Timolol in the treatment of open angle glaucoma.

Timolol maleate is the first beta-adrenergic-blocking drug available in the United States for topical therapy in open angle glaucoma. It may be used alone for initial therapy in selected patients or with other antiglaucoma drugs in patients requiring additional control. It should be tried, before resorting to surgery, when traditional maximal medical therapy has failed or is not tolerated. Timolol has few local side effects, but since it is absorbed, it may produce systemic reactions similar to those induced by orally administered propranolol hydrochloride. Timolol appears to be an important advance in antiglaucoma therapy, although further experience is needed to determine whether its long-term usefulness will be limited by the development of tolerance or the appearance of unexpected side effects.