Side effects of timolol.

Timolol maleate, a nonselective beta blocker, has been associated with adverse reactions when administered topically or systemically. The current literature pertaining to timolol-related side effects and reports to the National Registry of Drug Induced Ocular Side Effects are reviewed. Knowing what side effects are associated with the systemic administration of timolol is helpful in predicting systemic side effects that may be encountered when timolol is administered topically.