Dose response and duration of action of dorzolamide, a topical carbonic anhydrase inhibitor
E. A. Lippa, L. E. Carlson, B. Ehinger, L. O. Eriksson, K. Finnstrom, C. Holmin, S. E. Nilsson, K. Nyman, C. Raitta, A. Ringvold and al. et
Clinical Research, Merck Sharp & Dohme Research Laboratories, West Point, Pa. 19486.
The multiple-dose, dose-response relationship and duration of action of the
novel topical carbonic anhydrase inhibitor dorzolamide (previously known as
MK-507) were investigated in a double-masked, randomized,
placebo-controlled, parallel study in 73 patients with bilateral primary
open angle glaucoma or ocular hypertension. Dorzolamide (0.7%, 1.4%, or 2%)
or placebo was administered every 12 hours for 5 days and then every 8
hours for 7 days. Intraocular pressure was investigated with multiple
12-hour diurnal curves. All concentrations of dorzolamide demonstrated
substantial lowering of intraocular pressure throughout the day when given
twice daily (9% to 21%) or three times daily (14% to 24%). Although a
dose-dependent response was observed immediately following the first dose,
there were no significant differences between concentrations or dose
response at either the twice or three times daily dosing regimen. Three
times daily administration of 2% dorzolamide demonstrated a mean percent
decrease in intraocular pressure of 18% to 22% throughout the day (mean
decrease, 4.5 to 6.1 mm Hg). Dorzolamide appears to have substantial
potential in the treatment of glaucoma and ocular hypertension.
