patients treated for 2 weeks with Acular were less likely to have measurable signs of inflammation (cell and flare) than patients treated with its vehicle.
Results from clinical studies indicate that Acular has no significant effect upon intraocular pressure; however, changes in intraocular pressure may occur following cataract surgery.
Acular ophthalmic solution has been safely administered in conjunction with other ophthalmic medications eg, antibiotics, β-blockers, carbonic anhydrase inhibitors, cycloplegics and mydriatics.