Comparative acute effects of brimonidine 0.2% versus dorzolamide 2% combined with beta-blockers in glaucoma.
OBJECTIVE
To assess the acute intraocular hypotensive efficacy of brimonidine tartrate 0.2% (a highly selective alpha2-adrenergic agonist) compared with dorzolamide 2% (a topical carbonic anhydrase inhibitor) as adjunct therapy to topical beta-blockers in patients with primary open-angle glaucoma.


METHODS
A randomized cross-over masked study was performed. We enrolled one eye of each of 28 patients who were on different beta-blocker therapy. We measured the intraocular pressure (IOP) 2 h after the beta-blocker instillation; we then randomly administered one of the two drugs and we compiled an IOP diurnal curve. One month later we repeated the same procedures with the second drug. Unpaired Mann-Whitney U-test was used to compare decreases in IOP between the two drugs (P<0.05).


RESULTS
Both brimonidine 0.2% and dorzolamide 2% have good ocular hypotensive efficacy, significantly lowering IOP when compared to beta-blocker therapy alone, for the whole diurnal curve. Maximum mean percent IOP decrease from baseline was 22.0+/-15.7% (4.0+/-2.9 mmHg) for dorzolamide 2% 6 h after instillation and 35.5+/-16.4% (7.0+/-4.1 mmHg) for brimonidine 0.2% 8 h after administration of the drug. When we compared the two treatments, brimonidine 0.2% showed a higher hypotensive effect than 2% dorzolamide after 4 h (28.4+/-16.8% vs 17.6 +/-9.3%; P=0.04) and 8 h (35.5+/-16.4% vs 21.6 +/-10.8%; P=0.04).


CONCLUSIONS
This study indicates that 0.2% brimonidine acutely associated with beta-blockers is an interesting new combination treatment useful in the management of glaucoma.
Centofanti
M
M
Department of Ophthalmology, University of Rome Tor Vergata, Italy. mcentofanti@lycosmail.com
Manni
G
G
Gregori
D
D
Cocco
F
F
Lorenzano
D
D
Bucci
M G
MG
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D000068438:Brimonidine Tartrate; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000627:therapeutic use; D011810:Quinoxalines / Q000008:administration & dosage / Q000627:therapeutic use*; D013449:Sulfonamides / Q000008:administration & dosage / Q000627:therapeutic use*; D013876:Thiophenes / Q000008:administration & dosage / Q000627:therapeutic use*; D014065:Tonometry, Ocular; D016896:Treatment Outcome
D000316:Adrenergic alpha-Agonists; D000319:Adrenergic beta-Antagonists; D002257:Carbonic Anhydrase Inhibitors; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D013449:Sulfonamides; D013876:Thiophenes; D000068438:Brimonidine Tartrate; C062765:dorzolamide