.008% timolol ophthalmic solution. A minimal-effect dose in a normal volunteer model.
A double-masked, randomized, placebo-controlled, rising-dose, single-dose study was undertaken to assess the effect of low concentrations of timolol maleate ophthalmic solution (0.008%, 0.025%, 0.08%, and 0.25%) on intraocular pressure and its diurnal variation in healthy, normal volunteers. A single dose of 0.008% timolol exhibits a definite but minimal-effect on intraocular pressure in this normal volunteer model, causing a significant peak mean decrease in intraocular pressure from its value immediately predose. This decrease was 1.8 mm Hg (a peak mean percent decrease of 12.8%) at 2 hours postdose compared with an increase of 0.1 mm Hg (+2.5%) during a pre-study curve due to normal diurnal variation. One drop of 0.008% solution represents a single dose of approximately 2.5 micrograms of timolol. A slight contralateral ocular hypotensive effect appears to be present for 0.25% timolol at 2 hours postdose although it just failed to reach statistical significance.
Department of Ophthalmology, Jefferson Medical College, Philadelphia, Pa.
L S
LS
Mottow-Lippa
E A
EA
Lippa
M A
MA
Naidoff
R
R
Clementi
T
T
Bjornsson
K
K
Jones
D000328:Adult; D002940:Circadian Rhythm; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D016032:Randomized Controlled Trials as Topic; D013999:Timolol / Q000494:pharmacology*
D009883:Ophthalmic Solutions; D013999:Timolol