Comparison of ocular hypotensive actions of fixed combinations of brimonidine/timolol and dorzolamide/timolol.
OBJECTIVE
To compare brimonidine/timolol fixed combination (BrTFC; Combigan *) with dorzolamide/timolol fixed combination (DTFC; Cosopt dagger) in terms of ability to lower intraocular pressure (IOP) in primary open-angle glaucoma (POAG).


METHODS
This was a prospective, randomized, double-masked, crossover study. After 6 weeks of therapy with timolol maleate 0.5% twice daily, patients were randomized to BrTFC twice daily or DTFC twice daily for 6 weeks, before being crossed over to the other treatment arm for a further 6 weeks. At all follow-up visits, IOP was measured at 09.00 (pre-instillation) 12.00 and 16.00. The primary outcome measure was change in mean diurnal IOP from baseline at 6 weeks. The secondary outcome was percentage of patients with IOP <18 mmHg at 6 weeks. Data were analyzed from all patients who completed the study.


RESULTS
Twenty-five patients were randomized and 20 completed the study. Mean diurnal IOP (mean +/- standard deviation [SD]) was 20.28 +/- 2.03 mmHg at timolol-treated baseline. After 6 weeks, mean diurnal IOP was 16.28 +/- 2.07 mmHg following BrTFC and 17.23 +/- 2.29 mmHg following DTFC (difference: 0.95 mmHg, 95% CI 0.10-1.80, p = 0.03). Mean IOP at 09.00 was 20.95 +/- 2.31 mmHg at baseline. This was reduced to 15.85 +/- 2.56 mmHg following BrTFC and 17.55 +/- 2.67 mmHg following DTFC (difference: 1.70, 95% CI 0.80-2.60, p = 0.001). For the 12.00 and 16.00 timepoints, the mean changes from baseline in the two arms were comparable. Percentages of patients achieving a target IOP of <18 mmHg were 85% following BrTFC and 60% following DTFC (p = NS [not significant]). No treatment-related adverse events were reported with either therapy. Key limitations include the small size of the study population and the 6-week duration of treatment periods, which prevents drawing conclusions regarding long-term therapy.


CONCLUSIONS
Reductions from baseline in mean diurnal IOP and morning IOP were greater with BrTFC than with DTFC.
García-Feijoó
Julián
J
Hospital Clínico Universitario San Carlos, Universidad Complutense, Madrid, Spain.
Sáenz-Francés
Federico
F
Martínez-de-la-Casa
José María
JM
Méndez-Hernández
Carmen
C
Fernández-Vidal
Ana
A
Calvo-González
Cristina
C
García-Sánchez
Julián
J
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000959:Antihypertensive Agents / Q000008:administration & dosage; D000068438:Brimonidine Tartrate; D018592:Cross-Over Studies; D004304:Dosage Forms; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy*; D009883:Ophthalmic Solutions / Q000008:administration & dosage; D011810:Quinoxalines / Q000008:administration & dosage*; D013449:Sulfonamides / Q000008:administration & dosage*; D013876:Thiophenes / Q000008:administration & dosage*; D013999:Timolol / Q000008:administration & dosage*
D000959:Antihypertensive Agents; D004304:Dosage Forms; D004338:Drug Combinations; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D013449:Sulfonamides; D013876:Thiophenes; D000068438:Brimonidine Tartrate; D013999:Timolol; C062765:dorzolamide