Pharmacotherapy in congestive heart failure: Cardiopulmonary effects of ophthalmically administered beta-blockers.
Early clinical studies reported that timolol and other topical beta-blockers were effective in reducing intraocular pressure, without the side effects associated with other antiglaucoma agents. However, because people with cardiovascular or respiratory diseases were generally excluded from many of these early studies, the risk of serious cardiovascular and respiratory side effects was seriously underestimated. Once these drugs were made available to the general population, reports of systemic side effects began to proliferate. Very quickly adverse effects from topical beta-blockade became "old news." Despite this new found recognition, many treating physicians still remained unaware of the potential for systemic beta-blockade from topical applied beta-blockers. A significant portion of a topically administered dose of a beta-blocker can be absorbed and thereby effect systemic beta-blockade. Sensitivity to systemic beta-blockade can be quite dramatic in certain highly susceptible patients, particularly those with either cardiac or pulmonary abnormalities. Careful review of patients' medications will generally lessen, but not completely eliminate, the risk of undesired complications attributable to topical beta-blockade.
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Division of Clinical Pharmacology and Hypertension, Medical College of Virginia of Virginia Commonwealth University, Richmond, VA 23298-0160.