warnings and cautions
5 WARNINGS AND PRECAUTIONS Same adverse reactions found with systemic administration of beta-adrenergic receptor inhibitors may occur with topical ophthalmic administration ( 5.1 ). Beta-adrenergic receptor inhibitors may mask the signs and symptoms of acute hypoglycemia and should be administered with caution in diabetic patients subject to hypoglycemia ( 5.3 ). Beta-adrenergic receptor inhibitors may mask certain clinical signs (e.g. tachycardia) or hyperthyroidism ( 5.4 ). 5.1 General As with many topically applied ophthalmic drugs, this drug is absorbed systemically. The same adverse reactions found with systemic administration of beta-adrenergic receptor inhibitors may occur with topical administration. For example, severe respiratory reactions and cardiac reactions, including death due to bronchospasm in patients with asthma, and death due to cardiac failure, have been reported with topical application of beta-adrenergic receptor inhibitors. 5.2 Cardiac Failure BETOPTIC S® Suspension has been shown to have a minor effect on heart rate and blood pressure in clinical studies. Caution should be used in treating patients with a history of cardiac failure or heart block. Treatment with BETOPTIC S® should be discontinued at the first signs of cardiac failure. 5.3 Diabetes Mellitus Beta-adrenergic receptor inhibitors should be administered with caution in patients subject to hypoglycemia or to diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents. Beta-adrenergic receptor inhibitors may mask the signs and symptoms of acute hypoglycemia. 5.4 Thyrotoxicosis Beta-adrenergic receptor inhibitors may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-adrenergic receptor inhibitors, which might precipitate a thyroid storm. 5.5 Muscle Weakness Beta-adrenergic receptor inhibitors have been reported to potentiate muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia, ptosis and generalized weakness). 5.6 Surgical Anesthesia The necessity or desirability of withdrawal of beta-adrenergic receptor inhibitors prior to major surgery is controversial. Beta-adrenergic receptor inhibitors impair the ability of the heart to respond to beta-adrenergically mediated reflex stimuli. This may augment the risk of general anesthesia in surgical procedures. Some patients receiving beta-adrenergic receptor inhibitors have experienced protracted, severe hypotension during anesthesia. Difficulty in restarting and maintaining the heartbeat has also been reported. In patients undergoing elective surgery, consider gradual withdrawal of beta-adrenergic receptor inhibitors. If necessary during surgery, the effects of beta-adrenergic receptor inhibitors may be reversed by sufficient doses of adrenergic agonists. 5.7 Bronchospasm and Obstructive Pulmonary Disease Caution should be exercised in the treatment of glaucoma patients with excessive restriction of pulmonary function. There have been reports of asthmatic attacks and pulmonary distress during betaxolol treatment. Although re-challenges of some such patients with ophthalmic betaxolol has not adversely affected pulmonary function test results, the possibility of adverse pulmonary effects in patients sensitive to beta-adrenergic receptor inhibitors cannot be ruled out. 5.8 Atopy/Anaphylaxis While taking beta-adrenergic receptor inhibitors, patients with a history of atopy or a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens. Such patients may be unresponsive to the usual doses of epinephrine used to treat anaphylactic reactions. 5.9 Angle-Closure Glaucoma In patients with angle-closure glaucoma, the immediate treatment objective is to reopen the angle. This may require constricting the pupil. Betaxolol has little or no effect on the pupil and should not be used alone in the treatment of angle-closure glaucoma. 5.10 Cerebrovascular Insufficiency Because of potential effects of beta-adrenergic receptor inhibitors on blood pressure and pulse, these inhibitors should be used with caution in patients with cerebrovascular insufficiency. If signs or symptoms suggesting reduced cerebral blood flow develop following initiation of therapy with BETOPTIC S®, alternative therapy should be considered. 5.11 Bacterial Keratitis Bacterial keratitis may occur with use of multiple dose containers of topical ophthalmic products when these containers are inadvertently contaminated by patients who, in most cases, had a concurrent corneal disease or a disruption of the ocular epithelial surface. Instruct patients on appropriate instillation techniques. [see Patient Counseling Information (17) ]. 5.12 Choroidal Detachment Choroidal detachment after filtration procedures has been reported with the administration of aqueous suppressant therapy.