Effect of varying drop size on the efficacy and safety of a topical beta blocker.

We studied the effects on efficacy and safety of varying the drop size of a topical solution of levobunolol 0.5%. In a double-masked, crossover acute study, we administered a single drop of either 35 microL of vehicle, or 20, 35, or 50 microL of levobunolol one hour before the subjects began a ten-minute treadmill challenge electrocardiogram. After exercise the mean heart rate was 111 beats per minute (bpm) in the vehicle group and 102 to 103 bpm in the three levobunolol groups, which were significantly different from the control group but not from each other. In a randomized double-masked, parallel, chronic study, 117 patients with elevated intraocular pressure (IOP) instilled one of the three drop sizes of levobunolol twice daily for three months. Mean decreases in IOP ranged from 5.1 to 6.0 mmHg in the three groups, not significantly different from each other in mean IOP, heart rate, or blood pressure. We conclude that drop size in the range tested had no clinically significant effect on either efficacy or safety of a beta blocker such as levobunolol.

Ideal concentration of tropicamide with hydroxyamphetamine 1% for routine pupillary dilation.

In this double-masked clinical study, we evaluated four concentrations of tropicamide (0.05%, 0.1%, 0.25%, and 0.5%) combined with hydroxyamphetamine 1% to find the combination that gives maximal pupillary dilation and inhibition of responsiveness to light and minimal paralysis of accommodation. With all concentrations, pupil size was maximal at 60 minutes, and there was no significant difference between the groups in mean pupillary diameter. Inhibition of the pupillary responses to light and loss of accommodation were directly related to the concentration of tropicamide. Tropicamide 0.25% combined with hydroxyamphetamine 1% was considered ideal for dilation and inhibition of the light response without inhibiting accommodation for near vision.

Levobunolol and betaxolol. A double-masked controlled comparison of efficacy and safety in patients with elevated intraocular pressure.

In a double-masked, randomized, controlled clinical trial, the authors evaluated the ocular hypotensive efficacy of twice-daily treatment with levobunolol (0.25 and 0.5%) and betaxolol (0.5%) in 85 patients with open-angle glaucoma or ocular hypertension. During the 3-month study, intraocular pressure (IOP) reductions in the two levobunolol groups were significantly greater than in the betaxolol group. From a mean baseline IOP of approximately 25 mmHg, overall mean reductions were 6.2 and 6.0 mmHg for the 0.25 and 0.5% levobunolol groups, respectively, and 3.7 mmHg for the betaxolol group. No clinically or statistically significant among-group differences were noted in the systemic safety variables evaluated. These data suggest that although all three treatments are effective, levobunolol provides a greater reduction in IOP than betaxolol.

Glaucoma treatment with once-daily levobunolol.

Although twice-daily instillation of topical beta-blockers is the standard regimen for treatment of increased intraocular pressure, once-daily therapy might improve patient compliance and provide greater safety. In a three-month, double-masked clinical trial, 92 patients with open-angle glaucoma or ocular hypertension received levobunolol 0.5% or 1% or timolol 0.5% once daily, in both eyes. Overall mean decreases in intraocular pressure were significantly greater in the groups treated with levobunolol than in the group treated with timolol. Intraocular pressure decreases averaged 7.0 mm Hg with levobunolol 0.5%, 6.5 mm Hg with levobunolol 1%, and 4.5 mm Hg with timolol. The intraocular pressures of 72% (18 of 25 patients) of those treated with levobunolol 0.5%, 79% (22 of 28 patients) of those treated with levobunolol 1%, and 64% (16 of 25 patients) of those treated with timolol were successfully controlled during the study. Heart rate and blood pressure decreases were minimal with both levobunolol and timolol. Study results indicated that once-daily treatment with levobunolol and, to a lesser extent, timolol is sufficient to control intraocular pressure successfully and safely.

Efficacy of cimetidine/pyrilamine eyedrops. A dose response study with histamine challenge.

Eighteen healthy volunteers participated in a histamine challenge, dose response study of cimetidine (H2 antagonist)/pyrilamine (H1 antagonist) eyedrops. This was a randomized, double-masked, multiple-crossover trial, consisting of six visits spaced 48 hours apart. At each visit, subjects were pretreated with one of six different doses of test medication in one randomly selected eye and with vehicle in the fellow eye. Five minutes later, one drop of 0.0075% histamine was instilled in both eyes. Conjunctival hyperemia and edema were graded at various time points during a 20-minute interval after the instillation of histamine. Results indicated that the cimetidine/pyrilamine combination was effective in preventing histamine-induced conjunctival hyperemia in normal volunteers; neither cimetidine nor pyrilamine was effective when administered alone.