As with other topically applied ophthalmic drugs, this drug may be absorbed systemically.
The same adverse reactions found with systemic administration of beta-adrenergic blocking agents may occur with topical administration.
Cardiac disease should be adequately controlled before beginning therapy with timolol maleate. In patients with history of severe cardiac problems, signs of cardiac failure should be sought and pulse rates should be monitored.
Potential complications of therapy with timolol maleate include: Respiratory complications, including death due to bronchospasm in patients with asthma, and cardiac complications, including cardiac failure, have been reported following administration of beta-adrenergic blocking agents. However, reports of deaths have been rare.
Patients already receiving a beta-adrenergic blocking agent systemically and who are given timolol maleate should be observed for a potential additive effect either on the intraocular pressure or on the known systemic effects of beta blockade. Concomitant use of two topical beta-adrenergic blocking agents is not recommended.
For angle-closure glaucoma patients, the immediate objective of treatment is to reopen the angle. Constricting the pupil with a miotic is necessary. Timolol maleate has little or no effect on the pupil. In angle-closure glaucoma, Timolol maleate should be used with a miotic.
There have been reports of Choroidal detachment with administration of aqueous suppressant therapy (e.g. timolol, acetazolamide) after filtration procedures.
Timolol maleate has not been studied in patients wearing contact lenses.