Abstract
Abstract: :
Purpose: To compare the additive ocular hypotensive effect of bimatoprost (B) or travoprost (T) to latanoprost (L) in monkey eyes with laser-induced unilateral glaucoma and the effect on tonographic outflow facility (C) of B, T and L in normal monkey eyes. Methods: Four monkeys with unilateral laser-induced glaucoma were used in each treatment group. Intraocular pressure (IOP) was measured hourly for 6 hours beginning at 9:30 a.m. on day 1 (untreated baseline), days 6 and 7 (single agent therapy), and days 13 and 14 (combination therapy with two drugs). Following a one day baseline measurement, 4 eyes with glaucoma were treated either with one drop of 0.005% L or 0.004% T on days 2 through 7. Both groups received both drops 5 minutes apart on days 8 though 14. A similar experiment was carried out using L and 0.03% B (ARVO 2002). A control experiment used one drop of L for one week and two drops of L 5 minutes apart for the second week. In eight different monkeys without glaucoma, C was measured before and 1 to 2 hours after unilateral application of one drop of B, T or L. Results: The maximum additive reduction in IOP was as follows: L+T (first drug + second drug): 3.0 ± 0.6 (mean ± SEM) mmHg (p<0.05); T+L: 2.0 ± 0.4 mmHg (p<0.05); L+B: 4.8 ± 1.3 mmHg (p<0.05); B+L: 4.3 ± 0.6 mmHg (p<0.05); L+L: 0.3 ± 0.5 mmHg (p>0.60). There was an additional hypotensive response by adding B to L or T to L (p<0.05) but not by adding L to L. The additional reduction of IOP adding B to L was greater (p<0.05) than adding T to L at trough and hour 2. Compared with vehicle-treated contralateral control eyes, C was increased by 33% with B (p<0.005), by 18% with T (p<0.05), and by 18% with L (p>0.10) after single dose application in normal monkey eyes. Conclusions: The intraocular pressure effects of the commercial concentrations of either B or T are additive to a maximum dose of L. Tonographic outflow facility is increased by either B or T.
Keywords: drug toxicity/drug effects • intraocular pressure • pharmacology