As with other topically applied ophthalmic drugs, Timoptol may be absorbed systemically.
The same adverse reactions found with systemic administration of β-adrenergic blocking agents may occur with topical administration.
Cardio-respiratory reactions: Cardiac failure should be adequately controlled before beginning therapy with Timoptol. Patients with a history of cardiovascular disease including cardiac failure, should be watched for signs of deterioration of these diseases, and pulse rates should be checked.
Due to its negative effect on conduction time, β-blockers should be given with caution to patients with first degree heart block.
Respiratory and cardiac reactions, including death due to bronchospasm in patients with asthma and rarely death in association with cardiac failure, have been reported following administration of Timoptol.
In patients with mild/moderate chronic obstructive pulmonary disease (COPD), Timoptol should be used with caution, and only if the potential benefit outweighs the potential risk.
Vascular Disorders: Patients with severe peripheral circulatory disturbance/disorders (eg, severe form of Raynaud's disease or Raynaud's syndrome) should be treated with caution.
Masking of Hypoglycemic Symptoms in Patients with Diabetes Mellitus: Beta-adrenergic blocking agents should be administered with caution in patients subject to spontaneous hypoglycemia or to diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents. Beta-adrenergic blocking agents may mask the signs and symptoms of acute hypoglycemia.
Masking of Thyrotoxicosis: Beta-adrenergic blocking agents may mask certain clinical signs of hyperthyroidism (eg, tachycardia). Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of β-adrenergic blocking agents which might precipitate a thyroid storm.
Surgical Anesthesia: The necessity or desirability of withdrawal of β-adrenergic blocking agents prior to major surgery is controversial. If necessary during surgery, the effects of β-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists.
Others: Patients who are already receiving a β-adrenergic blocking agent systemically and who are given TIMOLOL MALEATE (TIMOPTOL) should be observed for a potential additive effect either on the intraocular pressure or on the known systemic effects of β-blockade. The use of 2 topical β-adrenergic blocking agents is not recommended.
In patients with angle-closure glaucoma, the immediate objective of treatment is to reopen the angle. This requires constricting the pupil with a miotic. TIMOLOL MALEATE (TIMOPTOL) has little or no effect on the pupil. When TIMOLOL MALEATE (TIMOPTOL) is used to reduce elevated intraocular pressure in angle-closure glaucoma, it should be used with a miotic and not alone.
Choroidal detachment has been reported with administration of aqueous suppressant therapy (eg, timolol, acetazolamide) after filtration procedures.
TIMOLOL MALEATE (TIMOLOL) contains the preservative benzalkonium chloride, which may be absorbed in soft contact lenses; therefore, TIMOLOL MALEATE (TIMOPTOL) should not be used while wearing these lenses. The lenses should be removed before application of the drops and not be reinserted earlier than 15 minutes after use.
Risk from Anaphylactic Reaction: While taking β-blockers, patients with a history of atopy or a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge with such allergens, either accidental, diagnostic or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat anaphylactic reactions.