Adverse effects experienced by patients taking timolol.

Adverse effects involving one or more organ systems occurred in 38 of 165 patients with various types of glaucoma when timolol was added to their glaucoma therapy. It was necessary to discontinue timolol because of these side effects in 15 (9%) of the patients. Double-masked studies will be necessary to clarify the relationship of these adverse effects to the use of timolol.