Abstract • A five-week clinical trial of the concurrent administration of topical timolol maleate and oral acetazolamide was conducted to determine the additivity of the ocular hypotensive effects of the two drugs. One drop of 0.5% timolol maleate, every 12 hours, produced a mean reduction in outflow pressure from baseline of 36.0%. When added to an eye pretreated with oral acetazolamide, timolol caused an additional mean decrease in outflow pressure of 27.6%. Acetazolamide, 500 mg orally every 12 hours, produced a mean reduction in outflow pressure from baseline of 48.6%. When added to an eye receiving topical timolol, oral acetazolamide caused an additional mean decrease in outflow pressure of 43.2%. Concurrent administration of oral acetazolamide and topical timolol reduced outflow pressure only slightly less than the predicted reduction assuming full additivity of the drugs. This study supported the clinical usefulness of concurrent administration of acetazolamide and timolol to lower intraocular pressure. References 1. Yablonski ME, Zimmerman TJ, Waltman SR, et al: A fluorophotometric study of the effect of topical timolol on aqueous humor dynamics . Exp Eye Res 1978;27:135-142.Crossref 2. Coakes RL, Brubaker RF: The mechanism of timolol in lowering intraocular pressure in the normal eye . Arch Ophthalmol 1978;96:2045-2048.Crossref 3. Becker B: Decrease in intraocular pressure by a carbonic anhydrase inhibitor, Diamox . Am J Ophthalmol 1954;37:13-15. 4. Scharrer A, Ober M: Timolol und Acetazolamid bei der Behandlung aus erhohten intraocularen Drukes . Albrecht Von Graefes Arch Klin Exp Ophthalmol 1979;212:129-133.Crossref 5. Berson FG, Epstein DL: Separate and combined effects of timolol maleate and acetazolamide in open-angle glaucoma . Am J Ophthalmol 1981;92:788-791. 6. Kolker AE, Hetherington J Jr: Becker-Shaffer's Diagnosis and Therapy of the Glaucomas . St Louis, CV Mosby Co, 1976, pp 314-322. 7. Epstein DL: Carbonic anhydrase inhibitors , in Chandler PA, Grant WM (eds): Glaucoma . Philadelphia, Lea & Febiger, 1979, pp 84-87.
Archives of Ophthalmology – American Medical Association
Published: Jun 1, 1982