Effect of brinzolamide and dorzolamide on aqueous humor flow in human eyes.
OBJECTIVE
To measure the relative efficacy of brinzolamide hydrochloride 1% ophthalmic suspension, a new carbonic anhydrase inhibitor, compared with the currently used dorzolamide hydrochloride 2% ophthalmic solution as suppressors of aqueous humor flow in human eyes, and to study the difference of effect during the day and at night.


METHODS
A randomized, double-masked, placebo-controlled study of 25 normal human subjects was carried out at Mayo Clinic. The daytime rate of aqueous humor flow was measured every 2 hours from 8 AM to 4 PM by means of fluorophotometry. Likewise, the night-time rate of aqueous humor flow was measured every 2 hours from 12 AM to 6 AM. Intraocular pressure was measured at 4 PM and 6 AM.


RESULTS
Brinzolamide reduced aqueous flow by 0.47+/-0.20 microl per min (mean+/-SD) during the day, whereas dorzolamide reduced flow by 0.34+/-0.20 microl per min. Brinzolamide reduced aqueous flow by 0.16+/-0.12 microl per min during the night, whereas dorzolamide reduced flow by 0.10+/-0.13 microl per min. Brinzolamide reduced afternoon intraocular pressure by 1.5+/-1.1 mm Hg, and dorzolamide reduced afternoon intraocular pressure by 1.1+/-1.0 mm Hg. Brinzolamide reduced the morning awakening intraocular pressure by 0.3+/-1.6 mm Hg, and dorzolamide reduced it by 0.8+/-1.0 mm Hg.


CONCLUSIONS
Our data support the idea that brinzolamide is at least as efficacious as dorzolamide as a suppressor of aqueous humor flow in normal human eyes and that there is probably not a clinically significant difference between the two drugs in this efficacy. Clinicians who prescribe brinzolamide should expect similar ocular hypotensive responses from brinzolamide and dorzolamide.
Ingram
C J
CJ
Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Brubaker
R F
RF
D000328:Adult; D001082:Aqueous Humor / Q000187:drug effects* / Q000378:metabolism*; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D004341:Drug Evaluation; D005260:Female; D019793:Fluorescein / Q000378:metabolism; D015590:Fluorophotometry; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000494:pharmacology; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D013843:Thiazines / Q000008:administration & dosage / Q000494:pharmacology*; D013876:Thiophenes / Q000008:administration & dosage / Q000494:pharmacology*
D002257:Carbonic Anhydrase Inhibitors; D009883:Ophthalmic Solutions; D013449:Sulfonamides; D013843:Thiazines; D013876:Thiophenes; C111827:brinzolamide; C062765:dorzolamide; D019793:Fluorescein