Effect of brimonidine tartrate 0.15% on scotopic pupil: controlled trial.
OBJECTIVE
The aim of this study was to evaluate the duration of the effect of one single dose of brimonidine tartrate 0.15% on pupil diameter, under scotopic conditions, when applied topically in 1 eye of normal subjects.


METHODS
The eyes of 19 normal volunteers were randomized so that 1 eye had 1 drop of brimonidine tartrate 0.15% and the other received no medication. Pupil diameter was measured using an infrared pupillometer. The first measure was obtained before the instillation of brimonidine. After that, four measures, with 2-h intervals, were performed.


RESULTS
From 19 participants, 14 were women and 5 were men, with a mean age of 25.05 years (standard deviation, +/- 6.98). Before brimonidine instillation, mean pupil diameter in the control eyes was 5.11 mm, and in the brimonidine eyes it was 5.15 mm. After 8 h, the mean pupil size was 4.01 mm in the treated eyes, and 4.56 mm in the untreated eyes. There was a tendency of miotic effect to be more important on the treated eye, as compared to the control eye in all intervals, but this did not reach statistical significance (P = 0.375). When comparing both eyes, independently of the periods, the treated eye had a smaller diameter than the untreated eye (P = 0.038). The miotic effect was observed for at least 8 h after instillation.


CONCLUSIONS
Miotic response of brimonidine tartrate 0.15% lasted for at least 8 h and has a significant effect on the nontreated eye.
Gerente
Vanessa M
VM
Department of Ophthalmology, Albert Einstein Israelite Hospital, São Paulo, Brazil.
Biondi
Adriano C
AC
Barbosa
Carolina P
CP
Lottenberg
Claudio L
CL
Paranhos
Augusto
A
D000287:Administration, Topical; D058647:Adrenergic alpha-2 Receptor Agonists; D000328:Adult; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000068438:Brimonidine Tartrate; D003623:Dark Adaptation; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D008916:Miotics / Q000008:administration & dosage / Q000494:pharmacology*; D009883:Ophthalmic Solutions; D011680:Pupil / Q000187:drug effects*; D011810:Quinoxalines / Q000008:administration & dosage / Q000494:pharmacology*
D058647:Adrenergic alpha-2 Receptor Agonists; D000959:Antihypertensive Agents; D008916:Miotics; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D000068438:Brimonidine Tartrate